Expression And Significance Of Angiotensin Receptors In Ovarian Tissue Of Polycystic Ovarian Syndrome Rat Model

Objective: Through detection the expression level of angiotensinreceptors of renin-angiotensin system’s two axis (ACE-AngⅡ-AT1/AT2axisand ACE2-Ang-(1-7)-MAS axis) in the ovarian tissue of polycystic ovarysyndrome rat model, we observe the difference and the relationship betweenPCOS and normal ovarian tissue, in order to providing a new thinking for thepathogenesis of polycystic ovarian syndrome and therapeutic approaches.Methods:1Experimental animals and groups1.1Experimental animals:85-day-old female Sprague Dawley rats.(Fig.1)1.2The control group:20SD rats; The model group:20SD rats。2MethodsThe PCOS rat’s model was experimentally induced by insulin0.5iu up to6.0iu and human chorionic gonadotrophin hormone (HCG)6.0iu forcontinuous22days.2ml of distilled water was given for an equivalent lengthof time to rats in the control group. All rats were killed by breeding after22days, and the ovarian and uterine tissues were obtained.3Sample collection and measure3.1Sample collection: At first, taking rat’s blood in heart and separating serumto measure the level of insulin (INS) and testosterone (T).Next, after openingrat’s belly cavity, we looked for ovary and uterus and observed theirconfiguration, then, separated tissue to measure ovarian weight. The last, weused4%par formaldehyde to reserve a part of ovarian and uterine tissue andpreserve other portion which was flushed by physiological saline in liquidnitrogen.(Fig.2,Fig.3)3.2Sample measure: The level of insulin (INS) and testosterone (T) of rats’blood were measured by chemiluminescence. The expression of AT1, AT2and Mas were analyzed by Fluorescence quantitative PCR (RT-PCR), the graydegree of sections was determined by image analysis system.Results: The level of insulin (INS) and testosterone (T) of model ratsblood raised up apparently by using Poresky method after22days, in addition,17rats of total20rats showed durative keratinocyte on vaginal smears duringthe period.1The changes of blood hormone in two group ratsThe blood hormones (T and INS) level in control group were(4.01±7.62)nmol/L and (6.93±2.81)U/L, while in model group were(13.17±12.25)nmol/L and (28.59±5.32)U/L. The mean level of insulin andtestosterone in PCOS model group was significantly higher than that ofcontrol group (P<0.01).(Table1)2The changes of ovarian weight in two group ratsThe ovarian weight in control group was (0.0258±0.0017g), while modelgroup was (l0.1306±0.0094g). The mean level of ovarian weight in PCOSmodel group was significantly higher than that of control group (P<0.01)(Table2).3The morphological changes of ovaries in two group ratsIn the control group, the ovarian tissue were red with more corpus luteumand many follicles in different development stages under microscope, thedominant follicles were with8to9layers of granulose cells. The ovariantissues of the model group were paler than that of control group, but ovarianvolume was significantly larger.(Fig.4)4The morphological changes of endometrial tissueThe endometria of control group rats had a lot of large multi-fold glands,with cluster-like arrangement, and secretory vesicles. The uterus of modelgroup was more paler and uterus volume was significantly larger, with serelyreduced number of endometrial glands, glandular cavity were arrangeddispersed and straight.(Fig.5)5The results of AT1, AT2and MAS mRNA by RT-PCR5.1The expression of AT1mRNA AT1mRNA expression in ovarian tissue of PCOS rats and normal ratswere0.87±0.12,0.43±0.20. The level of AT1mRNA in the ovarian tissue ofPCOS rat was obviously higher than that of normal rat, with significantdifference (P<0.01).(Table3)5.2The expression of AT2mRNAAT2mRNA expression in ovarian tissue of PCOS rats and normal ratswere0.85±0.16,0.53±0.17. The level of AT2mRNA in the ovarian tissue ofPCOS rats was obviously higher than that of normal rats,and the differencewas statistically significant (P<0.01).(Table4)5.3The expression of MAS mRNAMAS mRNA expression in ovarian tissue of PCOS rats and normal ratswere0.69±0.29,0.38±0.28.The level of MAS mRNA in the ovarian tissue ofPCOS rats was obviously higher than normal rats, and the difference wasstatistically significant (P<0.05).(Table5)Conclusions: Expression of AT1, AT2and MAS were enhanced inovarian tissue of PCOS rat model, which may take part in folliculogenesis,steroid genesis, oocyte maturation, and ovulation obstruction and mayparticipate in the pathological process of PCOS.