The Expression Of MicroRNA In The Ovary Of Polycystic Ovary Syndrome Rat Model

Part I The construction of rat model with polycystic ovary syndrome (PCOS) and microRNA (miRNA) expression pattern in the ovary of polycystic ovary syndrome rat modelObjective:1,To establish the polycystic ovary syndrome (PCOS) rat model with the juvenile female Wistar rats by dehydroepiandrosterone (DHEA), and to observe the changes of ovarian morphology, sex hormone and insulin resistance.2,To investigate the differentially expressed miRNA in the ovary of rats with PCOS by use of miRNA microarrays, to explore the relationship between pathogenesis and miRNA aberrantly expressed in PCOS rat model.Methods: 1,Forty female Wistar rats of 21 days old were randomly divided into two groups (n=20 each): model group and control group. The rats of model group were subcutaneously injected with 6mg/100g weights DHEA and 0.2ml oils for 20 days, and the control group rats were subcutaneously injected with 0.2ml oil at the same time. Prove the model with the methods as follow: Determine the stage of cyclicity by microscopic analysis of the predominant cell type in vaginal smears. Detect testosterone, estradiol, luteinizing hormone levels, and fasting insulin (FINS) levers by radioimmunoassay (RIA). Detect fasting blood glucose (FBG) by blood glucose monitor, and calculate the insulin resistant index (HOMA1-IR). View ovarian morphological changes by HE stain, and measure the ovarian weights and body weights.2,Anesthetize each rat and ovaries were obtained, catheters were inserted into the heart of the rats for blood sampling and collect serum. Measure the expression profiling of miRNA in the ovary of rats by miRNA microarrays, and analyze the difference between PCOS group and control group.Results:1,Rats in control group had regular cycles, while rats in model group had irregular cycles. The serum level of testosterone, fasting insulin, fasting blood glucose concentration were significantly higher in model group than those in control group(P<0.01, P<0.01, P<0.01),and so as the insulin resistance index (P<0.01). The body weight in two groups showed no significant differences (P>0.05). In consideration of body weight influence, the ovarian weight in model group were higher than the control group (P<0.05). The HE stain of ovarian slices showed that the number of follicular cysts were increased, While the developing follicles, corpus lutea (CL) and GCs were significantly diminished in the model group. There are many CL and developing follicles in different stages in the control group. 2,Compared with control group, forty eight miRNA were differentially expressed. Twenty two miRNA were upregulated, include miR-320, miR-296, miR-323*, miR-330, miR-145 and so on. Twenty six miRNA were downregulated in the ovary of PCOS rats, miR-21, miR-10b, miR-290, miR-352, miR-146b and so on.Conclusion:1,The changes of the ovarian morphology and sex hormone in the PCOS rat model induced by DHEA were proved to be similar with that of the PCOS patients, and the rat model also has insulin resistance.2,The expression pattern of miRNA showed significant difference in the ovaries between PCOS model group and control group. The aberrant expression of miRNA may be involved in the pathogenesis of polycystic ovary syndrome.Part II The expression of miR-21 and miR-320 in the ovary of rats and explore their function in the pathogenesis of PCOSObjective:1,To confirm the expression of miR-21 and miR-320 in the ovary of rats with PCOS and the rats in the control group, and to further verity the results of miRNA microarrays.2,To compare the expression levels of miR-21, miR-320 in the ovary of rats with PCOS and the rats in the control group respectively, analyze the role of miR-21 and miR-320 in the pathogenesis of polycystic ovary syndrome.Methods: The levels of miR-21 and miR-320 in the two groups were detected by real time quantitative polymerase chain reaction (Real-time PCR).Results:Compared with the control group, the level of miR-21 in the ovary of rats was decreased in the model group (P<0.01), but the level of miR-320 was increased (P<0.01). The variation tendency is consistent with the results of miRNA microarray.Conclusion:Indeed miR-21 and miR-320 were expressed in the ovary of rat, and their expressions between the two groups showed significant difference. It is indicated that miR-21 and miR-320 may participate in the pathogenesis of polycystic ovary syndrome.