| Objective: Polycystic ovarian syndrome (PCOS) is a frequentendocrine secretion disease in the femme of reproductive age, its incidencerate is5%~10%. Its clinical features are persistent anovulation,hyperandrogenism and hyperinsulinemia. Ovalle reported that about50%to70%patients with PCOS are having varying degrees of insulin resistance.The development mechanism of PCOS is not very clear, and it is difficult toconduct controlled studies in humans. This study was designed to examinethe relationship between insulin receptor substrate and PCOS.Methods:1Experimental animals and groups1.1Experimental animals:85-day-old female Spragu Dawley rats.(Fig.1)1.2The blank control group:10SD rats;The model control group:20SDrats;The metformin group:20SD rats.2MethodsThe PCOS rats model was experimentally induced by insulin0.5iu upto6.0iu and human chorionic gonadotrophich hormone(HCG)6.0iu forcontinuous22days. Give metformin3mg/kg to the metformin groupcontinuous22days.2ml of distilled water was given for an equivalent lengthof time to rats in the blank control group and model control group. All ratswere killed by bleeding after22days, and the ovarian and uterine wereobtained.(Fig.2,Fig.3,Fig.4)3Mensurate the sampleUsing Chemistry illuminate method to mensurate insulin andtestosterone (T) of the rats blood. The expression of IRS-1,2andphosphorylation of tyrosine phosphokinase were analyzed by immunohisto chemistry. The gray degree of sections was determined by image analysissystem.Results:1The changes of hormone in different groupsThe mean of insulin and testosterone in model control group comparedwith blank control group was significantly higher(P＜0.01),and the mean ofinsulin and testosterone in metformin group compared with model controlgroup was lower(P＜0.05).(Table1)2The changes of ovarian weight in three group ratsThe blank control group was (0.0258±0.0017g), the model contro groupwas (l0.1306±0.0094g), and the metforminl group was (0.0641±0.0083g).3The morphological changes of ovaries.(Table2)The ovaries of the blank control group were red with corpus luteum.Through the microscope to see more corpus luteum and many follicles indifferent development stages. The dominant follicles can be seen8to9layers of granulosa cells. The ovaries of the model control group were palerthan the ovaries of the blank control group, and ovarian volume wassignificantly larger. Through the microscope to see cystic dilatation offollicle without the basic structure, only seeing1to2layers of granulosacells and atretic follicles. The ovaries of the metformin group were red withcorpus luteum. Through the microscope to see follicles in differentdevelopment stages and corpus luteum. The dominant follicle had basicstructures and many granulosa cells.(Fig.5)4The morphological changes of endometrialThe blank control group rats had many endometrial glands that werecluster-like arrangement with large gland and multi-fold, and the glandularepithelium had secretory vesicles. The uterus of the model control groupwere more pale than the uterus of the blank control group, and uterusvolume was significantly larger. The number of endometrial glands weresignificantly reduced, and glandular cavity that arranged dispersed was smalland straight. The uterus of metformin group were smaller than the uterus of the model control group, and the number of endometrial glands in metformingroup was larger than in model control group. The glandular cavity that wascluster-like arrangement was small and straight.(Fig.6)5The immunohistochemical staining results5.1The grey levels of endometrial IRS-1in blank control group, modelcontrol group and metformin group were (68.96±12.73),(139.66±3.04) and(80.46±7.68), Grey IRS-1in the model control group was significantly lowerthan in the blank control group(P＜0.01). Grey IRS-1in the metformingroup was significantly higher than in the model control group (P＜0.01),but still lower than in the blank control group(P＜0.05).(Fig.7,Table3)5.2The grey levels of endometrial IRS-2in blank control group, modelcontrol group and metformin group were (98.80±1.59),(123.33±5.62) and(104.71±8.97), Grey IRS-2in the model control group was significantlylower than in the blank control group(P＜0.01). Grey IRS-2in themetformin group was significantly higher than in the model control group(P＜0.01),but still lower than in the blank control group(P＜0.05).(Fig.8,Table3)5.3The grey levels of tyrosine phosphorylation of endometrial IRS-1inblank control group, model control group and metformin group were(75.64±4.67),(125.16±22.35) and (97.44±9.11), Grey P-tyr(IRS-1) in themodel control group was significantly lower than in the blank control group(P＜0.01). Grey P-tyr(IRS-1) in the metformin group was significantlyhigher than in the model control group (P＜0.01),but still lower than in theblank control group(P＜0.05)；The grey levels of tyrosine phosphorylationof endometrial IRS-2in blank control group, model control group andmetformin group were (68.10±8.36),(131.75±10.41) and (102.86±3.77),Grey P-tyr(IRS-2) in the model control group was significantly lower than inthe blank control group(P＜0.01). Grey P-tyr(IRS-2) in the metformingroup was significantly higher than in the model control group (P＜ 0.01),but still lower than in the blank control group(P＜0.05).(Fig.9,Table3)5.4The grey levels of ovaries IRS-1in blank control group, model controlgroup and metformin group were (102.63±3.59),(54.07±13.33) and(89.42±7.20),Grey IRS-1of ovaries in the model control group wassignificantly higher than in the blank control group(P＜0.01),Grey IRS-1inthe metformin group was significantly lower than in the model control group(P＜0.01),but still higher than in the blank control group(P＜0.05).(Fig.10,Table4)5.5The grey levels of ovaries IRS-2in blank control group, model controlgroup and metformin group were (98.42±4.57),(103.16±10.83) and(105.29±9.65),the protein expression of IRS-2did not change in threegroups.(Fig.11,Table4)5.6The grey levels of tyrosine phosphorylation of ovaries IRS-1in blankcontrol group, model control group and metformin group were(97.46±2.61),(136.39±17.71) and (112.15±8.94),Grey P-tyr(IRS-1) ofovaries in the model control group was significantly lower than in the blankcontrol group(P＜0.01)and Grey P-tyr(IRS-1) of ovaries in the metformingroup was significantly higher than in the model control group(P＜0.01);The grey levels of tyrosine phosphorylation of ovaries IRS-2in blankcontrol group, model control group and metformin group were(104.90±6.35),(154.78±21.06) and (123.31±4.76), Grey P-tyr(IRS-2) ofovaries in the model control group was significantly lower than in the blankcontrol group(P＜0.01)and Grey P-tyr(IRS-2) of ovaries in the metformingroup was significantly higher than in the model control group(P＜0.01).(Fig.12,Table4)Conclusions:1There is a selective insulin resistance in endometrium and ovarian frompatients with PCOS, the reason may be related to abnormal tyrosinephosphorylation and protein expression of insulin receptor substrates. 2Metformin improves endometrium and ovarian function of PCOS, thereason may be related to correct the abnormal protein expression andimprove the tyrosine phosphorylation of insulin receptor substrates inendometrium and ovarian. |
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