MR 20. Cigarette smoke on sex hormones and seminal plasma biochemistry

Objective: (I) To investigate the impact of cigarette smoke on sex hormones (testosterone T, follicle stimulating hormone FSH, luteinizing hormone LH) of male rats; (II) To investigate the impact of cigarette smoke on seminal plasma biochemistry of male rats (fructose, zinc).

Methods: (I) 30 male SD rats of 8-week-old were randomly divided into smoking groups, smoking cessation group and control group, 10 in each group. (II) Blood samples were collected in each group before experiment for the determination of sex hormone. (III) Detection of sex hormone was performed in smoking group and 5 rats of control group 8 weeks later; seminal plasma fructose and zinc content was detected in fluid of seminal vesicle and prostate. HE staining of the left testis was performed. Smoking cessation group and another 5 rats of control group were detected by using the above method 12 weeks later. (IV) Content of serum testosterone, follicle stimulating hormone, luteinizing hormone was determinated by radioimmunoassay; UV spectrophotometric method was used to detect the fructose of seminal plasma; and zinc level in seminal plasma was detected by colorimetric method.

Results: (I) Detection results of sex hormones: There were no significant differences among the pre-experimental levels of T, FSH, LH of the three groups. The contents of T, FSH, LH in smoking group were all lower than those of pre-experiment, the differences were of statistical significance (P<0.05); the contents of T, FSH, LH in smoking group were all lower than those of control group at the 8^th week, the differences were of statistical significance (P<0.05); the contents of T, FSH, LH in smoking group were all lower than those of smoking cessation group before experiment, the differences were of no statistical significance (P<0.05); the levels of T, FSH, LH in smoking group were all lower than those of control group at the 12^th week, the differences were of no statistical significance (P<0.05). The levels of T, FSH, LH of control group before experiment, at the 8^th week and at the 12^th week were of no statistically significant differences. (II) Results of seminal plasma biochemistry test: Seminal plasma fructose and zinc contents of smoking group was decreased compared with those of control group at the 8^th week with statistically significant differences (P<0.05); Seminal plasma fructose and zinc contents of smoking group was decreased compared with those of control group at the 12^th week, the difference of seminal plasma between the two groups was of statistical significance (P<0.05), and the difference of zinc content between the two groups was not statistically significant (P>0.05); the differences of seminal plasma fructose and zinc contents between group at the 8^th week and group at the 12^th week were not statistically significant (P>0.05); (III) Results of seminal plasma biochemistry test: seminal plasma fructose and zinc contents of smoking group was decreased compared with those of control group at the 8^th week with statistically significant differences (P<0.05); seminal plasma fructose and zinc contents of smoking group was decreased compared with those of control group at the 12^th week, the difference of seminal plasma fructose between the two groups was of statistical significance (P<0.05), and the difference of zinc content between the two groups was not statistically significant (P>0.05); the differences of seminal plasma fructose and zinc contents between control group at the 8^th week and the 12^th week were not statistically significant (P>0.05); (IV) Results of testicular HE staining: the basement membrane of seminiferous epithelium in testicular tissue of control group the 8^th week and the 12^th week was intact, spermatogenic cells were highly ordered with clear layers. The basement membrane of seminiferous epithelium in smoking cessation group got thinner, spermatogenic cells were less compare with those of control group, they also showed discontinuity, and layers became thinner, tubular gap was broadened with less stromal cells. The basement membrane of seminiferous epithelium in smoking group was ruptured and dissoluted, spermatogenic cells were less, smaller and in disorder, cell space became larger with interstitial edema, stromal cells were further decreased.

Conclusions: (I) Cigarette smoke leads to decrease of serum testosterone, follicle stimulating hormone and luteinizing hormone in male rats; which may interfere the function of hypothalamic-pituitary-testicular gonadal axis, and may affect spermatogenesis; (II) Cigarette smoke may lead to the decrease of seminal plasma fructose and zinc and have effect on the quality and density of semen; (III) This study can provide some evidences for the role of cigarette smoke in the etiological diagnosis of male infertility.