The Expression And Significance Of LIF And BFGF In The Ovary Of Rat's Polycystic Ovarian Syndrome

ObjectivePolycystic ovarian syndrome (PCOS) , mainly featuring the androgen excess and the chronic anovulation, is one of the most common endocrine disorder diseases among the women of childbearing ages. The incidency rate of it accounts for 5%-21% among the infertility women and 75%-80% among the anovulatory women. In 1935, Stein and Leventhal initially reported a group of syndrome principally characterizing amenorrhea, obesity, hirsutism, anovulation and the bilateral ovarian Polycystic changes. Due to the very extensive changes of physiopathology which involves in genetics, neuroendocrinology, glycometabolism, adipic-metabolism, protein-metabolism and the abnormality of local regulating and controlling factors of ovary, its research is still remained one of the hotspots in Gynecological endocrinology field by now. In previous reports,it has been suggested that the functional disorder of some local cytokines in the ovary is the important component of pathogenesis of PCOS ,the function of Leukemia inhibitory factor (LIF) and Basic fibroblast growth factor (bFGF) are two kinds of important local regulatory factors in the ovary, few reports about the expression of LIF in the ovary of PCOS are read , no report about the expression of bFGF in the ovary of PCOS is read.LIF is a kind of secreting type protein which is saccharified highly, belongs to IL-6 family. It has Extensive biological function. LIF plays the role in the process of reproduction including growth and development of follicle,ovulation,growth, development,differentiation,nidation of embryon ,and so on .bFGF is a kind of polypeptide growth factor, It has Extensive biological function, bFGF regulate development and select of follicle and improve ovulation, and development of embryon,and so on.In our study, we set up a rat's model of PCOS using letrozole , evaluate the model of PCOS by estrous cycle changing ,serum sex gonadal hormone determination and ovary change in anatomy and histology, and investigate the expression of LIF and bFGF in the ovary by using immunohistochemical methods, so as to discuss the function of LIF and bFGF in the pathogenesis of Polycystic ovary syndromeMaterial and Methods1. ObjectorSixty clearing class SD female rats (42 days) with 4 days regular estrus cyclewere divided into three groups, including a treatment group of twentyrats ,experimental control group of twenty rats and a blank control group of twentyrats. All rats are provided from experimental animal center of ZhengZhou university(Produce licence number: SCXK (YU) 2005—0001) .2 .Methods2.1 To make animal model of PCOS: The treatment group was administered by letrozole at concentration of 1mg/kg P.o. dissolved in 1 % aqueous solution of carboxymethylcellulose (CMC ) once daily, while normal control group was received vehicle only 1% CMC once daily orally and blank control group was received nothing. The treatment period was 23 days. During this period, vaginal smears were collected daily for estrus cycle determination.2.2 To obtain samples: On the day subsequent to last letrozole dose administration, all animals (fasting 12 hours) were sacrificed by absence of blood. Heart blood was obtained and serum were kept in a freezer at -40℃for subsequent hormone determination with radioimmunoassay (RIA) .Uterus and ovaries were excised and weighed to evaluate the effect of the test compound on endocrine balance of animals.2.3 Histology detection in ovaries: Ovaries were cut through at longest longitudinal dimension and fixed in 10% neutral formalin, serially sectioned at 4 urn, and stained with hematoxylin and eosin.2.4 Detection with RIA: Using RIA, subsequent hormone determination [ luteinizing hormone (LH ), follicle-stimulating hormone (FSH), estradiol (E₂), prolactin (PRL) , and testosterone (T) ] were fulfilled.2.5 To analyse the expression of LIF and bFGF in ovary by using immunohistochemical methods.3. Statistical analysisThe data was calculated using mean±SD. The mean of each group of rat was Compared by one-way ANOVA. SPSS 11.5 was used for studies. P < 0.05 was considered significant.Results1. The estimation of Rat's Model for PCOS1.1 The Estrus cycles of letrozole treatment group after administering letrozole 12 days showed irregular change, which indicated that the rats had no ovulation.1.2 The treatment group brought about raising ovarian weight (P<0.05 ) and reduction of uterine weight (P<0.05) . In treatment group, it is possible to see the early development of little follicles, atretic follicles and the abundance of subcaplular ovarian cyst lined with a thin layer of granulosa cells. It is also can be seen the decreased number of corpora lutea with incomplete luteinization. The normal control group and blank controle group can be seen more complete corpora lutea and different levels of follicles with thicken layer of granulosa cells.1.3 In treatment group, although serum estradiol and FSH levels were reduced (P<0.05) ,testoterone levels were elevated as were levels of LH and serum PRL (P<0.05)2. The exPression of LIF and bFGF in the ovary LIF and bFGF both expresss in interstitial cell,granular cell and theca cell .Expression of LIF in interstitial cell,granular cell and theca cell of the treatment group was significantly lower than those observed in the experimental control group and blank control group (P<0.05 ) separately; Expression of bFGF in theca cells of the treatment group was significantly higher than those observed in the experimental control group and blank control group (P<0.05 ) .Conclusions1. Letrozole-induced model in rats can be served as the ideal model of PCOS, which has high dependability and is prior to the used PCOS model in our country.2. The expression of LIF and bFGF in the ovary close is highly correlated with the originated mechanism of PCOS.