Study On The Correlation Between Testosterone Level And Lipid Metabolism And Atherosclerosis

Objectives1.Clinical research: To investigate the correlation between serum testosterone level and blood lipid,atherosclerosis and other risk factors for coronary heart disease in middle-aged and elderly men.2.Animal experiment: We used SD(sprague-dawley)male rats as the research objects to establish high-fat model,after the castration to add different concentrations of testosterone,the formation of different testosterone levels of rats and grouped to observe the effects of changes in testosterone levels on lipid metabolism,atherosclerosis.Methods1.We selected 226 middle-aged and elderly men of 40-79 years from our hospital inpatient and outpatient medical examination to collect general information.Height,weight,blood pressure,total testosterone(TT),total cholesterol(TC),triglyceride(TG),low-density lipoprotein cholesterol(LDL-C),high-density lipoprotein cholesterol(HDL-C),fasting plasma glucose(FPG)and fasting insulin(Fins)levels were measured.And calculate body mass index(BMI),atherosclerosis index(AI),insulin resistance index(HOMA-IR),and use color doppler ultrasonic diagnostic instrument to measure carotid artery intima-media thickness(CIMT).2.(1)High-fat diet was reared for 50 SD male rats aged 10 months(equivalent to middle-aged men)for 6 weeks,and of which 47 survived,high-fat rat model was ssuccessfully established.(2)According to the principle of randomization,6 rats were false-castrated as a control group and 41 rats were castrated.After 12 days of adaptive feeding,castrated rats survived 24 and randomly divided into 4 groups.All alive rats were divided into 5groups: high testosterone level group(HT group;n = 7,subcutaneous injection of 25mg/kg testosterone propionate every three days),medium testosterone level group(MT group;n = 6,subcutaneous injection of 5 mg/kg testosterone propionate every three days),low testosterone level group(LT group;n = 5,subcutaneous injection of 1 mg/kg testosterone propionate every three days),complete lack of testosterone group(CLT group;n = 6,subcutaneous injection of corresponding medical corn oil every three days),and normal control group(NC group;n = 6,subcutaneous injection of corresponding medical corn oil every three days).All groups were dosed for eight weeks.(3)Detection of peripheral blood testosterone,blood lipid levels,and calculated AS index(AI).(4)The rats were sacrificed and the livers were taken for HE and oil red staining,aortic and carotid artery for HE and Masson staining.The thickness and ratio of intima and medial membrane were measured.Results1.The correlation of serum testosterone levels and blood lipid and atherosclerosis in middle-aged and elderly men: testosterone was negatively correlated with TC,LDL-C,AI and CIMT(all P < 0.05),testosterone was positively correlated with HDL-C(P <0.05),and testosterone was no statistical correlation with TG(P>0.05).2.The correlation of serum testosterone levels and other occult coronary heart disease risk factors in middle-aged and elderly men: testosterone was negatively correlated with age,BMI(all P < 0.05),and testosterone was no statistical correlation with SBP,DBP,FPG,Fins and HOMA-IR(all P>0.05).3.Fatty rats model was successfully established: after high-fat diet for 6 weeks,serum TC,TG,LDL-C levels were higher than high-fat feeding before(all P < 0.01),while HDL-C level lower(P < 0.01).4.The effects of testosterone concentration changes on testosterone levels in middle-aged and elderly castrated male rats: the testosterone levels of the MT group and NC group were similar(P > 0.05),while the level of the HT group was higher than that of NC group(P < 0.05).The testosterone levels of CLT group and LT group were lower than that of NC group(all P < 0.05).5.The effects of testosterone concentration changes on blood lipids and AI in middle-aged and elderly castrated male rats: TC,LDL-C and AI levels of CLT group and LT group were higher than NC group(all P < 0.05);TC,LDL-C and AI levels of HT group and MT group are lower than CLT group(all P < 0.05).6.The effects of testosterone concentration changes on lining and film thickness of the aorta and the carotid artery in middle-aged and elderly castrated male rats: the ratio of intima and membrane of the aorta and the carotid artery of CLT group and LT group were greater than NC group(all P < 0.05);the ratio of intima and membrane of the aorta and the carotid artery of HT group and MTl group were less than CLT group(all P <0.05).7.The effects of testosterone concentration changes on liver pathology in middle-aged and elderly castrated male rats: HT group,NC group,MT group,LT group and CLT group of liver cell steatosis degree aggravating.8.The effects of testosterone concentration changes on the aorta and the carotid artery pathology in middle-aged and elderly castrated male rats: each groups' smooth muscle fiber composition of aorta and carotid artery wall was reducing,while collagen fiber thickening,but no significant differences between groups.Conclusions1.With age increasing,testosterone concentrations decreased gradually in middle-aged and elderly men.As the decline in testosterone levels,BMI,TC,LDL-C,AI and CIMT were gradually rised,and HDL-C was reduced.2.Testosterone can regulate peripheral blood cholesterol levels and liver lipid metabolism in middle-aged and elderly male rats;When testosterone leves decreased,TC and LDL-C increased.Testosterone deficiency can aggravate the degree of fatty degeneration of liver cells.3.Low testosterone levels increase development of atherosclerosis in middle-aged and elderly fatty castration rats,and appropriate testosterone supplementation can improve atherosclerosis in middle-aged and elderly fatty castration rats.