| OBJECTIVE: To clear the correlations between male semen quality or sex hormone levels and exposure levels in soy isoflavones,we investigated the prevalence of soy isoflavones in adult males by epidemiological investigation and laboratory testing of normal adult males in Chongqing.The effects of different isoflavones metabolites on sex hormone levels and semen quality were investigated by animal experiments.Our aim is to provide a reference for the adverse effects of soybean isoflavones on male reproductive health.METHODS: 1.Population study: Our study was for adult men recruited in Fengdu County,Chongqing,in 2015.We collected the basic information of the subjects through the compound questionnaire and collected the blood,urine and semen samples of the volunteers.The levels of SIF metabolites in the urine were analyzed by high performance liquid chromatography(HPLC).The semen parameters were analyzed by computer-aided sperm analysis(CASA)The sperm chromatin structure assay(SCSA)was used to detect the DNA damage of sperm nucleus.Quantitative long polymerase chain reaction and real-time fluorescence quantitative PCR were used to measure mitochondrial DNA(mtDNA)copy number and integrity in spermatozoa.The levels of serum sex hormones were measured by chemiluminescence assay.SPSS16.0 software was used to analyze the association between SIF urinary metabolite levels and semen quality and serum sex hormone levels.The inclusion criteria for the study subjects are as follows:(1)The number of days of abstinence is 2 to 7days;(2)The subjects were aged 18 to 55 years old;(3)Subjects had no history of urinary tract infection,history of epididymitis,history of testicular injury,history of varicoceletreatment,and history of testicular descent;(4)Subjects did not have Adam’s apple,pubic hair,breast dysplasia,penile abnormalities,testicular injury,epididymal inflammation,varicocele,cryptorchidism;(5)No semen parameters studied were five missing persons;(6)The concentration of creatinine(CR)in the study was 0.3 ~ 3g / L.We finally included 161 subjects as subjects.2.Animal experiment: 60 male rats aged 4 weeks(adolescent)were randomly divided into 6 groups: normal control group,genistein 5mg / kg,genistein 50 mg / kg,genistein 500 mg/ kg,genistein 2000 mg / kg,diethylstilbestrol 0.1 mg / kg,10 rats in each group for 29 days.We randomly selected 5 rats from each group at the 8th week old to observe the changes of organ coefficient,testicular tissue structure and serum sex hormone level.The remaining 30 were sacrificed after their adult age(11 weeks old).We observed the effect of adolescent ingestion of GEN on its adult organ coefficient,testicular tissue structure,sex hormone levels and semen quality.The expression level of beta estrogen receptor(ERβ)in testes of adult rats was detected by Western blot(WB).RESULTS: 1.Population study: Univariate results showed that semen volume and sperm density showed a decreasing trend(p = 0.044 and 0.018)as the total exposure level increased,and the semen volume increased with the increase of equol concentration(p = 0.034).After multiple potential regression factors(age,body mass index,abstinence days,smoking status,drinking status)were corrected by multiple linear regression methods,these associations disappeared.At the level of sex hormones,serum levels of Luteinizing hormone decreased with the increase of genistein exposure(p = 0.019).With the increase of glycitein concentration,serum testosterone level decreased(p < 0.001).With the increase of dihydrogen daidzein yuan concentration,serum progesterone decreased(p = 0.021).After correcting the confounding factors,these associations still exist.In addition,multivariate analysis revealed acorrelation between sperm DNA damage and semen quality.2.Animal experiments: Rats in the adolescent intake of genistein,the recent and adult groups of body weight and organ coefficient was no significant difference.After adulthood,the sperm density and sperm count of the 2000 mg / kg dose group decreased(p <0.05).The results of HE staining showed that the diameter of seminiferous tubules in the testes of the rats at the end of puberty was shorter and the cells in the lumens were sparse and arranged in the 2000 mg / kg genistein dose group.After adulthood,the spermatozoa of spermatogenic tubules in the 2000 mg / kg dose group decreased,and the remaining dose group did not change significantly.At the level of sex hormones,serum estradiol levels in the 5 mg / kg and 50 mg / kg dose group were significantly lower than those in the normal control group(p<0.05).50 mg / kg dose group of serum follicle-stimulating hormone,testosterone were transiently increased.After adulthood,these differences disappear.There was no significant difference in E2 and testosterone concentration between adolescent and control group(p <0.05).WB results showed that the expression of ERβ in estrogen receptor testis of adolescent rats did not change significantly,but the expression level of ERβ in testes of adult rats increased with the increase of genistein dose.CONCLUSION: The results showed that normal dietary intake of soy isoflavones had no significant effect on male semen quality,but had a significant effect on serum sex hormone levels,for example,it reduced serum testosterone,luteinizing hormone,progesterone.The results of animal experiments showed that a certain level of genistein(genistein 5mg / kg dose group,50 mg / kg dose group,500 mg / kg dose group)had no significant adverse effect on male reproductive health,but when the dose of genistein reached 2000 mg / kg,serum testosterone levels,sperm density and total sperm count decreased and sperm concentration increased. |
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