Study Of The Influence Of Melatonin On Cryopreserved Heterotopic Transplanted Ovarian Tissues In Rats

Part1The short-term influence of timing of melatonin injection on cryopreserved-autotransplanted ovarian tissueObjectiveTo investigate the short-term effect of different injection timing of melatonin on cryopreserved-autotransplanted ovarian tissue.MethodsThe SD rats were randomly distributed into four groups based on the timing of melatonin injection:Control group:no melatonin treated during the procedure, same dose of saline instead. Pre-cryopreserved group: intraperitoneal injection of melatonin on the dose of20mg/kg×2days before ovarian cryopreservation. Post-transplanted group:intraperitoneal injection of melatonin on the dose of20mg/kgX2days after frozen-thawed ovarian tissues autotransplanted into leg muscles. Pre-cryopreserved and post-transplanted group:the rats were treated as both pre-cryopreserved group and post-transplanted group. SOD、MDA and GSH-PX in the transplanted ovarian tissues were assayed to evaluate the function of melatonin as an antioxidant. Follicle counting was used to estimate the protection role of melatonin to the ovarian tissue.Results1. GSH-PX activity was significantly higher than control group in pre-cryopreserved group, as well as in pre-cryopreserved and post-transplanted group.The content of MDA was significantly lower in pre-cryopreserved group. There were statistically significant differences. SOD activity made no significant difference between groups.2. Follicle number decreased after frozen-thawing procedure, and declined further after transplantation for48hours. Constituent ratios of follicles made no significant difference between groups. Frozen-thawed procedure and ischemic injury were more damaging to antral follicles than the others.ConclusionMelatonin can enhance the antioxidant defense of frozen-thawed ovarian tissue. However, the residual rate of follicle was not influenced in short term. The protection can be achieved if melatonin was injected before cryopreservation or both before cryopreservation and post transplantation.Part2The medium and long-term influence of melatonin on ovarian tissue heterotopic transplanted to different sitesObjectiveTo explore the impact of melatonin on ovarian tissue autografted to kidney capsule, neck subcutaneous tissue or leg muscle after30days.MethodsThe SD rats were randomly distributed into kidney capsule, neck subcutaneous tissue and leg muscle groups based on different graft sites. Each group was divided into two subgroups based on whether melatonin was treated. The ovarian tissues were collected at30th day after transplantation. Estrous cycle was monitored by colpocytological examination. Serum E2level was determined to assess the reproductive endocrine function. Follicles were counted to estimate the folliculogenesis and oocyte maturation capacity.Results1. All rats could restore the estrous cycle on the7th-9th day after transplantation except2rats in the neck subcutaneous tissue group. The estrous cycle was4-5days. The regular estrous cycle could lasted until the tissue collection time.2. Serum E2levels were equal between groups, regardless of whether melatonin was injected.3. All groups could retain relatively normal ovarian structure. Constituent ratio of follicles after transplantation was significantly different from that before cryopreservation. The percentage of antral follicle was increased. Ovarian tissue transplanted under kidney capsule treated with melatonin had more mature follicles than controls, and there were statistically significant differences.ConclusionThere is no obvious influence of melatonin on serum E2level. Melatonin can promote follicle maturation of ovarian tissue transplanted under kidney capsule. Kidney capsule and leg muscle might be better graft sites than neck subcutaneous tissue.SummaryThe ovarian tissue can endure the frozen-thawed procedure and keep reproductive endocrine function. Kidney capsule and leg muscle might be better graft sites than neck subcutaneous tissue.Melatonin can enhance the antioxidant defense of frozen-thawed ovarian tissue. However, the residual rate of follicle was not influenced in short term. The protection can be achieved if melatonin was injected before cryopreservation or both before cryopreservation and after transplantation, but the pre-cryopreserved treatment is better.Melatonin can promote follicle maturation of ovarian tissue transplanted under kidney capsule.