This work was supported by the Major Project Plan of the Special Development Fund for the Shanghai Zhangjiang National Independent Innovation Demonstration Zone (ZJ2022-ZD-006), Shanghai Municipal Science and Technology Commission Targeted Funding Project (22DX1900400), Youth Program of Shanghai Municipal Health Commission (20204Y0276). the National Natural Science Foundation of China (32070849).

The protocol of ICSI-ET described below follows the guidelines and has been approved by the Animal Ethical Review of the Shanghai Institute of Planned Parenthood research. Safety Procedures: Always wear appropriate personal protective equipment (PPE) when handling chemicals or biological materials. Use of Hoods: Perform all procedures involving volatile chemicals or aerosol generation within a certified fume hood or biosafety cabinet. Use female mice (6-8 weeks old B6D2F1 strain) for the superovulation procedure.
1. ICSI in mice
<ol>
	<li>Superovulation of mice
	<ol>
		<li>Administer an intraperitoneal injection of pregnant mare serum gonadotropin (PMSG) at a dose of 7.5 IU per mouse at around 20:00 on the first day.</li>
		<li>Administer an intraperitoneal injection of human chorionic gonadotropin (HCG) at a dose of 7.5 IU per mouse at around 20:00 (48 hours after PMSG injection) on the third day.</li>
	</ol>
	</li>
	<li>Prepare HTF medium into 1 mL aliquots and leave them uncovered for overnight equilibration at 37 &#176;C in a 5% CO2 incubator on the same day of HCG injection in female mice.</li>
	<li>Preparation of ICSI fertilization droplets
	<ol>
		<li>On the same day of HCG injection in female mice, divide a 50 x 9 mm cell culture dish lid into upper and lower halves. Use the upper half to create 4-6 droplets of 5 &#181;L each, using 10% polyvinylpyrrolidone (PVP) for sperm placement. Use the lower half to create 8-10 droplets of 5 &#181;L each, using M2 medium for the ICSI procedure.</li>
		<li>Cover the PVP and M2 medium droplets with approximately 3 mL of mineral oil (Figure 1).</li>
	</ol>
	</li>
	<li>Preparation of culture dishes
	<ol>
		<li>On the same day of HCG injection in female mice, dispense 12 drops of KSOM medium (MR-020P-D) of 20 &#181;L evenly in a 35 x 10 mm cell culture dish. Cover the drops with approximately 3 mL of mineral oil.</li>
	</ol>
	</li>
	<li>Sperm harvesting:
	<ol>
		<li>Euthanize male mice by cervical dislocation at approximately 9:00 am on the fourth day (13 h after HCG injection).</li>
		<li>Isolate the epididymal cauda and thoroughly clean it to eliminate any adipose tissue and blood remnants by gently blotting with sterile gauze and rinsing in prewarmed HTF medium.</li>
		<li>Cut open the cauda epididymis to allow the sperm to freely swim out into the HTF medium. Gently squeeze the cauda using forceps to release the sperm, collect them in preequilibrated HTF tubes, and keep them uncovered in a 37 &#176;C, 5% CO2 incubator for sperm capacitation for further use.</li>
	</ol>
	</li>
	<li>Oocyte retrieval
	<ol>
		<li>Euthanize female mice stimulated for oocyte retrieval by cervical dislocation at around 9:30 am on the fourth day. Carefully make an incision along the midline of the abdominal skin and muscle layer to expose the abdominal cavity.</li>
		<li>Use fine forceps to gently isolate tissue from both sides of the oviducts, especially the swollen ampulla regions, and transfer it into M2 medium in a sterilized culture dish. Repeat this procedure until the oviducts from all the designated mice are collected.</li>
		<li>Under a dissecting microscope, use a 1 mL syringe needle to puncture the transparent section of the swollen ampulla of the oviduct gently, facilitating the release of cumulus-oocyte complexes (COCs) into the medium.</li>
		<li>Using the same syringe, carefully pick and transfer the COCs into a new dish containing 100 &#181;L of fresh M2 medium. Repeat this step until all COCs are successfully transferred from the original oviduct segments.</li>
		<li>Wipe away blood and tissue fluids, and under a dissecting microscope, tear open the ampulla of the oviduct using a 25 G needle, resulting in the release of numerous COCs.</li>
		<li>Remove the oviduct and tissue fragments, transfer the COCs into droplets of M2 medium containing hyaluronidase (HY), and prewarm them to 37 &#176;C.</li>
		<li>After incubation for approximately 5 min, carry out gentle pipetting to facilitate the separation of cumulus cells and oocytes. Transfer the metaphase II (MII) oocytes from the HY-containing solution to fresh M2 medium; then, perform the sequential transfer into multiple droplets of M2 medium.</li>
		<li>After 2-3 rounds of washes, transfer the oocytes to droplets of KSOM culture medium and keep them in a 37 &#176;C, 5% CO2 incubator for further use.</li>
	</ol>
	</li>
	<li>Around 10:00 am on the fourth day, sonicate 100 &#181;L of the capacitated sperm (see step 1.5.2.) for 5 s to separate the heads from the tails at a frequency of 46 kHz, with a power setting of 50 watts. 
	NOTE: When sonicating sperm to truncate the tail, be cautious to control the time, which should not exceed 5 s. A few seconds after sonication, sperm can be observed under an inverted microscope; stop sonicating when approximately half of the sperm show truncated tails.</li>
	<li>ICSI procedure
	<ol>
		<li>Use a commercially available micromanipulation needle with a flat tip and an inner diameter of 6 &#181;m, set at a 25&#176; angle, for the injection. Fill the needle with the operating fluid with the filled portion measuring a length of 0.5 cm inside the needle. Ensure that the level of the fluid reaches ~0.5 cm. 
		NOTE: Maintain room temperature at 19 &#176;C during injection to avoid high temperatures that may reduce the survival rate of fertilized oocytes. The precision in ensuring the fluid level reaches 0.5 cm is crucial for maintaining the integrity of the injection process and ensuring the viability of the oocytes.</li>
		<li>Install the injection needle on the right arm of the micromanipulator, securely fixed by tightening the holding cap. Install a commercially available flat-tipped micromanipulation holding pipette designed for mouse oocytes on the left arm of the micromanipulator, and position the injection needle and the holding pipette in the microscope&#39;s field of view.</li>
		<li>Add 1 &#181;L of sonicated sperm to a droplet of PVP solution using a pipette.</li>
		<li>Place 20 MII oocytes in a droplet of M2 medium.</li>
		<li>Use the injection needle to aspirate 10-20 sperm heads in PVP solution. Then, move the injection needle into the droplet containing the oocytes.</li>
		<li>Directly determine the position of the metaphase spindle within the oocyte under a polarization microscope to ensure that the spindle apparatus is not on the side of injection, with the polar body typically located at either the 12 o&#39;clock or 6 o&#39;clock position relative to the oocyte&#39;s orientation.</li>
		<li>Keep the oocyte in contact with the bottom of the culture dish. Adjust the focal plane so that the zona pellucida of the oocyte and the injection needle are in the same plane.</li>
		<li>Upon contact of the injection needle with the zona pellucida, apply a slight negative pressure to the injection needle, drawing in a portion of the zona pellucida.</li>
		<li>Simultaneously activate piezo pulses with an intensity setting of 5 and a frequency of 1, effectively creating a perforation in the zona pellucida and allowing the injection needle to pass through.</li>
		<li>Advance the injection needle into the perivitelline space, pushing the sperm head to the tip of the needle. Insert the injection needle into the oocyte until it reaches the opposite side of the zona pellucida.</li>
		<li>Use piezo pulses set to an intensity of 1 and a frequency of 1 to create a small pore in the plasma membrane, ensuring the sperm head is injected into the ooplasm with minimal entry of PVP and optimal preservation of the oocyte&#39;s integrity.</li>
		<li>Repeat step 1.8.11 until all 20 oocytes are injected, followed by a 15 min incubation at 19 &#176;C.</li>
		<li>Transfer the surviving oocytes to KSOM medium and place them in the incubator. Observe 2-cell, 4-cell, morula, and blastocyst formation rates. 
		NOTE: Timing for intracytoplasmic single sperm injection (ICSI) into the oocyte should be controlled, aiming to complete the procedure within 14-18 h after the injection of HCG.</li>
	</ol>
	</li>
</ol>
2. Uterine transplantation of mouse blastocysts
<ol>
	<li>Preparation of vasectomized male mice 
	NOTE: Use ICR male mice aged 6-8 weeks for the study.
	<ol>
		<li>Induce anesthesia by intraperitoneal injection of 1.25% 2,2,2-tribromoethanol at a dosage of 0.2 mL/10 g of body weight. The absence of any pain response indicates successful anesthetization. 
		NOTE: While the current protocol does not include the application of vet ointment to the eyes of anesthetized animals, it is recommended as a best practice to prevent eye dryness and ensure the health and comfort of the animals during procedures. Throughout the surgical and recovery process, all surgical instruments were sterilized before use, and the surgical area was prepared using antiseptic solutions to ensure a clean operating environment.</li>
		<li>To safeguard against potential stress or injury, house the mice that have undergone surgery individually during the initial recovery phase.</li>
		<li>Administer buprenorphine at a dosage of 0.05 mg/kg of body weight to ensure optimal pain relief. 
		NOTE: To ensure the well-being of the mice, closely monitor the mice during the recovery period and do not leave them unattended until they regain sufficient consciousness to maintain sternal recumbency.</li>
		<li>Prepare the surgical site at the lower abdominal region, superior to the testes. Remove the fur and disinfect with povidone-iodine. Using sterile scissors, make a 1 cm longitudinal incision along the linea alba. Gently remove any blood with sterile, dust-free paper and proceed to bluntly dissect the abdominal muscles along the linea alba and access the abdominal cavity.</li>
		<li>Using curved forceps, gently grasp and expose the left testis and its associated fat pad. Identify the vas deferens and carefully isolate it using pointed forceps, creating a 10 mm segment for manipulation.</li>
		<li>Sterilize the curved forceps by holding them in the outer flame of an alcohol lamp for several seconds. Gently grasp the vas deferens, causing it to become flattened and whitened due to cauterization. Create a second cauterization point 3-5 mm distal to the first. Using sterile surgical scissors, excise the segment of the vas deferens between the two cauterization points.</li>
		<li>Carefully inspect the cauterized ends of the vas deferens, ensuring that a short, flattened, whitened segment remains. Using curved forceps, gently return the testis and its associated fat pad to the abdominal cavity.</li>
		<li>Repeat the procedure described in step 2.1.6 on the contralateral (right) side.</li>
		<li>Close the surgical site using sutures, typically placing one stitch in the muscle layer and three stitches in the skin. Ensure proper alignment of the surgical incision and disinfect with povidone-iodine. Transfer the animal to a heating pad for observation, monitoring for 10-15 min until the animal regains consciousness. Once recovered, return the animal to its housing cage. 
		NOTE: Following vasectomy surgery, mice require a 14-day recovery period, followed by a 1-week trial mating experiment.</li>
		<li>During this week, continuously mate the vasectomized males with females and observe the pregnancy status of all females presenting with copulatory plugs. Successful mating is indicated by the presence of a yellowish-white, blocky vaginal plug at the vaginal orifice of the female mouse.
		<ol>
			<li>Pair the mice between 4:00 PM and 6:00 PM on the first day and check the vaginal plugs between 7:00 AM and 9:00 AM on the second day. Consider females with vaginal plugs to be in a pseudopregnant state at 0.5 days and use them for subsequent embryo transfer experiments. Return females without vaginal plugs to the recipient group. 
			NOTE: These females without vaginal plugs can continue to be used for mating to prepare pseudopregnant females. Ensure that all plugged females do not become pregnant; only then can the vasectomized males be used for formal experiments.</li>
			<li>While vasectomized males can mate daily, allow for 1 day of rest between mating sessions. 
			NOTE: Based on our experience, vasectomized males can maintain a high copulatory plug rate for over a year. However, vasectomized males that fail to produce copulatory plugs in mating females for 4-6 consecutive attempts should be removed from the study.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Preparation of pseudopregnant females
	<ol>
		<li>Generate pseudopregnant female mice by mating ICR female mice (aged 7-10 weeks, weighing over 25 g) with vasectomized male mice (3-6 months old) at a 1:1 ratio. 
		NOTE: The vasectomized males were used to stimulate the uterine cervix of the female mice, resulting in the activation of the corpora lutea.</li>
	</ol>
	</li>
	<li>Preparation of the pipette for transferring blastocysts
	<ol>
		<li>Take the embryos to be transplanted out from the incubator and transfer them into a droplet of M2 medium at a temperature of 37 &#176;C.</li>
		<li>Use a transfer pipette to aspirate a small volume of liquid, draw a small amount of air, and aspirate 6-10 embryos. Finally, aspirate another small volume of air to seal the pipette. 
		NOTE: The length of the fluid in the transfer pipette should not exceed 0.5 cm.</li>
	</ol>
	</li>
	<li>Uterine transplantation (blastocysts)
	<ol>
		<li>Weigh the pseudopregnant female mice (2.5 days post mating) and anesthetize them by intraperitoneal injection of 1.25% 2,2,2-tribromoethanol at a dose of 0.2 mL/10 g of body weight. Gently press the ear with forceps.</li>
		<li>After administering anesthesia to the mice and ensuring asepsis through alcohol disinfection, make a midline longitudinal incision on the ventral abdomen. Taking advantage of the loose subcutaneous tissue, shift the incision to the left or right side as required for the transplant. Use small scissors to perform blunt dissection of the abdominal wall muscle layer at ~0.5 cm lateral to the lumbar spine to access the peritoneal cavity.</li>
		<li>Using atraumatic forceps, carefully exteriorize the ovaries, oviducts, and uterus.</li>
		<li>Using the tip of a syringe needle, make a small, upward-angled incision on the uterine wall below the utero-tubal junction, avoiding blood vessels. This incision provides access to the uterine cavity; gently insert the oviduct 2-3 mm through the small hole.</li>
		<li>Carefully expel the small air bubble at the end of the transfer pipette while cautiously watching the transfer pipette during the slow injection of the embryos. Once the central portion of the culture medium is confirmed to be expelled, halt the procedure and gently remove the transfer pipette.</li>
		<li>Reposition the ovaries, oviducts, and uterus back into the abdominal cavity. Suture the muscle layer and skin separately. Place the mice on a heating pad until they recover from anesthesia. To ensure the well-being of the mice, closely monitor the mice during the recovery period and do not leave them unattended until they regain sufficient consciousness to maintain sternal recumbency.</li>
	</ol>
	</li>
	<li>Observation of pregnancy
	<ol>
		<li>Following the surgery, observe the mice for 18-21 days to monitor the number of offspring born. In case of dystocia (difficult birth), perform a cesarean section. Allow the newborn mice to be fostered by lactating dams of the same age group.</li>
	</ol>
	</li>
</ol>
3. Random blood glucose, fasting blood glucose, and glucose tolerance test
<ol>
	<li>Tracking random blood glucose levels during mouse growth
	<ol>
		<li>Since the birth of the mice, monitor the random blood glucose level every 4 weeks at 9 am after a good night of feeding and fun.
		<ol>
			<li>Puncture the mouse tail tip to obtain tail vein blood.</li>
			<li>The first drop of blood has a higher sugar measurement value due to the presence of the tissue fluid mixed with it. Therefore, wipe the first drop of blood using clean absorbent paper gently.</li>
			<li>Measure the blood glucose from the second drop (~4 &#181;L) from the tail vein with a handheld glucometer.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Tracking changes in fasting blood glucose and glucose tolerance during mice development 
	NOTE: Considering that the first blood sampling time point is 15 min, all mice need to be injected within 15 min. Since each mouse injection took 20-30 s, to ensure that the injections are completed within this timeframe, the maximum number of mice that can be used in each test cannot exceed 30.
	<ol>
		<li>Perform the fasting blood glucose and glucose tolerance tests every 4 weeks after birth in overnight-fasted mice.
		<ol>
			<li>On the first day, prepare fresh irradiated shavings bedding, clean cages, lids, and water bottles. Transfer the mice into a fresh cage without food. Add do not feed tags to the cages.</li>
			<li>Prepare sufficient 10% glucose injection (sterile and pyrogen-free) and 1 mL syringes.</li>
			<li>Ensure that the mice in each group fast for 16 h, from 5:00 pm on day 1 to 9:00 am on day 2, but allow free access to water. Measure the fasting blood glucose levels as described in steps 3.1.1.1-3.1.1.3 using a glucose meter.</li>
		</ol>
		</li>
		<li>Weigh the mice and mark their tails to facilitate rapid identification. Prepare glucose syringes with 10 &#181;L/g of mouse weight.</li>
		<li>At 30 s intervals, inject 10 &#181;L/g glucose into the intraperitoneal cavity of the mouse. 
		NOTE: Special attention needs to be paid to injection techniques here to avoid inaccurate liquid injection volume. The key points of operation are as follows:
		<ol>
			<li>Immobilize the mouse and restrain the tail with one hand. Keep the head slightly lower than the buttocks so that the organs in the abdominal cavity will shift towards the head, leaving enough injection space.</li>
			<li>Position the needle between the midline and the hip bone, insert it through the skin at a 45-degree angle, then gently guide the needle deeper into the abdominal cavity while keeping it aligned parallel to the skin surface for ~0.5 cm. 
			NOTE: Pay attention to any resistance during injection to determine whether the internal organs are accidentally punctured.</li>
			<li>Eject the syringe into the abdominal cavity.</li>
			<li>Record the time when the injection started and use a timer to control the injection rate. Set the timer to 90 s for three mice to avoid losing time in handling the timer.</li>
		</ol>
		</li>
		<li>Take the blood glucose measurement from the tail vein at the desired intervals (0 prior to glucose administration, 15, 30, 60, 90, and 120 min after the glucose loading). 
		NOTE: Subsequent blood glucose testing should also take 20-30 s for each mouse.</li>
		<li>Return the mice to their home cages equipped with food and water after the experiment.</li>
	</ol>
	</li>
</ol>

ICSI-ET Mouse Model to Study Long-Term Impacts on Glucose Metabolism

<ol>
	<li>Palermo, G., Joris, H., Devroey, P., Van Steirteghem, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pregnancies+after+intracytoplasmic+injection+of+single+spermatozoon+into+an+oocyte.">Pregnancies after intracytoplasmic injection of single spermatozoon into an oocyte.</a> Lancet. 340 (8810), 17-18 (1992).</li><li>Flurkey, K. M., Currer, J., Harrison, D. E., Fox, J. G., 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=Vol.+III+Mouse+models+in+aging+research.+Ch.+20.">Vol. III Mouse models in aging research. Ch. 20.</a> The mouse in biomedical research (second edition). , 637-672 (2007).</li><li>Chen, M., Heilbronn, L. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+health+outcomes+of+human+offspring+conceived+by+assisted+reproductive+technologies+(art).">The health outcomes of human offspring conceived by assisted reproductive technologies (art).</a> J Dev Orig Health Dis. 8 (4), 388-402 (2017).</li><li>Heber, M. F., Ptak, G. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effects+of+assisted+reproduction+technologies+on+metabolic+health+and+diseasedagger.">The effects of assisted reproduction technologies on metabolic health and diseasedagger.</a> Biol Reprod. 104 (4), 734-744 (2021).</li><li>Ma, R. C. W., Ng, N. Y. H., Cheung, L. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assisted+reproduction+technology+and+long-term+cardiometabolic+health+in+the+offspring.">Assisted reproduction technology and long-term cardiometabolic health in the offspring.</a> PLoS Med. 18 (9), e1003724 (2021).</li><li>De Waal, 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=The+cumulative+effect+of+assisted+reproduction+procedures+on+placental+development+and+epigenetic+perturbations+in+a+mouse+model.">The cumulative effect of assisted reproduction procedures on placental development and epigenetic perturbations in a mouse model.</a> Hum Mol Genet. 24 (24), 6975-6985 (2015).</li><li>Carlin, J., George, R., Reyes, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methyl+donor+supplementation+blocks+the+adverse+effects+of+maternal+high+fat+diet+on+offspring+physiology.">Methyl donor supplementation blocks the adverse effects of maternal high fat diet on offspring physiology.</a> PLoS One. 8 (5), e63549 (2013).</li><li>Hiraoka, 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=Piezo-icsi+for+human+oocytes.">Piezo-icsi for human oocytes.</a> J Vis Exp. (170), e60224 (2021).</li><li>Sullivan-Pyke, C. S., Senapati, S., Mainigi, M. A., Barnhart, K. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+fertilization+and+adverse+obstetric+and+perinatal+outcomes.">In vitro fertilization and adverse obstetric and perinatal outcomes.</a> Semin Perinatol. 41 (6), 345-353 (2017).</li><li>Luke, B., 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+risk+of+birth+defects+with+conception+by+art.">The risk of birth defects with conception by art.</a> Hum Reprod. 36 (1), 116-129 (2021).</li><li>Norrman, 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=Cardiovascular+disease,+obesity,+and+type+2+diabetes+in+children+born+after+assisted+reproductive+technology:+A+population-based+cohort+study.">Cardiovascular disease, obesity, and type 2 diabetes in children born after assisted reproductive technology: A population-based cohort study.</a> PLoS Med. 18 (9), e1003723 (2021).</li><li>Goldsmith, S., Mcintyre, S., Badawi, N., Hansen, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cerebral+palsy+after+assisted+reproductive+technology:+A+cohort+study.">Cerebral palsy after assisted reproductive technology: A cohort study.</a> Dev Med Child Neurol. 60 (1), 73-80 (2018).</li><li>Hansen, 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=Intellectual+disability+in+children+conceived+using+assisted+reproductive+technology.">Intellectual disability in children conceived using assisted reproductive technology.</a> Pediatrics. 142 (6), e20181269 (2018).</li><li>Chang, R. C., Wang, H., Bedi, Y., Golding, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preconception+paternal+alcohol+exposure+exerts+sex-specific+effects+on+offspring+growth+and+long-term+metabolic+programming.">Preconception paternal alcohol exposure exerts sex-specific effects on offspring growth and long-term metabolic programming.</a> Epigenetics Chromatin. 12 (1), 9 (2019).</li><li>Grasemann, C., 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=Parental+diabetes:+The+akita+mouse+as+a+model+of+the+effects+of+maternal+and+paternal+hyperglycemia+in+wildtype+offspring.">Parental diabetes: The akita mouse as a model of the effects of maternal and paternal hyperglycemia in wildtype offspring.</a> PLoS One. 7 (11), e50210 (2012).</li></ol>

The authors have no conflicts of interest to disclose.

This study integrated mouse intracytoplasmic sperm injection (ICSI) and embryo transfer (ET) techniques to comprehensively recapitulate human assisted reproductive technology (ART) and examine the impact of ICSI in conjunction with ET on offspring development. The application of the ICSI technique with normal mouse sperm yielded high fertilization (86.76%) and 2-cell rates (88.48%). Following ET, the birth rate of offspring mice was approximately 42.50%, indicating the robustness of the technical platform. The most notew...

Fertility issues have emerged as a major focus of medical and sociological concern, especially in modern society where declining fertility rates and the increasing severity of infertility prevalence and severity have risen to prominence. Assisted Reproductive Technology (ART) provides a wide array of possibilities to tackle these challenges, with Intracytoplasmic Sperm Injection (ICSI) commonly utilized as a therapeutic intervention.
Since Palermo reported the first successful pregnancy achieved through Intracytoplasmic Sperm Injection (ICSI) in 1992, ICSI has become a pivotal technique in Assisted Reproductive Technologies (ART)1. However, considering that ICSI has been used in clinical settings for only 30 years, a relatively brief period compared to the human lifespan, the long-term effects of ICSI, especially on offspring development, have not been extensively investigated and elucidated. At present, mice characterized by their uniform genetic background and shorter lifespan, have emerged as a widely utilized alternative model in medical research. Moreover, the mouse model can recapitulate the entire human lifespan within a compressed time frame, where one year in mice roughly corresponds to 40 years in humans2.
Over the past decade, several small-scale studies have reported that individuals conceived through ICSI may be at an increased risk of developing metabolic syndromes, such as abnormal blood sugar levels, later in life3,4. Although the evidence is not definitive, this finding has nonetheless raised serious concerns within the scientific community regarding the long-term health implications of ICSI. This situation underscores the pressing need for more rigorous assessments of ART and its long-term health consequences. Particularly in light of the limitations and ethical considerations of human studies, developing animal models that can precisely recapitulate the development of human offspring following ICSI has become increasingly crucial. In this context, the mouse ICSI-ET (Intracytoplasmic Sperm Injection-Embryo Transfer) model, owing to its capacity to mimic the human ICSI and facilitate long-term monitoring of offspring health outcomes, has become an effective tool for assessing the potential health risks of ICSI technology to offspring5.
This study aims to investigate the impact of ICSI-ET technology on a prevalent metabolic phenotype, namely offspring glucose metabolic health, by employing random blood glucose monitoring, fasting blood glucose testing, and glucose tolerance tests to assess the glucose metabolic state of mice. Random blood glucose monitoring is utilized to capture the natural fluctuations in glucose metabolism during normal physiological activities, whereas fasting blood glucose and glucose tolerance tests are employed to assess potential prediabetic states.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1.25% avertin (2,2,2-tribromoethanol)</td>
			<td>Nanjing Aibei</td>
			<td>M2960</td>
			<td>for anesthetization</td>
		</tr>
		<tr>
			<td>Bacteriological Petri Dishes 35 x 10 mm style w/tight lid, crystal-grade virgin polystyrene, sterile</td>
			<td>BD</td>
			<td>353001</td>
			<td></td>
		</tr>
		<tr>
			<td>Bacteriological Petri Dishes 50 x 9 mm style w/tight lid, crystal-grade virgin polystyrene, sterile</td>
			<td>BD</td>
			<td>351006</td>
			<td></td>
		</tr>
		<tr>
			<td>Biosafety Cabinet</td>
			<td>ESCO</td>
			<td>class <img alt="Equation 1" src="/files/ftp_upload/66212/66212eq01.jpg" style="margin: auto;" /> BSC</td>
			<td>Aseptic operations, making culture dishes, aliquoting reagents, etc.</td>
		</tr>
		<tr>
			<td>CO2 Incubator</td>
			<td>Thermo</td>
			<td>8000DH</td>
			<td>Embryo culture</td>
		</tr>
		<tr>
			<td>Dissection Microscope</td>
			<td>Olympus</td>
			<td>SZX16</td>
			<td>Use in mouse embryo transfer</td>
		</tr>
		<tr>
			<td>Fluorinert Fc-770</td>
			<td>SIGMA</td>
			<td>F3556</td>
			<td>Fluorinert FC-770 is a thermally stable fully fluorinated liquid with high dielectric strength and resistivity, used as operating fluid</td>
		</tr>
		<tr>
			<td>handheld glucometer</td>
			<td>Roche</td>
			<td>AccuChek performa</td>
			<td>Blood glucose measurement</td>
		</tr>
		<tr>
			<td>HTF</td>
			<td>Merck</td>
			<td>MR-070-D</td>
			<td>The EmbryoMax Human Tubal Fluid (HTF) (1x), liquid designed for use with Mouse IVF is available in a 50 mL format and has been optimized and validated for Embryo Culture.</td>
		</tr>
		<tr>
			<td>Hydraulic Microinjector</td>
			<td>Eppendorf</td>
			<td>CellTram 4r Oil, 5196000030</td>
			<td>For sperm injection</td>
		</tr>
		<tr>
			<td>Inverted Microscope</td>
			<td>Nikon</td>
			<td>TI2-U</td>
			<td>Micromanipulation observation host</td>
		</tr>
		<tr>
			<td>KSOM</td>
			<td>Merck</td>
			<td>MR-020P-D</td>
			<td>(1x), Powder, w/o Phenol Red, 5 x 10 mL</td>
		</tr>
		<tr>
			<td>M2</td>
			<td>Merck</td>
			<td>MR-015-D</td>
			<td>EmbryoMax M2 Medium (1x), Liquid, with Phenol Red</td>
		</tr>
		<tr>
			<td>Micromanipulator</td>
			<td>NARISHIGE</td>
			<td>NTX-N4</td>
			<td>Micromanipulation arm</td>
		</tr>
		<tr>
			<td>mineral oil&#160;</td>
			<td>SIGMA</td>
			<td>M8410</td>
			<td>Mineral oil is suitable for use as a cover layer to control evaporation and cross-contamination in various molecular biology applications.</td>
		</tr>
		<tr>
			<td>Needle Cutter</td>
			<td>Nanjing Aibei</td>
			<td>Sutter MF-800</td>
			<td>Use for fabricating micromanipulation needles</td>
		</tr>
		<tr>
			<td>Needle Puller</td>
			<td>Nanjing Aibei</td>
			<td>Sutter model p-100</td>
			<td>Use for making micromanipulation needles</td>
		</tr>
		<tr>
			<td>Piezo Drill Trip Mouce ICSI</td>
			<td>Eppendorf</td>
			<td>5195000.087</td>
			<td>Application of ICSI injection needle.</td>
		</tr>
		<tr>
			<td>Piezoelectric Micromanipulator (Membrane Breaker)</td>
			<td>Eppendorf</td>
			<td>Eppendorf PiezoXpert</td>
			<td>Use of micro-pulses to break the zona pellucida and oolemma of the oocyte</td>
		</tr>
		<tr>
			<td>Pneumatic Microinjector</td>
			<td>Eppendorf</td>
			<td>CellTram 4r Air, 5196000013</td>
			<td>For fixing the oocyte</td>
		</tr>
		<tr>
			<td>Ready-to-use Human Chorionic Gonadotropin (Hcg)</td>
			<td>Nanjing Aibei</td>
			<td>M2520</td>
			<td>Sterilization reagent, intraperitoneal injection. 50 IU/mL</td>
		</tr>
		<tr>
			<td>Ready-to-use Pregnant Mare&#39;s Serum Gonadotropin (PMSG)</td>
			<td>Nanjing Aibei</td>
			<td>M2620</td>
			<td>Sterilization reagent, intraperitoneal injection. 50 IU/mL</td>
		</tr>
		<tr>
			<td>Stereomicroscope</td>
			<td>Olympus</td>
			<td>SZX7</td>
			<td>Oocyte retrieval and observation of embryo development</td>
		</tr>
	</tbody>
</table>

monitoring blood glucose in mouse offspring after intracytoplasmic sperm injection

Human lifespan is considerably long, while mouse models can simulate the entire human lifespan in a relatively short period, with one year of mouse life roughly equivalent to 40 human years. Intracytoplasmic sperm injection (ICSI) is a commonly used assisted reproductive technology in clinical practice. However, given its relatively recent emergence about 30 years ago, the long-term effects of this technique on human development remain unclear. In this study, we established the ICSI combined with embryo transfer (ET) method using a mouse model. The results demonstrated that normal mouse sperm, after undergoing in vitro culture and subsequent ICSI, exhibited a fertilization rate of 89.57% and a two-cell rate of 87.38%. Following ET, the birth rate of offspring was approximately 42.50%. Furthermore, as the mice aged, fluctuations in glucose metabolism levels were observed, which may be associated with the application of the ICSI technique. These findings signify that the mouse ICSI-ET technique provides a valuable platform for evaluating the impact of sperm abnormalities on embryo development and their long-term effects on offspring health, particularly concerning glucose metabolism. This study provides important insights for further research on the potential effects of the ICSI technique on human development, emphasizing the necessity for in-depth investigation into the long-term implications of this technology.

Author Spotlight: Exploring the Long-Term Health Impacts of Intracytoplasmic Sperm Injection on Offspring

Monitoring Blood Glucose in Mouse Offspring After Intracytoplasmic Sperm Injection

We're looking into whether the techniques used in ICSI might cause metabolic disorder in offspring. It's really important because it ensures the safety and development of assisted reproductive technology. Our research provide a solid foundation for future study enabling researchers to explore how sperm impact on embryo growth and the offspring health over time.Our team will focus on cardiovascular health and the immune system outcomes in ICSI offspring aiming to provide a comprehensive understanding of their long-term health.

In our laboratory, we have achieved a fertilization rate of 89.57% and a 2-cell rate of 87.38% using ICSI with epididymal caudal sperm in mice. The birth rate of offspring following ET is approximately 42.50%. Remarkably, all the fertilization rates, 2-cell rates, and offspring birth rates are comparable to the levels achieved in human ART, enabling a comprehensive simulation of different stages of human ART techniques in mice. Further details are provided in Table 1 and Table 2. There w...

Read this Scientific Article Protocol about Monitoring Blood Glucose in Mouse Offspring after Intracytoplasmic sperm injection - Embryo Transfer at JoVE.com

Here, we present a protocol to establish an intracytoplasmic sperm injection (ICSI)-embryo transfer (ET) mouse model, allowing us to observe age-related changes in glucose metabolism that may be attributed to ICSI, providing insights into its potential long-term impacts on human development.

Human lifespan is considerably long, while mouse models can simulate the entire human lifespan in a relatively short period, with one year of mouse life ...

monitoring-blood-glucose-mouse-offspring-after-intracytoplasmic-sperm

Research

JoVE Journal

Developmental Biology

Intracytoplasmic Sperm Injection (ICSI) and Metabolic Assessments in Mice 

To begin, place the experimental female mouse on a working platform. Intraperitoneally, administer 7.5 international units of pregnant mare serum gonadotropin around 8:00 PM on the first day. After 48 hours, intraperitoneally inject 7.5 international units of human chorionic gonadotropin.Divide a cell culture dish lid into upper and lower halves. In the upper half, place four to six droplets of five microliter each of PVP for sperm placement. Add 8 to 10 droplets of five microliter each of M2 medium in the lower half for the ICSI procedure.Cover the PVP and M2 medium droplets with approximately three milliliters of mineral oil. After isolating epididymal cauda from the euthanized male mouse, gently blot it on sterilized gauze. Cut open the cauda epididymis and gently squeeze, using forceps to release the sperm, collecting them in pre-equilibrated human tubal fluid tubes.Rinse the cauda epididymis in the pre-warmed human tubal fluid medium. Place the tube uncovered at 37 degrees Celsius and 5%carbon dioxide incubator for sperm capacitation. On the fourth day after injecting human chorionic gonadotropin, place the euthanized female mouse under a dissecting microscope.Using a 25-gauge needle, tear open the ampulla of the oviduct to release numerous cumulus oocyte complexes. After capacitation, sonicate 100 microliters of the sperm for five seconds to separate the heads from the tails. Fill the micromanipulation needle with the operating fluid, ensuring the filled portion measures 0.5 centimeters inside the needle.Install the needle on the right arm of the micromanipulator and secure it by tightening the holding cap. Then install a flat-tipped micromanipulation holding pipette on the left arm of the micromanipulator. Position the injection needle and the holding pipette in the microscope's field of view.Under a polarization microscope, determine the position of the metaphase spindle within the oocyte to ensure that the spindle apparatus is not on the injection side. Upon contact of the injection needle with the zona pellucida, activate Piezo pulses with an intensity of five and frequency of one, creating a perforation in the zona pellucida and allowing the injection needle to pass through. Using Piezo pulses of intensity one and frequency one, create a small pore in the plasma membrane, ensuring the sperm head is injected into the ooplasm.Using atraumatic forceps, carefully exteriorize the ovaries, oviducts, and uterus from the anesthetized pseudo-pregnant female mouse. Make a small upward-angled incision using the tip of a syringe needle on the uterine wall below the uterotubal junction, avoiding blood vessels. Gently insert the oviduct two to three millimeters through the small hole.Using the ICSI method, a fertilization rate of 89.57%was achieved in mice, with 87.38%of zygotes advancing to the 2-cell embryo stage within 24 hours post ICSI. The birth rate of live pups post embryo transfer was observed at 42.5%There was no significant fluctuation in random blood glucose levels between mice born naturally and ICSI mice. However, male ICSI mice consistently exhibited elevated fasting blood glucose levels, suggesting impaired glucose homeostasis.In glucose tolerance tests, significant differences in blood glucose levels were noted between male ICSI and control mice, while no difference was observed in female mice. In body weight tracking, both male and female ICSI mice exhibited an overweight phenotype compared to controls.

323 Views.  Shanghai-MOST Key Laboratory of Health and Disease Genomics.  Here, we present a protocol to establish an intracytoplasmic sperm injection (ICSI)-embryo transfer (ET) mouse model, allowing us to observe age-related changes in glucose metabolism that may be attributed to ICSI, providing insights into its potential long-term impacts on human development.

ICSI-ET Mouse Model to Study Long-Term Impacts on Glucose Metabolism

Summary