Effects of Smoking on Plasma Testosterone Level and Erectile Function in Rats

Abstract

There have been several conflicting reports of the effects of smoking on plasma testosterone levels and erectile function in clinical and animal studies. This study was conducted to determine the actual effects of smoking on plasma testosterone levels and erectile function in rat-smoking models. For the exposure to cigarette smoke, the rats in a cage had a constant influx of smoke using a specially constructed device. Twenty-four Sprague Dawley (SD) rats for the acute cigarette exposure were allocated randomly into two groups: an experimental group and a control group. Thirty-six SD rats for the chronic cigarette smoke exposure were randomly divided into three groups: a control group and two experimental groups. After exposure to smoking, the rats were subjected to electrical field stimulation of the cavernosal nerve to assess the erectile function, and blood was collected to measure the levels of plasma thiocyanate, testosterone, luteinizing hormone, and follicle-stimulating hormone. The histological changes of testes and corpora cavernosum (CC) were examined. In the smoking groups, the thiocyanate levels were significantly higher than in the control group. Also, the mean arterial pressure (MAP) was significantly higher in the smoking groups, but the corpora cavernosal filling rate and maximal intracavernosal pressure/MAP were significantly lower than in the control group. The testosterone levels of experimental groups were significantly lower than those of control group, and the testosterone and thiocyanate levels were significantly correlated with erectile function components in chronic smoking groups. There was no significant histological change in the testes; however, in the CC, there was an increase in collagen fibers and decrease in smooth muscle and sinusoidal space in chronic smoking groups. The results suggest that both the vasoconstrictor effects of smoking and the decrease in testosterone levels after chronic smoking had some effects on erectile function in rats.