The Study Of The Protective Effects Of GnRHa On Chemotherapy-induced Ovarian Premature Failure In Rats

Along with the development of life science, developing and applying form of combined therapy of tumour, the long-term survival rate of cancer patients has improved. Because chemotherapy is applied a great quantity,it often induces a series of long-term and short-term complications.The damage of the ovarian and the premature ovarian failure is one of the clinical frequent long-term side effect of chemotherapy. Because of the limited quantity of ovaries germinal cell and irreproducibility , premature ovarian failure often happens , and causes menstruation irregularis, infertility, premature menopause, perhaps complicating hectic fever, night sweat, osteoporosis , symptoms of uropoietic and cardiovascular system and so on.Premature ovarian failure and infertility influence young women's self-respect and the quality of their life greatly. With the purpose of further raising patients'living quality,it needs badly to prevent the damage of the ovarian from chemotherapy.In this study,we investigate the damage of the ovarian from DDP,and research the protective effects and mechanisms of GnRHa on chemotherapy-induced rats ovarian functional lesion, to provide more breadboard evidence for further clinical research.Part 1. The study of the protective effects of GnRHa on ovarian function of rats given chemotherapy.Sixty 2-3 months female SD rats whose body weights were between (250±10)g were randomized into six groups of ten animals each group, the normal control group,CTX group,DDP group,GnRHa group, GnRHa+CTX group, GnRHa+DDP group. All rats in this study were administered by peritoneal injection for 20 d.The rats were sacrificed on the day of dioestrus stage.Body weights, ovaries weights,uterus weights and morphological diversity were observed.Serum estradiol(E2) and follicle stimulating hormone(FSH) were detected with the radio immunoassays. Histologic changes of ovaries were observed by light microscope.A quantitative analysis of different stage follicles and total follicles were conducted.Results:①Body weights,ovaries weights and uterus weights were different between six groups after treatment. Those items in rats treated with DDP 20mg/(kg·d) group were significantly reductive comparing with the control group(P<0.05). There was no significantly difference between GnRHa group and the control group(P>0.05).②DDP treatment produced a significant reduction in the number of different stage follicles(P<0.05).In the DDP group,it was found that cortex of ovary was thickening, structural confusion, interstitial fibrosis, cellular anaplasia and reduction in vascularity。GnRHa reduced the number of secondary follicle and mature follicle ,but GnRHa treatment resulted in preserving of most primary follicle and a small quantity corpora atretica. GnRHa group was not observed interstitial fibrosis.In GnRHa+DDP group,it was observed increase in the number of primary follicle (P<0.05), reduction in the number of secondary follicle and mature follicle ,the level of tissular fibration was reduced comparing with DDP group.There was no obviously hemorrhage and necrosis.③Serum follicle stimulating hormone(FSH) was significantly elevation and estradiol(E2) was decreased in DDP group(P<0.05).There was no significant differences between the GnRHa+DDP group and the control group(P>0.05).The results showed that DDP obviously injured ovarian function, and GnRHa was given in antephase can protect ovaries from chemotherapy-induced ovarian damage.Part2.Study the mechanism of protective effects of GnRHa against chemotherapy-induced gonadotoxicity in female rats.The grouping was identical with part 1.The apoptosis of granular cells in all groups were detected by TUNEL. Bcl-2 and Caspase-3 in the ovary were examined with the SP immunohistochemical method.The expressions of Estrogen receptor(ERβ) and progesterone receptor(PR) in ovary tissue were measured using the SP immunohistochemical method. Results:The apoptosis percent of granular cells in DDP group was significant higher than the control group and the GnRHa+DDP group(P<0.05). In DDP group,Bcl-2 protein expression significantly decreased, and Caspase-3 gene expression was significantly higher than the GnRHa+DDP group(P<0.05). About the expression of ERβand PR,no significant difference was found between one group and another (P>0.05).Conclusion: GnRHa+DDP can restrain apoptosis through up-regulation of Bcl-2 and reduction of Caspase-3.However, GnRHa can not change the expression level of ERβand PR in ovaries.It is estimated that the protective effect of GnRHa against chemotherapy-induced POF in female rats was independence with the expression level of ERβand PR.