| Object: In this experiment,high-fat diet-induced obesity model was established through feeding high-fat diet in C57BL/6J male mice.We tried to explore the role of kisspeptin/GPR54 on testoeterone decline in the high-fat diet-induced obesity mice,which may provide a new theoretical basis for male reproductive damage and mechanism caused by obesity.Material: Forty-eight male C57 BL / 6J mice(4-5weeks)were randomly devided into the control group(n=12 normal diet)and obesity model group(n=36 high-fat diet)and fed for 19 weeks.After 19 weeks,the mice in obesity model group were divided into diet-induced obesity group(n=12)and diet-induced obesity resistance group according to the sequence of weight gain.All mice were sacrificed and the epididymis rapidly separated for sperm count and activity;Mouse epididymal and retroperitoneal fat were isolated and weighed;Serum levels of leptin,estrogen and testosterone were detected by ELISA assay;Pathological changes of leydig cells were observed by electron microscopy;Total RNA and protein were extracted from hypothalamus,and Kiss-1,GPR54 and Gn RH m RNA levels were measured by q RT-PCR;The protein level of Kisspeptin were detected by Western blot;the protein levels of GPR54 and Gn RH were determined by immunohistochemistry.Result:1.Body weight changes among DIO,DIO-R and control miceThere was no significant difference of body weight among the three groups in the first week(P>0.05).From the second week of experiment,the body weight in DIO group was significantly higher than that in control group(P<0.05).At the end of the experiment,the body weight in DIO group was significantly higher than that in DIO-R group and control group(P<0.05).There was no significant difference of body weight between DIO-R group and control group(P>0.05).2.Epididymal and Retroperitoneal fat among DIO,DIO-R and control miceA significant increase in epididymal fat,epididymal index,retroperitoneal fat,and retroperitoneal index was observed in DIO and DIO-R group compared with control group(P<0.05).However,there was no significant difference between DIO mice and DIO-R mice(P>0.05).3.Comparison of sperm count and activity among DIO,DIO-R and control miceThere was no significant difference of sperm count in the DIO,DIO-R and control mice(P>0.05).The sperm activity of the DIO and DIO-R mice were lower than that of the control group.However,only the sperm activity of the DIO mice were significant lower than that of the control mice(P<0.05).4.The levels of leptin,estradiol and testosterone among DIO,DIO-R and control miceCompared with the control mice,a significant increase in the leptin and estradiol levels was observed in the DIO and DIO-R mice(P<0.05).Compared with the control mice,a decrease in the testosterone level was observed in the DIO and DIO-R mice.However,only the level of testosterone significantly decreased in DIO mice compared with the control mice(P<0.05).5.Electron microscopic results of testicular tissue among DIO,DIO-R and control miceCompared with control group,a large number of lipid droplets,irregular karyotype and heterochromatin margination were found in leydig cells of DIO and DIO-R group.6.The Expression of Kisspeptin Protein in the Hypothalamus among DIO,DIO-R and control miceCompared with the control mice,a significant decrease of Kisspeptin protein expression in hypothalamus was observed in the DIO and DIO-R mice(P<0.05).However,there was no significent difference between DIO-R and control mice(P>0.05).7.The Expression of GPR54 Protein in the Hypothalamus among DIO,DIO-R and control miceCompared with the control mice,a significant decrease of GPR54 protein expression in hypothalamus was observed in the DIO and DIO-R mice(P<0.05).However,there was no significent difference between DIO-R and control mice(P>0.05).8.The Expression of Gn RH Protein in the Hypothalamus among DIO,DIO-R and control miceCompared with the control mice,a significant decrease of Gn RH protein expression in hypothalamus was observed in the DIO and DIO-R mice(P<0.05).However,there was no significent difference between DIO-R and control mice(P>0.05).9.The Expression of Kiss-1,GPR54,Gn RH m RNA in the Hypothalamus among DIO,DIO-R and control miceCompared with the control mice,a significant decrease of Kiss-1,GPR54,Gn RH m RNA level in hypothalamus was observed in the DIO and DIO-R mice(P<0.05).However,there was no significent difference between DIO-R and control mice(P>0.05).Conclusion: Decreased sperm motility and testosterone levels were found in high-fat diet-induced obese male mice.A line of evidence suggests that down-regulation of Gn RH in the murine hypothalamus caused by decreased expression of kisspeptin/GPR54 may contribute to decreased sperm motility and testosterone level in obese male mice. |
