Effects Of Acarbose On Kisspeptin Expression In Hypothalamic Arcuate Nucleus Of PCOS Rats

Objective: Polycystic ovary syndrome(PCOS)is a common complicated disease of reproductive dysfunction and endocrine metabolic abnormalities in women.Its important pathophysiological basis is the disorder of the hypothalamic-pituitary-gonadal(HPG)axis.Recently Kisspeptin has been considered as a new bridge between energy metabolism balance and reproductive function,which is closely correlated with the onset and progress of PCOS.In this study,the PCOS rat model was induced by letrozole gavage to study the relationship between Kisspeptin expression and reproductive endocrine metabolism,as well as the effect of acarbose on Kisspeptin expression,so as to explore new therapeutic directions for PCOS.Methods: After 3 days of adaptive feeding,45 female healthy SD rats were divided into model group(30 rats)and control group(15 rats).The model group was given letrozole to establish PCOS rat model,while the control group was given normal saline for the same period,weighed every 7 days,and the estrous cycle of all rats was monitored every day from the 19 th day of modeling.After the modeling,appropriate amount of rats were randomly selected from the model group with estrous cycle disorder and the control group to observe the ovarian histomorphology to verify the model.After the evaluation of successful modeling,the rats in the model group were randomly divided into PCOS group(9 rats)and acarbose group(10 rats),and the remaining rats in the control group were divided into normal saline group(9 rats).The rats in acarbose group were given acarbose for 21 days,while the rats in PCOS group and normal saline group were given normal saline intragastric administration,and the body weight and estrous cycle of the rats were monitored.After excluding the rats that died during the experiment,a total of 24 female SD rats were included in the statistical results and sampling,with 8 rats in each group.After drug treatment,abdominal glucose tolerance test was carried out to observe glucose tolerance,serum sex hormone and insulin levels of rats were detected,and the changes of ovarian histology were observed and compared.Immunohistochemical staining and fluorescence in situ hybridization were used to detect Kisspeptin protein expression and Kiss1 m RNA level in arcuate nucleus.After the experiment,SPSS 25.0,Image J and Graph Pad Prism 9.0 were used for statistical analysis,image processing and plotting.Results:(1)After letrozole modeling,the body weight of the rats in the model group was noteworthily higher than that in the control group(P<0.01).After acarbose treatment,the weight change of rats in the acarbose group was less than that in the PCOS group(P<0.05).(2)The estrus cycle of PCOS rats was disordered and kept in the diestrus period.The estrus cycle of the rats in the acarbose group was recovered,but the changes of each phase and the length of the cycle were still not quite regular,while the rats in the saline group showed a complete and regular estrus cycle.(3)In the intraperitoneal glucose tolerance test,the area under the curve(AUC)of blood glucose value in PCOS rats was larger than that in saline rats(P<0.05).The AUC of blood glucose in the acarbose group was lower than that in the PCOS group(P>0.05).The rats in the PCOS group had impaired glucose tolerance.(4)Fasting blood glucose(FBG),fasting insulin and HOMA-IR of PCOS group were noteworthily higher than those of normal saline group(P< 0.01),insulin resistance appeared in PCOS rats.FBG,fasting insulin and HOMA-IR of acarbose group were lower than those of PCOS group(P<0.05)and insulin resistance was improved.(5)The ovaries of PCOS rats showed polycystic changes,and the number of normal follicles and corpus luteum decreased(P<0.05),the number of cystic follicles increased significantly(P<0.01)and the ovarian index increased(P<0.05).The polycystic changes of ovary in acarbose group were improved,the number of corpus luteum increased,and the number of cystic follicles decreased(P<0.05),the ovarian index decreased significantly(P<0.01).(6)Serum levels of testosterone and luteinizing hormone in PCOS group were significantly increased(P<0.01),hyperandrogenemia and high LH were present.Serum testosterone and luteinizing hormone levels of rats in acarose group were decreased(P<0.05).(7)The number of Kisspepetin positive cells in hypothalamic arcuate nucleus of rats in PCOS group was significantly higher than that in normal saline group(P<0.01),the number of Kisspepetin positive cells in acarbose group was significantly lower than that in PCOS group(P<0.01).(8)The positive expression level of Kiss1 m RNA in hypothalamic arcuate nucleus of rats in PCOS group was noteworthily higher than that in normal saline group(P<0.01),the positive expression level of Kiss1 m RNA in acarbose group was lower than that in PCOS group(P<0.05).Conclusions: The PCOS rat model induced by intragastric administration of letrozole is an ideal model for studying the reproductive and endocrine metabolic dysfunction of human PCOS.The expression of Kiss1 gene in the hypothalamic arcuate nucleus of PCOS rats is changed,which may be involved in the pathophysiological process of the disorder of HPG axis and reproductive and endocrine metabolic dysfunction.Acarbose may inhibit the expression of Kiss1 gene in hypothalamic arcuate nucleus Kisspeptin neurons after improving hyperglycemia and insulin resistance,thereby further improving the reproductive and endocrine metabolic dysfunction of PCOS.