Name: a rat model of mild intrauterine hypoperfusion with microcoil stenosis
Uploaded: 2018-01-07T14:00:00
Description: Watch this Scientific Journal Video about A Rat Model of Mild Intrauterine Hypoperfusion with Microcoil Stenosis at JoVE.com

This work was supported by the FY 2013 Research Exchange Program between JSPS and CNRS, JSPS KAKENHI Grant Number 26860858, and the Narishige Neuroscience Research Foundation. We thank Drs. Mariko Harada-Shiba and Kyoko Shioya for helpful discussions. We thank Mari Furuta, Mutsumi Sakamoto, Ritsuko Maki, and Dr. Emi Tanaka for excellent technical assistance.

All experiments were performed in accordance with protocols approved by the Experimental Animal Care and Use Committee of the National Cerebral and Cardiovascular Center, Suita, Japan.
1. Prepare the following animals and materials for MIUH surgery
<ol>
	<li>Prepare timed pregnant Sprague-Dawley rats at gestational day 17, i.e., embryonic day 17 (E17). The dams&#39; average body weights are 307.0 &#177; 40.7 g (mean &#177; SD, n = 9).</li>
	<li>Prepare metal microcoils; inner diamet...

<ol>
	<li>Ohshima, 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=Mild+intrauterine+hypoperfusion+reproduces+neurodevelopmental+disorders+observed+in+prematurity.">Mild intrauterine hypoperfusion reproduces neurodevelopmental disorders observed in prematurity.</a> Sci Rep. 6, 39377 (2016).</li><li>Anderson, P., Doyle, L. W., Victorian Infant Collaborative Study, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurobehavioral+outcomes+of+school-age+children+born+extremely+low+birth+weight+or+very+preterm+in+the+1990s.">Neurobehavioral outcomes of school-age children born extremely low birth weight or very preterm in the 1990s.</a> JAMA. 289 (24), 3264-3272 (2003).</li><li>Levine, T. 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=Early+childhood+neurodevelopment+after+intrauterine+growth+restriction:+a+systematic+review.">Early childhood neurodevelopment after intrauterine growth restriction: a systematic review.</a> Pediatrics. 135 (1), 126-141 (2015).</li><li>Sucksdorff, 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=Preterm+Birth+and+Poor+Fetal+Growth+as+Risk+Factors+of+Attention-Deficit/+Hyperactivity+Disorder.">Preterm Birth and Poor Fetal Growth as Risk Factors of Attention-Deficit/ Hyperactivity Disorder.</a> Pediatrics. 136 (3), e599-e608 (2015).</li><li>Volpe, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brain+injury+in+premature+infants:+a+complex+amalgam+of+destructive+and+developmental+disturbances.">Brain injury in premature infants: a complex amalgam of destructive and developmental disturbances.</a> Lancet Neurol. 8 (1), 110-124 (2009).</li><li>Nardozza, L. 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=Fetal+growth+restriction:+current+knowledge.">Fetal growth restriction: current knowledge.</a> Arch Gynecol Obstet. 295 (5), 1061-1077 (2017).</li><li>Chang, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preterm+birth+and+the+role+of+neuroprotection.">Preterm birth and the role of neuroprotection.</a> Bmj. 350, g6661 (2015).</li><li>Coq, J. O., Delcour, M., Massicotte, V. S., Baud, O., Barbe, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prenatal+ischemia+deteriorates+white+matter,+brain+organization,+and+function:+implications+for+prematurity+and+cerebral+palsy.">Prenatal ischemia deteriorates white matter, brain organization, and function: implications for prematurity and cerebral palsy.</a> Dev Med Child Neurol. 58, 7-11 (2016).</li><li>Jantzie, L. L., Corbett, C. J., Firl, D. J., Robinson, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postnatal+Erythropoietin+Mitigates+Impaired+Cerebral+Cortical+Development+Following+Subplate+Loss+from+Prenatal+Hypoxia-Ischemia.">Postnatal Erythropoietin Mitigates Impaired Cerebral Cortical Development Following Subplate Loss from Prenatal Hypoxia-Ischemia.</a> Cereb Cortex. 25 (9), 2683-2695 (2015).</li><li>Kubo, K. I., 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=Association+of+impaired+neuronal+migration+with+cognitive+deficits+in+extremely+preterm+infants.">Association of impaired neuronal migration with cognitive deficits in extremely preterm infants.</a> JCI Insight. 2 (10), (2017).</li><li>Delcour, 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=Mild+musculoskeletal+and+locomotor+alterations+in+adult+rats+with+white+matter+injury+following+prenatal+ischemia.">Mild musculoskeletal and locomotor alterations in adult rats with white matter injury following prenatal ischemia.</a> Int J Dev Neurosci. 29 (6), 593-607 (2011).</li><li>Gilbert, J. S., Babcock, S. A., Granger, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypertension+produced+by+reduced+uterine+perfusion+in+pregnant+rats+is+associated+with+increased+soluble+fms-like+tyrosine+kinase-1+expression.">Hypertension produced by reduced uterine perfusion in pregnant rats is associated with increased soluble fms-like tyrosine kinase-1 expression.</a> Hypertension. 50 (6), 1142-1147 (2007).</li><li>Granger, J. 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=Reduced+uterine+perfusion+pressure+(RUPP)+model+for+studying+cardiovascular-renal+dysfunction+in+response+to+placental+ischemia.">Reduced uterine perfusion pressure (RUPP) model for studying cardiovascular-renal dysfunction in response to placental ischemia.</a> Methods Mol Med. 122, 383-392 (2006).</li><li>Mazur, M., Miller, R. H., Robinson, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postnatal+erythropoietin+treatment+mitigates+neural+cell+loss+after+systemic+prenatal+hypoxic-ischemic+injury.">Postnatal erythropoietin treatment mitigates neural cell loss after systemic prenatal hypoxic-ischemic injury.</a> J Neurosurg Pediatr. 6 (3), 206-221 (2010).</li><li>Olivier, P., Baud, O., Evrard, P., Gressens, P., Verney, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prenatal+ischemia+and+white+matter+damage+in+rats.">Prenatal ischemia and white matter damage in rats.</a> J Neuropathol Exp Neurol. 64 (11), 998-1006 (2005).</li><li>Robinson, 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=Developmental+changes+induced+by+graded+prenatal+systemic+hypoxic-ischemic+insults+in+rats.">Developmental changes induced by graded prenatal systemic hypoxic-ischemic insults in rats.</a> Neurobiol Dis. 18 (3), 568-581 (2005).</li><li>Rice, D., Barone, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Critical+periods+of+vulnerability+for+the+developing+nervous+system:+evidence+from+humans+and+animal+models.">Critical periods of vulnerability for the developing nervous system: evidence from humans and animal models.</a> Environ Health Perspect. 108, 511-533 (2000).</li><li>Basilious, A., Yager, J., Fehlings, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurological+outcomes+of+animal+models+of+uterine+artery+ligation+and+relevance+to+human+intrauterine+growth+restriction:+a+systematic+review.">Neurological outcomes of animal models of uterine artery ligation and relevance to human intrauterine growth restriction: a systematic review.</a> Dev Med Child Neurol. 57 (5), 420-430 (2015).</li><li>Delcour, 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=Neuroanatomical,+sensorimotor+and+cognitive+deficits+in+adult+rats+with+white+matter+injury+following+prenatal+ischemia.">Neuroanatomical, sensorimotor and cognitive deficits in adult rats with white matter injury following prenatal ischemia.</a> Brain Pathol. 22 (1), 1-16 (2012).</li></ol>

The microcoil stenosis of both ovarian and uterine arteries in both uterine horns produces consistent and reproducible intrauterine hypoperfusion in all placentas and fetuses. The level of hypoperfusion can be modified by using microcoils with different inner diameters. Rat pups born from a dam on which artery stenosis has been performed with microcoils 0.24 mm in inner diameter demonstrate IUGR and premature birth (see reference 1 for details). The pups exhibit neuroanatomical and behavioral alterations that resemble th...

Infants with intrauterine growth restriction (IUGR) (also known as fetal growth restriction) (birth weight &#60;10th percentile for gestational age), preterm birth (born at &#60; 37 weeks of gestation), and/or low birth weight (&#60; 2500 g) account for nearly 10% of all newborns 2,3. Many of these infants present with neurological problems such as cerebral palsy and developmental disorders (e.g., attention-deficit/hyperactivity disorder (ADHD) and learning disorders) 3,4,5. Those conditions have similarities and differences in their etiology and outcomes. The etiology of IUGR is multifactorial, and placental insufficiency associated with intrauterine hypoperfusion is considered to be the most common cause in non-anomalous fetuses 7. The etiology of preterm is multifactorial as well, and chorioamnionitis is the most frequent cause 8.
The influence of mild intrauterine hypoperfusion (MIUH) on the developing brain is unclear. Currently available animal models of intrauterine hypoperfusion/ischemia primarily involve either severe hypoperfusion or gradient degree of hypoperfusion with or without reperfusion 9,10,11. In clinical settings, however, cases of MIUH are considered to be far more frequent than those involving such severe conditions. The currently available models of MIUH are a rodent model involving suture ligation of either the uterine or the ovarian artery and a rodent model involving clipping the bilateral ovarian arteries and aorta having patency 12,13,14,15,16,17. One of the disadvantages of these models is the extensive inter-fetus variability, ranging from fetuses with profound hypoperfusion to fetuses with nearly intact perfusion, depending on the position of the fetus within the arterial arcade of the uterine and ovarian arteries. Another disadvantage of these models is their inability to distinguish the position of each fetus after birth; hence, researchers cannot distinguish the severity of intrauterine hypoperfusion experienced by an individual pup after its birth.
We have developed a rat model of MIUH involving multiple artery stenosis 1. Wrapping metal micro-coils with an inner diameter of 0.24 mm around the ovarian and uterine arteries causes stenosis, but not obstruction, of the blood vessels (Figure 1). Applying these microcoils at the proximal parts of all of the arteries supplying the uterus, i.e., the bilateral uterine and ovarian arteries, on embryonic day 17 (equivalent to embryonic weeks 20-25 in humans 18) induces a significant but mild decrease in blood flow to the placentas and fetuses. The decreases in blood flow after coils are applied to all four arteries feeding the uterus are largely the same across each placenta and fetus. The fetus mortality rate is less than 20%. The pups are born via spontaneous labor 1-2 days earlier (embryonic day 21-22) than normal. Almost all pups are born exhibiting significantly low birth weights 1. Gray and white matter volumes are decreased without obvious tissue damage 1. Pups present with delayed acquisition of newborn reflexes, muscle weakness, and altered spontaneous activity 1. This model mimics the clinical signs and symptoms of children born prematurely or with IUGR; children born preterm exhibit reduced gray and white matter volume with or without white matter injury 6, present delayed milestones of neurological development, and may present behavioral problems such as ADHD 3,5; children with IUGR exhibit minimal neuroanatomical alterations, and have an increased risk of impaired neurological development such as motor and cognitive delay 4,7. Preterm birth and IUGR are different conditions, but the two conditions share the basic mechanism, i.e. insults to immature brains before full-term gestational age.

<table>
	<tbody>
		<tr>
			<td>Stereomicroscope</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane anesthesia machine</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthesia induction box</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Heating pad</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Diaper 30x40 cm</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Depilatory foam or shaver</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Iodine disinfectant solution</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gauze 10x20 cm&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical drape 45x45 cm with a round opening 5 cm in diameter</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Spray bottle with ethanol for disinfection</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cotton swab</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Forceps with large blunt tips</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Forceps with angled fine tips</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Scissors</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical scalpel, blade size is 27mm long (no.10, Axel, AS ONE Corporation, Osaka, Japan)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical suture needle</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Metal microcoils; inner diameter 0.24 mm, made from gold-coated steel (SAMINI Co. Ltd., Shizuoka, Japan)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Silk suture 4-0</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile saline (0.9% sodium chloride)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Heating water bath</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Plastic syringes (50ml) and needles (18G)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

a rat model of mild intrauterine hypoperfusion with microcoil stenosis

Intrauterine hypoperfusion/ischemia is one of the major causes of intrauterine/fetal growth restriction, preterm birth, and low birth weight. Most studies of this phenomenon have been performed in either models with severe intrauterine ischemia or models with gradient degree of intrauterine hypoperfusion. No study has been performed in a model on uniform mild intrauterine hypoperfusion (MIUH). Two models have been used for studies of MIUH: a model based on suture ligation of either side of the arterial arcade formed with the uterine and ovarian arteries, and a transient model based on clipping the bilateral ovarian arteries and aorta having patency. Those two rodent models of MIUH have some limitations, e.g., not all fetuses are subjected to MIUH, depending on their position in the uterine horn. In our MIUH model, all fetuses are subjected to a comparable level of intrauterine hypoperfusion. MIUH was achieved by mild stenosis of all four arteries feeding the uterus, i.e., the bilateral uterine and ovarian arteries.
Arterial stenosis was induced by metal microcoils wrapped around the feeding arteries. Producing arterial stenosis with microcoils allowed us to control, optimize, and reproduce decreased blood flow with very little inter-animal variability and a low mortality rate, thus enabling accurate evaluation. When microcoils with an inner diameter of 0.24 mm were used, the blood flow in both the placenta and fetus was mildly decreased (approximately 30% from the pre-stenosis level in the placenta). The offspring of our MIUH model clearly demonstrates long-lasting alterations in neurological, neuroanatomical and behavioral test results.

After applying microcoils to all of the arteries feeding the uterus, i.e., the bilateral uterine and ovarian arteries, all fetuses are subjected to comparable levels of hypoperfusion. The application of microcoils with an inner diameter of 0.24 mm causes mild stenosis of those arteries, thereby causing a mild decrease in blood flow to the placentas and fetuses (Figure 3; approximately 30% from the pre-stenosis level in the placenta, see reference 1 for detail...

Watch this Scientific Journal Video about A Rat Model of Mild Intrauterine Hypoperfusion with Microcoil Stenosis at JoVE.com

A Rat Model of Mild Intrauterine Hypoperfusion with Microcoil Stenosis

Mild intrauterine hypoperfusion was produced by artery stenosis with metal microcoils wrapped around the uterine and ovarian arteries in rats at embryonic day 17. This procedure produced prenatal hypoperfusion and intrauterine growth restriction.

Intrauterine hypoperfusion/ischemia is one of the major causes of intrauterine/fetal growth restriction, preterm birth, and low birth weight. Most studies ...

The overall goal of this surgical intervention is to use metal microcoils, wrapped around both uterine and ovarian arteries, to induce artery stenosis for the generation of mild intrauterine hypoperfusion. This method can help answer key questions in the fetal brain injury field, such as, how does mild intrauterine hypoperfusion influence neural development later in life? The main advantage of this technique is that an entire litter of fetuses can be subjected to an equal degree of mild hypoperfusion at the same time.On embryonic day 17, place an anesthetized, pregnant rat dam in the supine position on a sterile diaper placed on top of a heating pad. Confirm a lack of response to toe pinch and apply ointment to the animal's eyes. Remove the hair from the navel area to the pelvic arch, and use an iodine soaked gauze, soaked to disinfect the exposed skin.Place a sterile drape over the animal with the round opening over the surgical area, and use a scalpel to make an approximately 2.5 centimeter skin incision in the lower abdomen, from the upper edge of the public bone toward the navel. Make a secondary incision through the corresponding muscle layer and place several pieces of sterile gauze around the opening of the drape. Wet the gauze with 37 degree Celsius saline and gently push both lateral sides of the abdomen until a portion of uterine horn emerges from the incision.Using 70%ethanol-sterilized fingers, gently remove one entire uterine horn from the abdominal cavity and place the horn on the wet gauze. After removing the second uterine horn, apply 37 degree Celsius saline to keep the horns warm and place the animal under a stereo microscope. Keeping the uterus warm and wet throughout the procedure is critical.Otherwise, many fetuses may be lost before delivery. Locate the proximal region of the main arcade of the ovarian and uterine arteries, and use forceps to separate the artery from the vein running parallel to the artery. It is essential for a successful procedure to identify the proximal portion of the main arcade of the ovarian and uterine arteries, which is small in diameter but has numerous branches to the placentas.Place a 5 centimeter long piece of 4-0 silk suture under the artery and lift both ends of the suture with the forceps until the artery is separated from the vein. Using fine forceps, place a gold-coated steel microcoil next to the lifted artery and use the suture to rotate the artery three or four turns around the microcoil. Then, grasp the coil with the fine forceps at the wrapped end and wrap the artery around the naked end of the coil as just demonstrated.After wrapping the three other arteries with microcoils in the same manner, gently return the uterine horn to the abdominal cavity and use interrupted single 4-0 silk sutures to individually close the muscle and skin layers. Then, allow the rat to recover in a warmed cage with monitoring until full recovery. Applying microcoils to the bilateral uterine and ovarian arteries causes a mild stenosis of the arteries and a mild decrease in blood flow to all of the placentas and fetuses.Each fetus is then subjected to similar levels of hypoperfusion, approximately 30%from pre-stenosis level in the placenta, resulting in the consequent development of intrauterine growth-restricted pups. After its development, this technique paved the way for researchers in the field of brain injury to explore the inference of mild intrauterine hypoperfusion in a prenatal rodent.

a-rat-model-of-mild-intrauterine-hypoperfusion-with-microcoil-stenosis

Research

JoVE Journal

Neuroscience

A Protocol for Measuring Cue Reactivity in a Rat Model of Cocaine Use Disorder

Cocaine use disorder (CUD) follows a trajectory of repetitive self-administration during which previously neutral stimuli gain incentive value. Cue reactivity, the sensitivity to cues previously linked with the drug-taking experience, plays a prominent role in human craving during abstinence. Cue reactivity can be assessed as the attentional orientation toward drug-associated cues that is measurable as appetitive approach behavior in both preclinical and human studies. Herein describes an assessment of cue reactivity in rats trained to self-administer cocaine. Cocaine self-administration is paired with the presentation of discrete cues that act as conditioned reinforcers (i.e., house light, stimulus light, infusion pump sounds). Following a period of abstinence, lever presses in the cocaine self-administration context accompanied by the discrete cues previously paired with cocaine infusion are measured as cue reactivity. This model is useful to explore neurobiological mechanisms underlying cue reactivity processes as well as to assess pharmacotherapies to suppress cue reactivity and therefore, modify relapse vulnerability. Advantages of the model include its translational relevance, and its face and predictive validities.&#160;The primary limitation of the model is that the cue reactivity task can only be performed infrequently and must only be used in short duration (e.g., 1 hour), otherwise rats will begin to extinguish the pairing of the discrete cues with the cocaine stimulus. The model is extendable to any positively reinforcing stimulus paired with discrete cues; though particularly applicable to drugs of abuse, this model may hold future applications in fields such as obesity, where palatable food rewards can act as positively reinforcing stimuli.

Cue reactivity is conceptualized as sensitivity to cues linked with drug-taking experiences that contribute to craving and relapse in abstinent humans. Cue reactivity is modeled in rats by measuring attentional orientation toward drug-associated cues that results in appetitive approach behavior in a cue reactivity test following self-administration and forced abstinence.

Cocaine use disorder (CUD) follows a trajectory of repetitive self-administration during which previously neutral stimuli gain incentive value. Cue ...

A Rat Model of Central Fatigue Using a Modified Multiple Platform Method

In this article, we introduced a rat model of central fatigue using the modified multiple platform method (MMPM). The Multiple Platform box was designed as a water tank with narrow platforms on the bottom. The model rats were put into the tank and stood on the platforms for 14 h (18:00 - 8:00) per day for a consecutive 21 days, with a blank control group set for contrast. At the end of modeling, rats in the model group showed an obvious fatigued appearance. To assess the model, we performed several behavioral tests, including the open field test (OFT), the elevated plus maze (EPM) test, and the exhaustive swimming (ES) test. The results showed that anxiety, spatial cognition impairment, poor muscle performance, and declined voluntary activity presented in model rats confirm the diagnosis of&#160;central fatigue. Changes of the central neurotransmitters also verified the result. In conclusion, the model successfully simulated central fatigue, and future study with the model may help reveal the pathological mechanism of the disease.

Here, we present a protocol to introduce a rat model of central fatigue using the modified multiple platform method (MMPM).

In this article, we introduced a rat model of central fatigue using the modified multiple platform method (MMPM). The Multiple Platform box was designed ...

A Novel and Translational Rat Model of Concussion Combining Force and Rotation with In Vivo Cerebral Microdialysis

Persistent cognitive and motor symptoms are known consequences of concussions/mild traumatic brain injury (mTBIs) that can be partly attributable to altered neurotransmission. Indeed, cerebral microdialysis studies in rodents have demonstrated an excessive extracellular glutamate release in the hippocampus within the first 10 min following trauma. Microdialysis offers the clear advantage of in vivo neurotransmitter continuous sampling while not having to sacrifice the animal. In addition to the aforementioned technique, a closed head injury model that exerts rapid acceleration and deceleration of the head and torso is needed, as such a factor is not available in many other animal models. The Wayne State weight-drop model mimics this essential component of human craniocerebral trauma, allowing the induction of an impact on the head of an unrestrained rodent with a falling weight. Our novel and translational rat model combines cerebral microdialysis with the Wayne State weight-drop model to study, in lightly anesthetized and unrestrained adult rats, the acute changes in extracellular neurotransmitter levels following concussion. In this protocol, the microdialysis probe was inserted inside the hippocampus as region of interest, and was left inserted in the brain at impact. There is a high density of terminals and receptors in the hippocampus, making it a relevant region to document altered neurotransmission following concussion. When applied to adult Sprague-Dawley rats, our combined model induced increases in hippocampal extracellular glutamate concentrations within the first 10 min, consistent with the previously reported post-concussion symptomology. This combined weight-drop model provides a reliable tool for researchers to study early therapeutic responses to concussions in addition to repetitive brain injury, since this protocol induces a closed-head mild trauma.

Neurotransmitter alteration is a mechanism of neural dysfunction that occurs after concussion and contributes to the sometimes-catastrophic long-term consequences. This rat model combines microdialysis, allowing in vivo neurotransmitter quantification, with a weight-drop technique exerting rapid acceleration and deceleration of the head and torso, an important factor of human craniocerebral trauma.

Persistent cognitive and motor symptoms are known consequences of concussions/mild traumatic brain injury (mTBIs) that can be partly attributable to ...

Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) is the most common type of acquired brain injury. Since patients with traumatic brain injury show a tremendous variability and heterogeneity (age, gender, type of trauma, other possible pathologies, etc.), animal models play a key role in unraveling factors that are limitations in clinical research. They provide a standardized and controlled setting to investigate the biological mechanisms of injury and repair following TBI. However, not all animal models mimic the diffuse and subtle nature of mTBI effectively. For example, the commonly used controlled cortical impact (CCI) and lateral fluid percussion injury (LFPI) models make use of a craniotomy to expose the brain and induce widespread focal trauma, which are not commonly seen in mTBI. Therefore, these experimental models are not valid to mimic mTBI. Thus, an appropriate model should be used to investigate mTBI. The Marmarou weight drop model for rats induces similar microstructural alterations and cognitive impairments as seen in patients who sustain mild trauma; therefore, this model was selected for this protocol. Conventional computed tomography and magnetic resonance imaging (MRI) scans commonly show no damage following a mild injury, because mTBI induces often only subtle and diffuse injuries. With diffusion weighted MRI, it is possible to investigate microstructural properties of brain tissue, which can provide more insight into the microscopic alterations following mild trauma. Therefore, the goal of this study is to obtain quantitative information of a selected region-of-interest (i.e., hippocampus) to follow up disease progression after obtaining a mild and diffuse brain injury.

The overall goal of this procedure is to obtain quantitative microstructural information of the hippocampus in a rat with mild traumatic brain injury. This is done using an advanced diffusion-weighted magnetic resonance imaging protocol and region-of-interest based analysis of parametric diffusion maps.

Mild traumatic brain injury (mTBI) is the most common type of acquired brain injury. Since patients with traumatic brain injury show a tremendous ...

A Rat Model of EcoHIV Brain Infection

It has been well studied that the EcoHIV infected mouse model is of significant utility in investigating HIV associated neurological complications. Establishment of the EcoHIV infected rat model for studies of drug abuse and neurocognitive disorders, would be beneficial in the study of neuroHIV and HIV-1 associated neurocognitive disorders (HAND). In the present study, we demonstrate the successful creation of a rat model of active HIV infection using chimeric HIV (EcoHIV). First, the lentiviral construct of EcoHIV was packaged in cultured 293 FT cells for 48 hours. Then, the conditional medium was concentrated and titered. Next, we performed bilateral stereotaxic injections of the EcoHIV-EGFP into F344/N rat brain tissue. One week after infection, EGFP fluorescence signals were detected in the infected brain tissue, indicating that EcoHIV successfully induces an active HIV infection in rats. In addition, immunostaining for the microglial cell marker, Iba1, was performed. The results indicated that microglia were the predominant cell type harboring EcoHIV. Furthermore, EcoHIV rats exhibited alterations in temporal processing, a potential underlying neurobehavioral mechanism of HAND as well as synaptic dysfunction eight weeks after infection. Collectively, the present study extends the EcoHIV model of HIV-1 infection to the rat offering a valuable biological system to study HIV-1 viral reservoirs in the brain as well as HAND and associated comorbidities such as drug abuse.

Here, we present a protocol to establish a new rat model of active HIV infection using chimeric HIV (EcoHIV), which is critical for enhancing our understanding of HIV-1 viral reservoirs in the brain and offering a system to study HIV-associated neurocognitive disorders and associated comorbidities (i.e., drug abuse).

It has been well studied that the EcoHIV infected mouse model is of significant utility in investigating HIV associated neurological complications. ...

Induction and Assessment of Levodopa-induced Dyskinesias in a Rat Model of Parkinson's Disease

Levodopa (L-DOPA) remains the gold-standard therapy used to treat Parkinson&#39;s disease (PD) motor symptoms. However, unwanted involuntary movements known as L-DOPA-induced dyskinesias (LIDs) develop with prolonged use of this dopamine precursor.&#160;It is estimated that the incidence of LIDs escalates to approximately 90% of individuals with PD within 10&#8211;15 years of treatment. Understanding the mechanisms of this malady and developing both novel and effective anti-dyskinesia treatments requires consistent and accurate modeling for pre-clinical testing of therapeutic interventions. A detailed method for reliable induction and comprehensive rating of LIDs following 6-OHDA-induced nigral lesioning in a rat model of PD is presented here. Dependable LID assessment in rats provides a powerful tool that can be readily utilized across laboratories to test emerging therapies focused on reducing or eliminating this common treatment-induced burden for individuals with PD.

Induction and Assessment of Levodopa-induced Dyskinesias in a Rat Model of Parkinson&#039;s Disease

This article describes methods to induce and evaluate levodopa-induced dyskinesias in a rat model of Parkinson&#39;s disease. The protocol offers detailed information regarding the intensity and frequency of a range of dyskinetic behaviors, both dystonic and hyperkinetic, providing a reliable tool to test treatments targeting this unmet medical need.

Levodopa (L-DOPA) remains the gold-standard therapy used to treat Parkinson&#39;s disease (PD) motor symptoms. However, unwanted involuntary movements ...

Electromagnetic Controlled Closed-Head Model of Mild Traumatic Brain Injury in Mice

Highly reproducible animal models of traumatic brain injury (TBI), with well-defined pathologies, are needed for testing therapeutic interventions and understanding the mechanisms of how a TBI alters brain function. The availability of multiple animal models of TBI is necessary to model the different aspects and severities of TBI seen in people. This manuscript describes the use of a midline closed head injury (CHI) to develop a mouse model of mild TBI. The model is considered mild because it does not produce structural brain lesions based on neuroimaging or gross neuronal loss. However, a single impact creates enough pathology that cognitive impairment is measurable at least 1 month after injury. A step-by-step protocol to induce a CHI in mice using a stereotaxically guided electromagnetic impactor is defined in the paper. The benefits of the mild midline CHI model include the reproducibility of the injury-induced changes with low mortality. The model has been temporally characterized up to 1 year after the injury for neuroimaging, neurochemical, neuropathological, and behavioral changes. The model is complementary to open skull models of controlled cortical impact using the same impactor device. Thus, labs can model both mild diffuse TBI and focal moderate-to-severe TBI with the same impactor.

The protocol describes mild traumatic brain injury in a mouse model. In particular, a step-by-step protocol to induce a mild midline closed head injury and the characterization of the animal model is fully explained.

Highly reproducible animal models of traumatic brain injury (TBI), with well-defined pathologies, are needed for testing therapeutic interventions and ...

Chinese Massage Techniques: Enhancing Motor Function in Cerebral Palsy Rats

Abdominal Massage to Improve Motor Dysfunction in Rats with Cerebral Palsy

Cerebral palsy (CP) is a disease with a high disability rate and morbidity. The clinical symptoms of cerebral palsy are motor dysfunction and abnormal posture development, often accompanied by cognitive impairment. Massage, a traditional Chinese Medicine therapy, can coordinate Zang and Fu, regulate Qi and blood, make the viscera work more smoothly, and calm Yin and Yang. Furthermore, it has been an effective method for CP in clinical. This paper summarizes a set of simple and standardized manipulations of massage for young rats with CP, which is easy to follow. The procedure follows: first, massage of four limb acupoints, including Quchi (LI11) and Zusanli (ST36); second, massage of the abdomen acupoints Zhongwan (RN12), Tianshu (ST25), Guanyuan (CV4), and Qihai (CV6); and finally, massage of the abdomen of the rats. This set of massage methods considerably improved the motor function of young rats with CP and is simple, standardized, and easy to follow. We adapted this set of manipulation methods in animal models to promote the internationalization and standardization of massage.

Author Spotlight: Exploring the Potential of Massage Therapy in Cerebral Palsy Using Animal Models 

Here, we present a set of massage manipulations in the rat model of cerebral palsy that can considerably improve the motor function of cerebral palsy rats.

Cerebral palsy (CP) is a disease with a high disability rate and morbidity. The clinical symptoms of cerebral palsy are motor dysfunction and abnormal ...

Validating Injury Response and Behavioral Assessments in an mTBI Rat Model

Rat Model of Closed-Head Mild Traumatic Injury and its Validation

Animal models are crucial for advancing our understanding of mild traumatic brain injury (mTBI) and guiding clinical research. To achieve meaningful insights, developing a stable and reproducible animal model is essential. In this study, we report a detailed description of a closed-head mTBI model and a representative validation method using Sprague-Dawley rats to verify the modeling effect. The model involves dropping a 550 g mass weight from a height of 100 cm directly onto the head of a rat on a destructible surface, followed by a 180-degree turn. To assess the injury, rats underwent a series of neurobehavioral assessments 10 min post-injury, including time of loss of consciousness, first seeking-behavior time, escape ability, and beam balance ability test. During the acute and subacute stages following the injury, behavioral tests were conducted to assess motor coordination ability (Beam task), anxiety (Open Field test), and learning and memory abilities (Morris Water Maze test). The closed-head mTBI model produced a consistent injury response with minimal mortality and replicated real-life situations. The validation method effectively verified the model development and ensured the stability and consistency of the model.

Author Spotlight: Advancing Traumatic Brain Injury Research - A Closed-Head Model for Accurate Replication and Rapid Assessment 

Here, we present a closed-head mild traumatic brain injury (mTBI) rat model and its validation exhibiting remarkable similarity to human mTBI concerning behavioral manifestations during the acute and subacute stages.

Animal models are crucial for advancing our understanding of mild traumatic brain injury (mTBI) and guiding clinical research. To achieve meaningful ...

Creating a Preterm Rat Model for Early Postnatal Pain Research

A Preterm Rat Model for Pain Studies

This research delves into the consequences of consistent pinprick stimulation on preterm offspring to ascertain its long-term implications for pain sensitivity. The primary objective of this protocol was to investigate the impact of neonatal pinprick stimuli on the pain threshold in the later stages of life using a preterm rat model. By establishing this model, we aim to advance the research on understanding and managing early postnatal pain associated with prematurity. The findings of this study indicate that while the baseline thresholds to mechanical stimuli remained unaffected, there was a notable increase in mechanical hypersensitivity following complete Freund's adjuvant (CFA) injection in adult rats. Interestingly, compared with male rats, female rats demonstrated heightened inflammatory hypersensitivity. Notably, maternal behavior, the weight of the litters, and the growth trajectory of the offspring remained unchanged by the stimulation. The manifestation of altered nociceptive responses in adulthood after neonatal painful stimuli could be indicative of changes in sensory processing and the functioning of glucocorticoid receptors. However, further research is needed to understand the underlying mechanisms involved and to develop interventions for the consequences of prematurity and neonatal pain in adults.

Here, we present a concise protocol for creating a preterm rat model, facilitating research on early postnatal pain management. The method involves performing a cesarean section three days before the expected birth, extracting preterm rat pups via hysterectomy, and integrating them with the biological offspring of a surrogate dam.

This research delves into the consequences of consistent pinprick stimulation on preterm offspring to ascertain its long-term implications for pain ...