Comparison of two kinds PCOS animal models and the expression of VEGF and ET-1 in ovarian tissue

Abstract

Objective To compare the two established rat models induced by dehydroepiandrosterone(DHEA) and letrozole, discuss the expression of vascular edothelial growth factor(VEGF) and endthelin ET-1 of polycystic ovarian syndrome(PCOS) rat model induced by letrozole. Methods ①By measuring serum level of sex hormone and observing the variation of ovarian morphology, the effectiveness of the two modeling methods was compared; ②Screening of letrozole made relatively close to the clinical characteristics of PCOS module, immunohistochemical method was used to detect VEGF and ET-1. Results ①Compared with control group, serum level of testosterone[(3.147±0.780)ng vs(2.221±0.551)ng, P=0.007]、follide-stimulating hormone(FSH)[(6.666±2.260)ng/mL vs(4.327±0.949)ng/mL, P=0.011] were increased, luteinzing hormone(LH)[(4.188±1.633)mIU/mL vs(6.014±1.617)mIU/mL, P=0.022]estradiol(E2)[(95.08±9.899)pmol/L vs(129.75±17.91)pmol/L, P=0.000] and progestogen(P)[(86.00±8.730)nmol/L vs(166.76±30.04)nmol/L, P=0.000]were decreased in group DHEA, and the results had statistical significance(P<0.05). In group DHEA, the quality and volume of ovary were significance smaller than those in control, under the microscope, a small amount of follicular at all levels, mature follicle were found, the granular cell layer decreased to 5~6 layers theca cells and mesenchymal cells were proliferated less obvious .Compared with control group, serum levels of T[(15.829±4.103)ng/mL vs(7.524±4.208)ng/mL, P=0.000]and LH[(8.416±5.629)mIU/mL vs(5.629±2.094)mIU/mL, P<0.05]were significance increased, the ovary mass was also increased in group letrozole. In group letrozole, under the microscope, there were multiple cystic expansion of follicles, the granular cell layer decreased to 2~3 layers and the oocyte or corna radrata in follicle was nearly disappeared. Based on the variation of serology and ovarian morphology, the model induced by letrozole is more similar to human PCOS; ②In letrozole module ovarian tissue, VEGF and ET-1 presented a high level(P<0.05). Conclusion the model induced by letrozole is more similar to human PCOS, and in ovarian tissue, VEGF and ET-1 presented a high level which may participate in the occurrence of PCOS. Key words: Polycystic ovarian syndrome; Vascular ezothelial growth factor; Endothelin-1; Angiogenesis