| Objective:To establish the animal models of orthotopic fetal ovarian allotransplantation in rats, and explore the restoration of reproductive endocrine function in the models, furthermore, to provide an experimental animal models for the study on its natural fertility restoration and the health safety of its offsprings.Methods:90 female Sprague Dawley rats aged 50-60 days were divided randomly into 3 groups. One was Study Group (Graft Recipient Group) which enrolled 50 rats, the other was Normal Control Group (Positive Control Group) which enrolled 20 rats, and the third was Negative Control Group (Spayed Group) which enrolled 20 rats too. Fetal ovaries aged 17-19 gestational days were allotransplanted to the rats in Study Group orthotopically (bilateral oophorectomy were carried out in one setting in all rats from the Study Group), while "Open and Close Only" the abdominal wall were assigned to Normal Control Group (all rats in this group remained their normal ovaries unremoved), and bilateral oophorectomy were carried out in all rats in Spayed Group (no grafts were transplanted after the oophorectomy). From each of the three groups, 10 rats were selected randomly and serum estradiol and progesterone level of each rat were measured by electroluminescence test on day 45 after the transplantation, and at the same time the pelvic cavity were explored, bilateral ovaries were identified and removed completely for ovarian volume measurement and follicle development evaluation by ovarian histomorphology.Results:(1) On day 45 after the operations, the estradiol level (x±s) of Study Group, Normal Control Group and Negative Control Group were 114.65±15.59 pmol/L,121.71±14.92 pmol/L and 56.51±7.82 pmol/L, respectively; and progesterone level (x±s) were 12.79±4.40 ng/ml,13.00±1.18 ng/ml and 3.70±0.68 ng/ml, respectively. There is no statistical difference between Study Group and Normal Control Group regarding the estradiol level and progesterone level (P>0.05). However, regarding either the estradiol level or progesterone level between the Study Group and Spayed Group, there was statistical difference (P<0.05). (2) On day 45 after the operations, the ovarian volume of each ovary (x±s) were 0.22±0.07 ml,0.24±0.09 ml and 0 ml in Study Group, Normal Control Group and Spayed Group, respectively. There was no statistical difference between the Study Group and the Normal Control Group regarding the ovarian volume of each group (P>0.05). At light microscope, all stages of follicles development, including the mature follicles and corpus luteum were observed in ovaries of both Study Group and Normal Control Group.Conclusion:The fetal ovary can survive, grow and develop to a status possessing the function of ovulation, and can restore its reproductive endocrine function after being allotransplanted orthotopically in adult female rats.Objective:To investigate the restoration of natural fertility after orthotopic fetal ovarian allotransplantion in rats.Methods:40 female rats from the Study Group (fetal ovarian recipient group),10 from the Normal Control Group and 10 from the Spayed Group which were left in Part I study were selected in the present study. All the 60 female rats were feeded, respectively, with male rats aged from 45 to 65 days in the same cage (the ratio of female and male rats was 2:1) 45 days after the allotransplantation, the spayed operation or the "open and close" operation for 40 days. The pregnancy rate (once the female rate was pregnant, it would be seperated from the male rat during the obseration period) and the number of baby rats given by each birth was recorded and compared between each of the three groups (Study Group, Normal Control Group and the Spayed Group). After the 40-day observation period, the infertile female rats in the Study Group together with female rats in the Normal Control Group were investigated regarding the anatomic changes around the adnexa, and the follicle development status in both groups were detected to help figure out the causes to the infertility of the rats from the Study Group.Results:(1) The pregnancy rate of Study Group, Normal Control Group and the Spayed Group were 47.5%(19/40),100%(10/10),0.0% (0/10), respectively. Compared with the Normal Control Group, the pregancy rate in Study Group was significantly lower (P<0.05), while compared with Spayed Group, the pregnancy rate in Study Group was significantly higher (P<0.05). (2) The mean baby rats number (x±s) of each labor in the Study Group and Normal Control Group was 7.0±2.2 and 10.5±2.3, respectively. Compared to the Normal Control Group, the mean baby rats number of each labor in the Study Group was significantly lower (P<0.05). (3) Analysis of the causes to the infertility of the rats in the Study Group:according to the results of histomorphology, mature follicles developed and corpus luteum could be seen in the ovaries of the 21 infertile rats from the Study Group, which indicated that the allotransplanted fetal ovaries had survived and developed to a normal status. However, severe peri-adnexal adhesion was witnessed in the Study Group and no obvious peri-adnexal adhesion was observed in the Normal Control Group, which indicated that the severe pelvic adhesion might contribute to the infertility in the Study Group.Conclusion:Restoration of natural fertility might occur after orthotopic fetal ovarian allotransplantation in female rats; however, the pregancy rate, as well as the infant number of each labor was significantly lower compared to the Normal Control Group. It was possibly because of the severe pelvic adhesion postoperatively.Objective:To investigate preliminarily the health safety of the offspring delivered following naturally getting pregnant after the orthotopic fetal ovarian allotransplantation in rats. Methods:(1) Observation of any symptoms of sportaneous abortion during pregnancy period and of any possible still birth and death of infant rats within 3 days after the delivery was carried out in 19 pregnant rats from the previous Study Group and in 10 pregnant rats from the previous Normal Control Group from the Part II.The observed results were compared between the two groups. (2) 40 offspring rats each from the previous Study Group and Normal Control Group were selected randomly and marked as Study Group and Normal Control Group in the present study, respectively. The mean weight at day 35 after birth of both groups was measured and compared. (3) By means of routine G-banding technique, the karyotype analysis and the observation of chromosomal number and the structure were carried out. This might help understand preliminarily the health safety of offsprings delivered after the orthotopic fetal ovarian allotransplantation in rats.Results:(1) In both of the previous Study Group and Normal Control Group in Part II, neither sportaneous abortions nor still births and deaths of the infants within 3 days after the birth was observed. (2) Comparison of physical growth and development between the two offspring groups:The mean body weight (x±s) on age day 35 in the Study Group and Normal Control Group was 93.80±4.93g and 94.13±4.53g, respectively. There was no significant difference between the two groups regarding the mean body weight on day 35 after the birth of the offsprings (P>0.05). (3) The karyotype analysis indicated that the karyotype from the offspring delivered by both orthotopic fetal ovarian allotransplantation female recipients and the female rats in previously Normal Control Group in PartⅡwere 42, XX or 42, XY. No chromosome abnormality (abnormal chromosomal number or abnormal chromosomal structure) was observed in both groups.Conclusion:After the female recipient rat of orthotopic fetal ovarian allotransplantation getting pregnant, the spontaneous abortion rate, the still birth and death rate, as well as the chromosomal number and structure and the body weight of its offsprings were normal, which implied preliminarily that the health status of such an offspring was safe.
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