Tobacco smoke exposure induces irreversible alteration of testicular function in prepubertal rats.

BACKGROUND

Smoking is a serious public health problem and an important risk factor of many diseases. The present study evaluated whether or not the influence of prolonged tobacco smoke (TS) exposure on spermatic indices and reproductive hormones would be reversible in young and adult rats.

METHODS

Prepubertal and adult rats were grouped into five (I, II, III, IV, and V) separately (n=5/group) and exposed to TS at target concentrations of 0, 0.5, 1.0, 0.5, and 1.0 mg nicotine/day, respectively for 30 days using the whole body exposure inhalation method. Groups I, II, and III were sacrificed 24 h after TS exposure, while groups IV and V were allowed to recover for 30 days before they were sacrificed.

RESULTS

Sperm count and motility were significantly (p<0.05) reduced in exposed prepubertal and adult rats. Additionally, sperm morphology was unaltered, testosterone was reduced, while luteinizing hormone (LH) and follicle stimulating hormone (FSH) were elevated compared to the non-TS exposed control group. The reductions in sperm count and motility were reversed only in adult recovery rats. LH and FSH elevations were reversed in all recovery animals, but testosterone concentrations remained lower than control. Furthermore, malondialdehyde levels in testes of exposed rats were significantly increased. This was reversed only in adult recovery rats that received 0.5 mg nicotine. Testicular levels of catalase, reduced glutathione, and superoxide dismutase were unaltered, except in prepubertal rats wherein catalase was decreased in both treated and recovery groups.

CONCLUSIONS

The TS exposure alters sperm characteristics reversibly in adult, but irreversibly in prepubertal rats, which is attributable to elevation of oxidative stress.