The Expression And Significance Of CTGF And MMP-9 In The Ovary Of Rat's Polycystic Ovarian Syndrome

Background and objectivesPolycystic 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 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 partial regulating and controlling factors of ovary, its research is still remained one of the hotspots in Gynecological endocrinology field by now.Many of PCOS are anovulation,very few can have oligotrichia ovulation or luteal phase defect. Now, thelocal mechanisms underlying the dysfunction of follicular development in pcos remain obscure. 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 connective tissue growth facto(CTGF)and matrix metalloproteinases-9(MMP-9)are two kinds of important local regulatory factors in the ovary, few reports about the expression of MMP-9 in the ovary of PCOS are read , no report about the expression of CTGF in the ovary of PCOS is read.CTGF extensively expressed in kidney heart and Liver etc organ, It can promote cell proliferation, cell adhesion and resulted extracellular matrix (ECM) and collagen to synthesize,and involved embryonic development, tissue differentiation, repair in trauma,.and tissue fibrosis.Matrix metalloproteinases(MMPS) are a kind of zinc protease. It can breakdown ECM, having important roles in the reverse and remodeling of ECM in organism.MMP-9 is the one of in MMPS.MMP-9 belongs to IV Collagenase. It degradationIV V collagen and elasticin. Collagen is key component of ECM. MMP-9 can promoted the ECM disintegration.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 CTGF and MMP-9 in the ovary by using immunohistochemical methods, so as to discuss the function of CTGF and MMP-9 in the Pathogenesis of polycystic ovary syndrome.Materials and Methods1. ObjectsSixty clearing class SD female rats(42 days) with 4 days regular estrus cycle were randomly divided into three groups (20 rats for each group): Experiment group ,normal control group and a blank control group. All rats were provided from experimental animal center of Zhengzhou univercity[produce licence number: SCXK(YU)2005—0001].2. Methods(1) Make animal modle of PCOS: The experiment group was administered letrozole at concentration of 1mg /kg/d p.o. dissolved in 1% aqueous solution of carboxmethly cellulose (CMC) once daily, while normal control group received vehicle only 1 % CMC once daily orally and blank control group received nothing. The treatment period was 23 days. During this period, vaginal smears were collected daily for estrus cycle determination.(2) Obtain samples: On the day subsequent to last letrozole dose administration, all animals were killed by absence of blood. Heart blood was obtained and sera were kept in a freezer at -40℃for subsequent hormone determination [follicle-stimulating hormone (FSH) , luteinizing hormone (LH) , estradiol (E₂) , prolaction (PRL) and testosterone (T) ].Uteri and ovaries were excised and weighed to evaluate the effect of the test compound on endocrine balance of animals.(3) Histologic detection of ovaries: Ovaries were cut at longest longitudinal dimension and fixed in 10% neutral formalin, sectioned at 4μm,and stained with hematoxylin and eosin.(4) Detection by RIA: Subsequent hormone determination (LH ,FSH, E₂, PRL and T) were detected.(5) Detected the expression of CTGF and MMP-9 in Ovary tissue by using immunohistochemistry3. Statistical analysisThe data was calculated using mean±SD. Comparisons amomg different groups of patients was undertaken using Analysis of Variance .SPSS 10.0 was used for both studies. There was a statistical significance when p<0.05.Results1. The estrus cycles of the experiment group showed irregular change, which indicated that the rats had no ovulation.2. The experiment group brought about rasing ovarian weight and suppression of uterine weight.3. In experiment 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 control group can be seen more complete corpora lutea and different levels of follicles with thicken layer of granulosa cells.4. In experiment group, although serum E₂ and FSH levels were reduced, T levels were elevated as levels of LH and PRL were .5. In experiment group, the level of the expression of CTGF were obviously elevated in follicular basic membrane, primordial follicle, preantral follicle and albuginea of the rats with PCOS. while the level of the expression of MMP-9 were obviously degraded in follicular basic membrane and obviously elevated in luteinization granule cells of the rats with PCOS. 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 CTGF and MMP-9 in the ovarian is highly correlated with the pathogenesy of PCOS.