Name: evaluation of hepatic glucose production in a polycystic ovary syndrome mouse model
Uploaded: 2022-03-05T13:30:00
Description: Watch this Scientific Journal Video about Evaluation of Hepatic Glucose Production in a Polycystic Ovary Syndrome Mouse Model at JoVE.com

This work was supported by training grants by the Department of Obstetrics and Gynecology, Baylor College of Medicine (ALG) and R-01 research grant (Grant # DK114689) for CSB, SC and JM from National Institutes of Health.

All animal procedures were approved by the Institutional Animal Care and Use Committee (IACUC) of the Baylor College of Medicine.
1. Preparation of [6,6-2H2]glucose
<ol>
	<li>One day before the procedure, prepare the stable isotope glucose tracer in normal saline. For this experiment, [6,6-2H2]glucose was used as a tracer to measure plasma glucose appearance rate. 
	NOTE: In this experiment, glucose production during fasting a...

<ol>
	<li>March, W. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+prevalence+of+polycystic+ovary+syndrome+in+a+community+sample+assessed+under+contrasting+diagnostic+criteria.">The prevalence of polycystic ovary syndrome in a community sample assessed under contrasting diagnostic criteria.</a> Human Reproduction. 25 (2), 544-551 (2009).</li><li>Yildiz, B. O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prevalence,+phenotype+and+cardiometabolic+risk+of+polycystic+ovary+syndrome+under+different+diagnostic+criteria.">Prevalence, phenotype and cardiometabolic risk of polycystic ovary syndrome under different diagnostic criteria.</a> Human Reproduction. 27 (10), 3067-3073 (2012).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Revised+2003+consensus+on+diagnostic+criteria+and+long-term+health+risks+related+to+polycystic+ovary+syndrome.">Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome.</a> Fertility and Sterility. 81 (1), 19-25 (2004).</li><li>Goodarzi, M. O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polycystic+ovary+syndrome:+etiology,+pathogenesis+and+diagnosis.">Polycystic ovary syndrome: etiology, pathogenesis and diagnosis.</a> Nature Reviews. Endocrinology. 7 (4), 219-231 (2011).</li><li>Azziz, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Introduction:+Determinants+of+polycystic+ovary+syndrome.">Introduction: Determinants of polycystic ovary syndrome.</a> Fertility and Sterility. 106 (1), 4-5 (2016).</li><li>Baskind, N. E., Balen, A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypothalamic-pituitary,+ovarian+and+adrenal+contributions+to+polycystic+ovary+syndrome.">Hypothalamic-pituitary, ovarian and adrenal contributions to polycystic ovary syndrome.</a> Best Practice and Research. Clinical Obstetrics &amp; Gynaecology. 37, 80-97 (2016).</li><li>Burghen, G. A., Givens, J. R., Kitabchi, A. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlation+of+hyperandrogenism+with+hyperinsulinism+in+polycystic+ovarian+disease.">Correlation of hyperandrogenism with hyperinsulinism in polycystic ovarian disease.</a> The Journal of Clinical Endocrinology and Metabolism. 50 (1), 113-116 (1980).</li><li>Bremer, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polycystic+ovary+syndrome+in+the+pediatric+population.">Polycystic ovary syndrome in the pediatric population.</a> Metabolic Syndrome and Related Disorders. 8 (5), 375-394 (2010).</li><li>Dunaif, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Excessive+insulin+receptor+serine+phosphorylation+in+cultured+fibroblasts+and+in+skeletal+muscle.+A+potential+mechanism+for+insulin+resistance+in+the+polycystic+ovary+syndrome.">Excessive insulin receptor serine phosphorylation in cultured fibroblasts and in skeletal muscle. A potential mechanism for insulin resistance in the polycystic ovary syndrome.</a> The Journal of Clinical Investigation. 96 (2), 801-810 (1995).</li><li>H&#248;jlund, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impaired+insulin-stimulated+phosphorylation+of+Akt+and+AS160+in+skeletal+muscle+of+women+with+polycystic+ovary+syndrome+is+reversed+by+pioglitazone+treatment.">Impaired insulin-stimulated phosphorylation of Akt and AS160 in skeletal muscle of women with polycystic ovary syndrome is reversed by pioglitazone treatment.</a> Diabetes. 57 (2), 357-366 (2008).</li><li>Moghetti, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Divergences+in+insulin+resistance+between+the+different+phenotypes+of+the+polycystic+ovary+syndrome.">Divergences in insulin resistance between the different phenotypes of the polycystic ovary syndrome.</a> The Journal of Clinical Endocrinology and Metabolism. 98 (4), 628-637 (2013).</li><li>Ovalle, F., Azziz, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insulin+resistance,+polycystic+ovary+syndrome,+and+type+2+diabetes+mellitus.">Insulin resistance, polycystic ovary syndrome, and type 2 diabetes mellitus.</a> Fertility and Sterility. 77 (6), 1095-1105 (2002).</li><li>Dunaif, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Profound+peripheral+insulin+resistance,+independent+of+obesity,+in+polycystic+ovary+syndrome.">Profound peripheral insulin resistance, independent of obesity, in polycystic ovary syndrome.</a> Diabetes. 38 (9), 1165-1174 (1989).</li><li>Hutchison, S. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+exercise+on+insulin+resistance+and+body+composition+in+overweight+and+obese+women+with+and+without+polycystic+ovary+syndrome.">Effects of exercise on insulin resistance and body composition in overweight and obese women with and without polycystic ovary syndrome.</a> The Journal of Clinical Endocrinology Metabolism. 96 (1), 48-56 (2011).</li><li>Stepto, N. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Women+with+polycystic+ovary+syndrome+have+intrinsic+insulin+resistance+on+euglycaemic-hyperinsulaemic+clamp.">Women with polycystic ovary syndrome have intrinsic insulin resistance on euglycaemic-hyperinsulaemic clamp.</a> Human Reproduction. 28 (3), 777-784 (2013).</li><li>Basu, R., Schwenk, W. F., Rizza, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Both+fasting+glucose+production+and+disappearance+are+abnormal+in+people+with+&amp;#34;mild&amp;#34;+and+&amp;#34;severe&amp;#34;+type+2+diabetes.">Both fasting glucose production and disappearance are abnormal in people with &amp;#34;mild&amp;#34; and &amp;#34;severe&amp;#34; type 2 diabetes.</a> American Journal of Physiology, Endocrinology and Metabolism. 287 (1), 55-62 (2004).</li><li>Blesson, C. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sex+dependent+dysregulation+of+hepatic+glucose+production+in+lean+Type+2+diabetic+rats.">Sex dependent dysregulation of hepatic glucose production in lean Type 2 diabetic rats.</a> Frontiers in Endocrinology. 10, 538 (2019).</li><li>Caldwell, A. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+reproductive,+metabolic,+and+endocrine+features+of+polycystic+ovary+syndrome+in+female+hyperandrogenic+mouse+models.">Characterization of reproductive, metabolic, and endocrine features of polycystic ovary syndrome in female hyperandrogenic mouse models.</a> Endocrinology. 155 (8), 3146-3159 (2014).</li><li>Chappell, N. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prenatal+androgen+induced+lean+PCOS+impairs+mitochondria+and+mRNA+profiles+in+oocytes.">Prenatal androgen induced lean PCOS impairs mitochondria and mRNA profiles in oocytes.</a> Endocrine Connections. 9 (3), 261-270 (2020).</li><li>Chacko, S. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+gluconeogenesis+using+glucose+fragments+and+mass+spectrometry+after+ingestion+of+deuterium+oxide.">Measurement of gluconeogenesis using glucose fragments and mass spectrometry after ingestion of deuterium oxide.</a> Journal of Applied Physiology. 104 (4), 944-951 (2008).</li><li>Bier, D. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+&amp;#34;true&amp;#34;+glucose+production+rates+in+infancy+and+childhood+with+6,6-dideuteroglucose.">Measurement of &amp;#34;true&amp;#34; glucose production rates in infancy and childhood with 6,6-dideuteroglucose.</a> Diabetes. 26 (11), 1016-1023 (1977).</li><li>Chacko, S. K., Sunehag, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gluconeogenesis+continues+in+premature+infants+receiving+total+parenteral+nutrition.">Gluconeogenesis continues in premature infants receiving total parenteral nutrition.</a> Archives of Disease in Childhood. Fetal and Neonatal Edition. 95 (6), 413-418 (2010).</li><li>Chacko, S. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+ghrelin+on+glucose+regulation+in+mice.">Effect of ghrelin on glucose regulation in mice.</a> American Journal of Physiology, Endocrinology and Metabolism. 302 (9), 1055-1062 (2012).</li><li>Marini, J. C., Lee, B., Garlick, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-surgical+alternatives+to+invasive+procedures+in+mice.">Non-surgical alternatives to invasive procedures in mice.</a> Laboratory Animals. 40 (3), 275-281 (2006).</li><li>Jacobs, J. D., Hopper-Borge, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carotid+artery+infusions+for+pharmacokinetic+and+pharmacodynamic+analysis+of+taxanes+in+mice.">Carotid artery infusions for pharmacokinetic and pharmacodynamic analysis of taxanes in mice.</a> Journal of Visualized Experiments: JoVE. (92), e51917 (2014).</li><li>Ayala, J. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperinsulinemic-euglycemic+clamps+in+conscious,+unrestrained+mice.">Hyperinsulinemic-euglycemic clamps in conscious, unrestrained mice.</a> Journal of Visualized Experiments: JoVE. (57), e3188 (2011).</li><li>Kmiotek, E. K., Baimel, C., Gill, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+Intravenous+Self+Administration+in+a+Mouse+Model.">Methods for Intravenous Self Administration in a Mouse Model.</a> Journal of Visualized Experiments: JoVE. (70), e3739 (2012).</li><li>Marini, J. C., Lee, B., Garlick, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+urea+kinetic+studies+in+conscious+mice.">In vivo urea kinetic studies in conscious mice.</a> The Journal of Nutrition. 136 (1), 202-206 (2006).</li><li>Choukem, S. -. P., Gautier, J. -. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+to+measure+hepatic+insulin+resistance.">How to measure hepatic insulin resistance.</a> Diabetes Metabolism. 34 (6), 664-673 (2008).</li></ol>

Hyperglycemia and abnormal glucose metabolism/homeostasis are features of PCOS. Blood glucose level is maintained by a combination of glucose from diet and glucose production via glycogenolysis and gluconeogenesis and glycogenesis, under the control of hormone and enzymes. Hepatic glucose production is suppressed by the presence of increased circulating glucose levels. In disorders of abnormal glucose metabolism, regulation of the suppression of glucose production is compromised leading to hyperglycemia. While m...

Polycystic ovary syndrome (PCOS) is a common disorder occurring in 12%-20% of reproductive-aged women1,2. It is a complex disease resulting in variable phenotypes involving polycystic ovaries, irregular menses and clinical or laboratory evidence of hyperandrogenemia, and is typically diagnosed when a woman meets two of the three criteria3. A predominant aspect of PCOS, and a key factor in its pathogenesis, is metabolic derangements that are found in women who have the disease. Women with PCOS have higher incidences of insulin resistance, glucose intolerance, obesity, and metabolic syndrome3,4,5,6. Insulin resistance is not only a manifestation of the disease, but it is thought to contribute to its pathogenesis by potentiating the action of luteinizing hormone in the ovary thereby leading to increased androgen production7,8. Insulin resistance is thought to have several possible origins but studies suggest it may be due to abnormal patterns of insulin receptor signaling9,10. Studies have evaluated insulin resistance in PCOS patients using the gold standard technique of hyperinsulinemic-euglycemic clamp11,12,13,14,15. Women with PCOS, irrespective of BMI, have higher levels of insulin resistance compared with controls. Insulin control over glucose production is impaired in disorders of insulin resistance leading to excess glucose production. For example, diabetic patients have increased rates of gluconeogenesis and impaired suppression of glycogenolysis16. Furthermore, impaired suppression of glucose production has been observed in diabetic rats17. Although clamp studies can give a measurement of insulin resistance, few studies in PCOS focus on direct measurement of glucose production in fasting and fed states. This requires the use of a non-radioactive isotopic glucose tracer infusion and measurement via mass spectrometry.
Animal models have been extensively used in PCOS research. Both lean and obese-type PCOS murine models have been created by administering androgens prenatally, prepubertally, or post-pubertally18. Rodent PCOS models also demonstrate metabolic differences compared with their respective controls. Previous data from our lab demonstrated abnormal glucose tolerance tests (GTT) in PCOS mouse models (lean and obese), consistent with human PCOS literature19. Use of a lean and obese animal model allows further investigation into metabolic differences. Specifically, this model allows evaluation of the rate of glucose production directly using isotopic glucose tracers. One of the most commonly used stable isotopic glucose tracer is [6,6-2H2]glucose. The [6,6-2H2]glucose enrichment can be measured using a pentaacetate derivative as previously described20.
In this study, our aim was to measure the rate of hepatic glucose production in fasting and glucose-rich state in PCOS mice using isotopic glucose infusion. These techniques can be applied to a wide range of experiments involving glucose kinetics.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.9% sodium chloride solution</td>
			<td>McKesson</td>
			<td>275595</td>
			<td></td>
		</tr>
		<tr>
			<td>10 mL BD Luer-Lok tip syringe</td>
			<td>VWR</td>
			<td>75846-756</td>
			<td>Two syringes per animal (one for isotopic glucose solution, one for glucose-rich isotopic solution)</td>
		</tr>
		<tr>
			<td>1-inch clear transpore tape</td>
			<td>3M</td>
			<td>70200400169</td>
			<td></td>
		</tr>
		<tr>
			<td>1-inch Labeling tape</td>
			<td>Fisher</td>
			<td>GS07F161BA</td>
			<td>Brand is example</td>
		</tr>
		<tr>
			<td>5 mL syringe containing heparanized saline flush</td>
			<td>McKesson</td>
			<td>191-MIH-2235</td>
			<td>One can also prepare a heparin flush solution (10 units/mL heparin in 0.9% sodium chloride)</td>
		</tr>
		<tr>
			<td>5 mm Medipoint Goldenrod animal lancets</td>
			<td>Fisher Scientific</td>
			<td>NC9891620</td>
			<td>5 mm if animal is between 2 and 6 months</td>
		</tr>
		<tr>
			<td>Acetone</td>
			<td>Sigma-Aldrich</td>
			<td>650501</td>
			<td></td>
		</tr>
		<tr>
			<td>Advanced hot plate stirrer</td>
			<td>VWR</td>
			<td>97042-602</td>
			<td>Brand is example</td>
		</tr>
		<tr>
			<td>BD 27 gauge 0.5 inch needles</td>
			<td>Health Warehouse</td>
			<td>A283952</td>
			<td></td>
		</tr>
		<tr>
			<td>BD 30 gauge 0.5 inch needles</td>
			<td>Medvet</td>
			<td>305106</td>
			<td></td>
		</tr>
		<tr>
			<td>BD Intramedic Polyethylene (PE) tubing 0.28 mm ID x 0.61 mm</td>
			<td>VWR</td>
			<td>63019-004</td>
			<td></td>
		</tr>
		<tr>
			<td>BD Intramedic Polyethylene (PE) tubing 0.28 mm ID x 0.61 mm</td>
			<td>VWR</td>
			<td>63019-004</td>
			<td></td>
		</tr>
		<tr>
			<td>Beaker, 1000 mL</td>
			<td></td>
			<td></td>
			<td>Any brand</td>
		</tr>
		<tr>
			<td>Caging pellets</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Clear VOA glass vials with closed-top cap</td>
			<td>Fisher Scientific</td>
			<td>05-719-120</td>
			<td>For storage of acetone and blood draw samples</td>
		</tr>
		<tr>
			<td>Copper toothless alligator clamp for tourniquet</td>
			<td>Amazon</td>
			<td></td>
			<td>Any Brand; smooth toothless alligator clips made of solid copper</td>
		</tr>
		<tr>
			<td>D-(+)-glucose &#62;99.5%</td>
			<td>Sigma-Aldrich</td>
			<td>G8270</td>
			<td></td>
		</tr>
		<tr>
			<td>D-glucose (6,6-D2, 99%)</td>
			<td>Cambridge Isotope Laboratories, Inc.</td>
			<td>DLM-349-PK</td>
			<td></td>
		</tr>
		<tr>
			<td>Dow Corning silastic tubing 0.3 mm ID x 0.64 mm OD</td>
			<td>VWR</td>
			<td>62999-042</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnifying glass</td>
			<td>Amazon</td>
			<td></td>
			<td>Any brand; similar to LANCOSC Magnifying Glass with Light and Stand</td>
		</tr>
		<tr>
			<td>Microbalance</td>
			<td>Ohaus Adventurer Pro</td>
			<td>AV264C</td>
			<td>Any similar model with 0.0001g accuracy can be used</td>
		</tr>
		<tr>
			<td>Nalgene bottle, 500 mL</td>
			<td>Sigma-Aldrich</td>
			<td>B0158-12EA</td>
			<td>Or any Similar brand; saw in half (including lid) and cut tail-sized notch in the bottom</td>
		</tr>
		<tr>
			<td>PHD Ultra multi-syringe pump</td>
			<td>Harvard Apparatus</td>
			<td>70-3024A</td>
			<td></td>
		</tr>
		<tr>
			<td>Plexiglass sheet</td>
			<td></td>
			<td></td>
			<td>Any brand; to stabalize mouse during catheter insertion</td>
		</tr>
		<tr>
			<td>Plexiglass sheets and dividers</td>
			<td></td>
			<td></td>
			<td>Any brand; used to cage mice during infusion</td>
		</tr>
	</tbody>
</table>

evaluation of hepatic glucose production in a polycystic ovary syndrome mouse model

Polycystic ovary syndrome (PCOS) is a common disease that results in disorders of glucose metabolism, such as insulin resistance and glucose intolerance. Dysregulated glucose metabolism is an important manifestation of the disease and is the key to its pathogenesis. Therefore, studies involving evaluation of glucose metabolism in PCOS are of utmost importance. Very few studies have quantified hepatic glucose production directly in PCOS models using non-radioactive glucose tracers. In this study, we discuss step-by-step instructions for the quantification of the rate of hepatic glucose production in a PCOS mouse model by measuring M+2 enrichment of [6,6-2H2]glucose, a stable isotopic glucose tracer, via gas chromatography - mass spectrometry (GCMS). This procedure involves creation of stable isotopic glucose tracer solution, use of tail vein catheter placement and infusion of the glucose tracer in both fasting and glucose-rich states in the same mouse in tandem. The enrichment of [6,6-2H2]glucose is measured using pentaacetate derivative in GCMS. This technique can be applied to a wide variety of studies involving direct measurement of the rate of hepatic glucose production.

Using previously described isotope dilution equations, the total plasma glucose rate (glucoseRa) was calculated from M+2 enrichment of [6,6-2H2]glucose in fasting and glucose-rich conditions using the pentaacetate derivative21. Under steady-state conditions, it is assumed that rate of appearance of glucose is equal to the rate of disappearance of glucose. In the control group, the total glucoseRa was 19.98 &#177; 2.53 mg/(kg&#183;min) after 6 h fasting a...

Watch this Scientific Journal Video about Evaluation of Hepatic Glucose Production in a Polycystic Ovary Syndrome Mouse Model at JoVE.com

Evaluation of Hepatic Glucose Production in a Polycystic Ovary Syndrome Mouse Model

This study describes the direct measurement of hepatic glucose production in a polycystic ovary syndrome mouse model by using a stable isotopic glucose tracer via tail vein in both fasting and glucose-rich states in tandem.

Polycystic ovary syndrome (PCOS) is a common disease that results in disorders of glucose metabolism, such as insulin resistance and glucose intolerance. ...

The goal of this procedure is to determine hepatic glucose production in a polycystic ovary syndrome, or PCOS mouse model. Dysregulated glucose metabolism is an important manifestation of PCOS and is key to its pathogenesis. Therefore, studies involving evaluation of glucose metabolism in PCOS are of utmost importance.In this study, we discuss step-by-step instructions for the quantification of the rate of hepatic glucose production in a PCOS mouse model by measuring the M plus two enrichment of six six deuterated glucose, a stable isotopic glucose tracer, via gas chromatography, mass spectrometry, or GCMS. This procedure of involves creation of a stable isotopic glucose tracer solution, use of tail vein catheter placement and infusion of the glucose tracer in both fasting and glucose-rich states in the same mouse in tandem. One day before the procedure, prepare the stable isotope glucose tracer in normal saline.For this experiment, glucose production during fasting in glucose-rich conditions were measured so the glucose isotope was prepared in two different preparations. The tracer was prepared under sterile conditions by dissolving sterile and pyrogen-free six six deuterated glucose and sterile 0.9%sodium chloride solution with or without glucose. The first infusate was prepared with only the tracer.The second infusate contained both the tracer along with the nonisotopic glucose. Once the solutions were prepared, they were sterile filtered with the 0.22 micron filter and stored at four degrees Celsius. The solutions were prepared in such a way that the final infusing dose was close to one milligram per kilogram and minute and two milligrams per kilogram and minute respectively.For the glucose appearance rate measurement during basal condition in glucose-rich condition, a primed average constant rate infusion of six six deuterated glucose at 1.08 milligrams per kilogram and minute and 1.9 milligrams per kilogram in minute respectively were used. In order to mimic fed state, we employed an average D-glucose infusion rate of 18.8 milligrams per kilogram and minute during glucose-rich condition. Remove the mice from their home cages, and place them in their fasting cages three hours prior to the start of the experiment.For this experiment, we used four month-old female mice from the C57BL6J strain. Assemble the caging equipment by grouping the mice into a set number of mice per insulin pump. Place partitions on top of a flat, stable base to make individual stalls for the mice.Cages are clear and made out of plexiglass. There is a flat, stable base upon which the partitions sit. The door to the cage slides to close and has a notch at the bottom to allow the tail to fit through.Assemble the syringes containing one milliliter of basal infusate, then connect to infusion pump tubing using the polyethylene tubing. Prepare the infusion pump by setting the rate to 150 microliters an hour, which is the basal rate. Heat a water bath to 48 degrees Celsius.Prepare the catheter insertion station adjacent to the water bath containing the 30 gauge half-inch needles, silastic tubing, and one-inch, clear transport tape. Select one mouse and place it in a secure holder with access to the tail. Place a piece of tape over the proximal portion of the tail to allow space for the catheter insertion more distally.Bring the mouse to the water bath, and insert the tail in the water bath for approximately 30 to 45 seconds. This helps to dilate the tail vasculature for catheter placement. The catheter insertion must be done under sterile conditions.Once the tail's warmed, clean the tail, and place a small copper toothless alligator clamp as a tourniquet at the proximal end of the tail. Visualize the lateral tail vein under a magnifying glass. Then, carefully insert the catheter into the tail vein, and flush the solution gently to ensure patency of the catheter.Wrap a piece of transport tape around insertion site to secure the catheter, and remove the small tourniquet from the tail. Place the mouse in its individual cage and close the sliding door, ensuring that the tail's protruding through the notch and remains outside of the cage. Place an additional piece of tape over the whole catheter and the tail to secure it to the base plate of the cage.Disconnect the flush from the tail vein catheter, and place the small clamp on the catheter's silastic tubing to prevent backflow while connecting the infusate line from the pump. Once securely connected, remove the clamp and flush the priming solution which consists of the infusate. Ensure that the solution is clear in the tube and not blood-stained.Once infusion lines are noted to be functioning properly, remove the cover from the mouse. Place standard bedding around the mouse. Start the infusion with the infusate containing the tracer, and run it for three hours continuously.For the duration of the infusion, continue to check mice well-being, as well as the infusion lines. Ensure that the infusion tubing is properly secured and that there's no leaks from the line connection points. After the first infusion has completed, stop the infusion and place a clamp on the tubing of the catheter to prevent backflow.Gently removed the mice from their enclosures without disturbing the catheter in order to collect blood. For this experiment, the mice underwent cheek vein puncture using a four millimeter lancet. Collect approximately 75 microliters of blood into your desired vial.To deproteinize samples in preparation for mass spectrometry, add approximately 15 microliters of blood to 500 microliters of acetone. Remaining blood can be used to check blood glucose level via glucometer and/or a centrifuge to separate plasma for future hormone assays. Remove the infusate from the syringe pumps by disconnecting the tubing from the syringes, and replace it with the second infusate containing tracer along with glucose.Repeat previous infusion steps using the glucose-rich isotopic glucose infusion. To reach steady state, run a bolus of the second infusate at 600 microliters an hour for 15 minutes. Note the starting time for each group of cages.Decrease the infusion rate to 150 microliters an hour to complete the three hours of total infusion time. Repeat blood sampling as previously described. Disconnect infusions, apply pressure at the catheter sites until the bleeding stops, and return the mice to their home cages.Next, the samples are sent for GCMS. Calculate the isotopic enrichment of the glucose isotope under glucose peak by GCCMS using the pentaacetate derivative. Briefly, this method involves preparation of the pentaacetate derivative of glucose, followed by sample analysis using GCMS in the positive chemical ionization mode.Selective ion monitoring of the mass-to-charge ratio, 171 to 169, is performed to determine the M plus two enrichment of the glucose isotope. All kinetic measurements are performed assuming steady state conditions. Calculate total plasma glucose appearance rate from the M plus two enrichment of the glucose isotope and plasma using established isotope dilution equations.Under steady state conditions, it is assumed that the rate of appearance of glucose is equal to the rate of disappearance of glucose. Rate of endogenous glucose production equals total plasma glucose rate minus exogenous glucose. Table one includes the representative results from the study.All units are expressed as milligram per kilogram and minute. Using previously described isotope dilution equations, total plasma glucose rate was calculated. In the control group, the mean glucose rate of appearance was 19.98 in the fasting state.In glucose-rich conditions, the glucose rate of appearance was 25.8. Glucose production rate was 19.08 in the fasting state and 8.56 in the glucose-rich state. Abnormal glucose metabolism and homeostasis are common in PCOS.In disorders of abnormal glucose metabolism, regulation of the suppression of glucose production is compromised leading to hyperglycemia. In this study, we describe a straightforward way to measure the rate of hepatic glucose production in multiple mice at the same time. The critical components of this experiment are the catheter insertion and defining the exact measurements of the glucose isotope and natural glucose in order to adequately perform GCMS.The advantages of the study is accomplishing the infusion in a minimally invasive fashion due to tail vein catheter insertion, as well as use of an easily attainable, stable glucose tracer. There are some limitations to the study, including the technical demand of the procedure and need for possible additional skills. Overall, we describe a straightforward, accurate way to measure the rate of total hepatic glucose production in a PCOS mouse model.This technique could serve as the foundation for multiple studies involving glucose metabolism of mouse models.

evaluation-hepatic-glucose-production-polycystic-ovary-syndrome-mouse

Research

JoVE Journal

Medicine

Murine Bioluminescent Hepatic Tumour Model

This video describes the establishment of liver metastases in a mouse model that can be subsequently analysed by bioluminescent imaging. Tumour cells are administered specifically to the liver to induce a localised liver tumour, via mobilisation of the spleen and splitting into two, leaving intact the vascular pedicle for each half of the spleen. Lewis lung carcinoma cells that constitutively express the firefly luciferase gene (luc1) are inoculated into one hemi-spleen which is then resected 10 minutes later. The other hemi-spleen is left intact and returned to the abdomen. Liver tumour growth can be monitored by bioluminescence imaging using the IVIS whole body imaging system. Quantitative imaging of tumour growth using IVIS provides precise quantitation of viable tumour cells. Tumour cell death and necrosis due to drug treatment is indicated early by a reduction in the bioluminescent signal. This mouse model allows for investigating the mechanisms underlying metastatic tumour-cell survival and growth and can be used for the evaluation of therapeutics of liver metastasis. 

This article describes a procedure for the induction of orthotopic bioluminescent liver tumours in mice, and subsequent analysis of tumour growth confined to the liver using live whole body luminescence imaging.

This video describes the establishment of liver metastases in a mouse model that can be subsequently analysed by bioluminescent imaging. Tumour cells are ...

A Preclinical Murine Model of Hepatic Metastases

Numerous murine models have been developed to study human cancers and advance the understanding of cancer treatment and development. Here, a preclinical, murine pancreatic tumor model of hepatic metastases via a hemispleen injection of syngeneic murine pancreatic tumor cells is described. This model mimics many of the clinical conditions in patients with metastatic disease to the liver. Mice consistently develop metastases in the liver allowing for investigation of the metastatic process, experimental therapy testing, and tumor immunology research.

A preclinical, murine model of hepatic metastases performed via a hemispleen injection technique.

Numerous murine models have been developed to study human cancers and advance the understanding of cancer treatment and development. Here, a preclinical, ...

A Possible Zebrafish Model of Polycystic Kidney Disease: Knockdown of wnt5a Causes Cysts in Zebrafish Kidneys

Polycystic kidney disease (PKD) is one of the most common causes of end-stage kidney disease, a devastating disease for which there is no cure. The molecular mechanisms leading to cyst formation in PKD remain somewhat unclear, but many genes are thought to be involved. Wnt5a is a non-canonical glycoprotein that regulates a wide range of developmental processes. Wnt5a works through the planar cell polarity (PCP) pathway that regulates oriented cell division during renal tubular cell elongation. Defects of the PCP pathway have been found to cause kidney cyst formation. Our paper describes a method for developing a zebrafish cystic kidney disease model by knockdown of the wnt5a gene with wnt5a antisense morpholino (MO) oligonucleotides. Tg(wt1b:GFP) transgenic zebrafish were used to visualize kidney structure and kidney cysts following wnt5a knockdown. Two distinct antisense MOs (AUG - and splice-site) were used and both resulted in curly tail down phenotype and cyst formation after wnt5a knockdown. Injection of mouse Wnt5a mRNA, resistant to the MOs due to a difference in primary base pair structure, rescued the abnormal phenotype, demonstrating that the phenotype was not due to &#8220;off-target&#8221; effects of the morpholino. This work supports the validity of using a zebrafish model to study wnt5a function in the kidney.

A Possible Zebrafish Model of Polycystic Kidney Disease: Knockdown of wnt5a Causes Cysts in Zebrafish Kidneys

We describe a method of generating a possible zebrafish model of polycystic kidney disease. We used Tg(wt1b:GFP) fish to visualize kidney structure. Knockdown of wnt5a was by morpholino injection. Pronephric cyst formation after wnt5a knockdown was observed in this GFP transgenic zebrafish.

Polycystic kidney disease (PKD) is one of the most common causes of end-stage kidney disease, a devastating disease for which there is no cure. The ...

Invasive Hemodynamic Characterization of the Portal-hypertensive Syndrome in Cirrhotic Rats

This is a detailed protocol describing invasive hemodynamic measurements in cirrhotic rats for the characterization of portal hypertensive syndrome. Portal hypertension (PHT) due to cirrhosis is responsible for the most severe complications in patients with liver disease. The full picture of the portal hypertensive syndrome is characterized by increased portal pressure (PP) due to the increased intrahepatic vascular resistance (IHVR), hyperdynamic circulation, and increased splanchnic blood flow. Progressive splanchnic arterial vasodilation and increased cardiac output with elevated heart rate (HR) but low arterial pressure characterizes the portal hypertensive syndrome.
Novel therapies are currently being developed that aim to decrease PP by either targeting IHVR or increased splanchnic blood flow &#8212; but side effects on systemic hemodynamics may occur. Thus, a detailed characterization of portal venous, splanchnic, and systemic hemodynamic parameters, including measurement of PP, portal venous blood flow (PVBF), mesenteric arterial blood flow, mean arterial pressure (MAP), and HR is needed for preclinical evaluation of the efficacy of novel treatments for PHT. Our video article provides the reader with a structured protocol for performing invasive hemodynamic measurements in cirrhotic rats. In particular, we describe the catheterization of the femoral artery and the portal vein via an ileocolic vein and the measurement of portal venous and splanchnic blood flow via perivascular Doppler-ultrasound flow probes. Representative results of different rat models of PHT are shown.

Here we describe a detailed protocol for invasive measurements of hemodynamic parameters including portal pressure, splanchnic blood flow, and systemic hemodynamics in order to characterize the portal hypertensive syndrome in rats.

This is a detailed protocol describing invasive hemodynamic measurements in cirrhotic rats for the characterization of portal hypertensive syndrome. ...

Oleic Acid-Injection in Pigs As a Model for Acute Respiratory Distress Syndrome

The acute respiratory distress syndrome is a relevant intensive care disease with an incidence ranging between 2.2% and 19% of intensive care unit patients. Despite treatment advances over the last decades, ARDS patients still suffer mortality rates between 35 and 40%. There is still a need for further research to improve the outcome of patients suffering from ARDS. One problem is that no single animal model can mimic the complex pathomechanism of the acute respiratory distress syndrome, but several models exist to study different parts of it. Oleic acid injection (OAI)-induced lung injury is a well-established model for studying ventilation strategies, lung mechanics and ventilation/perfusion distribution in animals. OAI leads to severely impaired gas exchange, deterioration of lung mechanics and disruption of the alveolo-capillary barrier. The disadvantage of this model is the controversial mechanistic relevance of this model and the necessity for central venous access, which is challenging especially in smaller animal models. In summary, OAI-induced lung injury leads to reproducible results in small and large animals and hence represents a well-suited model for studying ARDS. Nevertheless, further research is necessary to find a model that mimics all parts of ARDS and lacks the problems associated with the different models existing today.

In this article, we present a protocol to induce acute lung injury in pigs by central-venous injection of oleic acid. This is an established animal model for studying the acute respiratory distress syndrome (ARDS).

The acute respiratory distress syndrome is a relevant intensive care disease with an incidence ranging between 2.2% and 19% of intensive care unit ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...

Standardized Histomorphometric Evaluation of Osteoarthritis in a Surgical Mouse Model

One of the most prevalent joint disorders in the United States, osteoarthritis (OA) is characterized by progressive degeneration of articular cartilage, primarily in the hip and knee joints, which results in significant impacts on patient mobility and quality of life. To date, there are no existing curative therapies for OA able to slow down or inhibit cartilage degeneration. Presently, there is an extensive body of ongoing research to understand OA pathology and discover novel therapeutic approaches or agents that can efficiently slow down, stop, or even reverse OA. Thus, it is crucial to have a quantitative and reproducible approach to accurately evaluate OA-associated pathological changes in the joint cartilage, synovium, and subchondral bone. Currently, OA severity and progression are primarily assessed using the Osteoarthritis Research Society International (OARSI) or Mankin scoring systems. In spite of the importance of these scoring systems, they are semiquantitative and can be influenced by user subjectivity. More importantly, they fail to accurately evaluate subtle, yet important, changes in the cartilage during the early disease states or early treatment phases. The protocol we describe here uses a computerized and semiautomated histomorphometric software system to establish a standardized, rigorous, and reproducible quantitative methodology for the evaluation of joint changes in OA. This protocol presents a powerful addition to the existing systems and allows for more efficient detection of pathological changes in the joint.

The current protocol establishes a rigorous and reproducible method for quantification of morphological joint changes that accompany osteoarthritis. Application of this protocol can be valuable in monitoring disease progression and evaluating therapeutic interventions in osteoarthritis.

One of the most prevalent joint disorders in the United States, osteoarthritis (OA) is characterized by progressive degeneration of articular cartilage, ...

Retinal Pathophysiological Evaluation in a Rat Model

A posterior segment eye disease like diabetic retinopathy alters the physiology of the retina. Diabetic retinopathy is characterized by a retinal detachment, breakdown of the blood-retinal barrier (BRB), and retinal angiogenesis. An in vivo rat model is a valuable experimental tool to examine the changes in the structure and function of the retina. We propose three different experimental techniques in the rat model to identify morphological changes of retinal cells, retinal vasculature, and compromised BRB. Retinal histology is used to study the morphology of various retinal cells. Also, quantitative measurement is performed by retinal cell count and thickness measurement of different retinal layers. A BRB breakdown assay is used to determine the leakage of extraocular proteins from the plasma to vitreous tissue due to the breakdown of BRB. Fluorescence angiography is used to study angiogenesis and leakage of blood vessels by visualizing retinal vasculature using FITC-dextran dye.

Diabetic retinopathy is one of the leading causes of blindness. Histology, blood-retinal barrier breakdown assay, and fluorescence angiography are valuable techniques to understand the pathophysiology of the retina, which could further enhance the efficient drug screening against diabetic retinopathy.

A posterior segment eye disease like diabetic retinopathy alters the physiology of the retina. Diabetic retinopathy is characterized by a retinal ...

A Neonatal BALB/c Mouse Model of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is the most severe gastrointestinal (GI) disease that often occurs in premature infants, especially very low birth weight infants, with high mortality and unclear pathogenesis. The cause of NEC may be related to inflammatory immune regulatory system abnormalities. An NEC animal model is an indispensable tool for NEC disease immune research. NEC animal models usually use C57BL/6J neonatal mice; BALB/c neonatal mice are rarely used. Related studies have shown that when mice are infected, Th2 cell differentiation is predominant in BALB/c mice compared to C57BL/6J mice. Studies have suggested that the occurrence and development of NEC are associated with an increase in T helper type 2 (Th2) cells and are generally accompanied by infection. Therefore, this study used neonatal BALB/c mice to induce an NEC model with similar clinical characteristics and intestinal pathological changes as those observed in children with NEC. Further study is warranted to determine whether this animal model could be used to study Th2 cell responses in NEC.

Necrotizing enterocolitis (NEC) is the most severe gastrointestinal (GI) disease that often occurs in premature infants, especially very low birth weight infants, with high mortality and unclear pathogenesis. The cause of NEC may be related to inflammatory immune regulatory system abnormalities. An NEC animal model is an indispensable tool for NEC disease immune research. NEC animal models usually use C57BL/6J neonatal mice; BALB/c neonatal mice are rarely used. Related studies have shown that when mice are infected, Th2 cell differentiation is predominant in BALB/c mice compared to C57BL/6J mice. Studies have suggested that the occurrence and development of NEC are associated with an increase in T helper type 2 (Th2) cells and are generally accompanied by infection. Therefore, this study used neonatal BALB/c mice to induce an NEC model with similar clinical characteristics and intestinal pathological changes as those observed in children with NEC. Further study is warranted to determine whether this animal model could be used to study Th2 cell responses in NEC.

Necrotizing enterocolitis (NEC) is the most severe gastrointestinal (GI) disease that often occurs in premature infants, especially very low birth weight ...

HE Staining and Micro-CT to Evaluate Murine Trabecular Bone Microarchitecture

Trabecular Bone Microarchitecture Evaluation in an Osteoporosis Mouse Model

Bone microstructure refers to the arrangement and quality of bone tissue at the microscopic level. Understanding the bone microstructure of the skeleton is crucial for gaining insight into the pathophysiology of osteoporosis and improving its treatment. However, handling bone samples can be complex due to their hard and dense properties. Secondly, specialized software makes image processing and analysis difficult. In this protocol, we present a cost-effective and easy-to-use solution for trabecular bone microstructure analysis. Detailed steps and precautions are provided. Micro-CT is a non-destructive three-dimensional (3D) imaging technique that provides high-resolution images of trabecular bone structure. It allows for the objective and quantitative evaluation of bone quality, which is why it is widely regarded as the gold standard method for bone quality assessment. However, histomorphometry remains indispensable as it offers crucial cellular-level parameters, bridging the gap between two-dimensional (2D) and 3D assessments of bone specimens. As for the histologic techniques, we chose to decalcify the bone tissue and then perform traditional paraffin embedding. In summary, combining these two methods can provide more comprehensive and accurate information on bone microstructure.

Author Spotlight: An Economic and Efficient Method for Quantitative Evaluation of Bone Microarchitecture in a Murine Osteoporosis Model 

This protocol presents an economical and efficient method for quantitative evaluation of bone microarchitecture in a mouse model of osteoporosis by combining Hematoxylin-Eosin (HE) staining and micro-computed tomography (Micro-CT) techniques.

Bone microstructure refers to the arrangement and quality of bone tissue at the microscopic level. Understanding the bone microstructure of the skeleton ...