Fish Oil Ameliorates High-fat Diet Induced Male Mouse Reproductive Dysfunction Via Modifying The Rhythmic Expression Of Testosterone Synthesis Related Genes

With the improvement of people's living standards,long-term intake of high fat poses a great challenge to human health.High fat is easy to induce obesity,fatty liver and other metabolic syndrome.Obesity and abnormal lipid metabolism can easily lead to reproductive dysfunction,especially the male reproductive dysfunction caused by longterm high fat diet is gradually getting more and more attention.Studies have shown that omega-3 polyunsaturated fatty acids(?-3PUFAs)can repaired HFD-induced male mouse reproductive dysfunction,that may be related to steroid synthesis in testicular tissue,but the specific role and mechanism remain unclear.Objective: The present study aims to investigate the protective effects of ?-3PUFAs against HFD-induced male mouse reproductive dysfunction and the explore the circadian regulation mechanisms.Methods: Male C57 bl mice were randomly divided into three groups: normal chow diet(control group,CON),high-fat diet(HFD group)and HFD supplemented with fish oil diet(FO group),20 mice each group.The mice were kept in a 12h/12 h light/dark circle animal house for 12 weeks,then continued feeding for one week after glucose tolerance was measured.Half of the animals were sacrificed at ZT0(light Start time point)and the other half were sacrificed at ZT12(night Start time point).Plasma was collected,testicular and other tissues were quickly removed.Plasma total cholesterol(TC)and plasma total triglyceride(TG)were determined using respective diagnostic kits.Plasma testosterone(T)and plasma estradiol(E2)were determined with the respective specific ELISA kit.The fixed liver tissue and testicular tissue were embedded in paraffin and sectioned thickness,stained with hematoxylin and eosin.Paraffin sections of testicular tissue were stained with the TUNEL technique.The expression of the testosterone biosynthesis related genes such as Lhr,Sf-1,Star,P450 scc,3?-Hsd,17?-Hsd and the biological Clock genes such as Clock,Bmal1 in testis were detected by RT-qPCR technique.The expression of testosterone synthesis key factors such as LHR,STAR,P450 SCC in testicular tissues were detected by western blot technique.Results: The body weight and the ratio of perinephric and epididymal fat weight to body weight were significantly higher in HFD group compared with CON group,fish oil rich only slightly reduced the HFD-induced obesity.Compared with the CON group,after HFD-treated,the plasma TC and TG levels were significantly increased,lipid accumulation in the liver cells,structural destruction of the testis(the lumens of seminiferous tubules were vacuolated,and the arrangement of spermatogenic cells were disturbed),the number of Leydig cells decreased and the number of apoptotic cells in testis were much more,sex hormone disorders.RT-qPCR result showed that fish oil significantly improved the expression of testosterone synthesis-related genes(such as Lhr,Sf-1,Star,P450 scc,3?-Hsd)induced by high fat diet.Western blot result showed that fish oil significantly improved the protein expression of LHR,STAR,P450 SCC.In addition,fish oil supplementation flattened the HFD-induced oscillations in circadian genes' expression(such as Bmal1,Clock,Cry1,Cry2,Ror?,Ppar?).Conclusion: Fish oil supplement prevented the HFD-induced male mouse reproduction dysfunction and modified the rhythmic expression of testosterone synthesis related genes.