| ObjectiveWe developed a model of chronic endometrial ischemia in the rat induced to detect the expression of telomerase, POU5f1, c-kit and caspase3 by bilateral uterine artery ligation.MethodsSix-month-old virgin female Sprague–Dawley rats were from Chongqing Medical University and maintained in collective cages in an appropriate room with controlled temperature and with a 12-h light cycle and fed with standard rat chow and water. All animals were acclimatized for three days before the experiment started. The experimental group rats were anesthetized with intraperitoneal xylazine (8 mg/kg) and ketamine (40 mg/kg), and both uterine arteries were ligated. Control group rats underwent the identical anesthetic and surgical procedure and neither uterine artery was ligated. Vaginal smears were taken to determine estrous cycle phase. Two months after the operation, the animals were killed under isoflurane anesthesia on the day of estrus. Then, random samples of uterus were frozen in liquid nitrogen. All samples were stored at -70℃. To observe the endometrial thickness, luminal epithelium thickness, gland epithelium thickness and the number of glands in experiment group and the control group using a light microscope. TERT and caspase3 were detected by Immunohistochemistry. Pou5f1, c-kit and caspase3 mRNA expression in endometrial tissue of experimental and control were examined by qPCR. C-kit, caspase3 and telomerase were detected by western blot.Results1. Histological findings suggest that the endometrial thickness(502±148), luminal epithelium thickness(17.20±4.98), gland epithelium thickness(9.17±1.96)and the number of glands(18.9±4.8)in experiment group rats were significantly decreased compared to that [(800±130),(29.46±9.27),(15.68±2.50),(30±5.5)] in control group (P<0.05).2. Immunohistochemistry showed that the expression level of caspase3 and telomerase were significantly lower in experimental group than that in control group(P<0.05). The expression of c-kit mRNA and protein in experimental group was significant lower than that in control group(0.235±0.012 and 0.31±0.13 vs 1±0.063 and 0.75±0.09, P<0.05). The expression of caspase3 mRNA and protein in experimental group was significant higher than that in control group(1.426±0.216 and 0.67±0.23 vs 1±0.158 and 0.40±0.08, P<0.05). The expression of telomerase protein was significant lower in experimental group (0.64±0.19) than that in control group(0.87±0.12,P<0.05).However, the expression of POU5F1 mRNA showed no significant differences between the two groups (p>0.05). Conclusion Our data suggests that chronic ischemia and chronic endometrial ischemia-associated decreased expression of c-kit and telomerase and increased expression of caspase3 may be responsible for the pathogenesis of thin endometium.Conclusion1. A rat model of chronic endometrial ischemia was induced by performing bilateral uterine artery ligation.2. The Pathophysiologic changes of this model are consistent with pathology of patients with thin endometrium,which can serve as a nice model for chronic endometrial ischemia.3. Chronic ischemia and decreased expression of c-kit and telomerase and increased expression of caspase3 may be responsible for the pathogenesis of thin endometium.
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