Cigarette smoking induces apoptosis in rat testis.

In a previous studywe demonstrated the deleterious effect of cigarette smoke on spermatogenesis in the testis of peripubertal Sprague-Dawley rats. In this study we investigated the development of apoptosis as a possible contributing factor to the pathogenic mechanism underlying these effects. Peripubertal rats were exposed to cigarette smoke with the Walton Horizontal Smoking Machine. Similarly, age-matched control rats were exposed to room air with the smoking machine. Rats from both groups were sacrificed after 45 days of treatment and the testes were removed. Testes were stained utilizing the terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) staining technique. DNA fragmentation was further evaluated using gelectrophoresis. There was a significant increase in the incidence of apoptosis in the treated group compared to the control group as demonstrated by the larger amount of tubules containing > or = 3apoptotic bodies in the smoke-exposed group, that is, 36% versus 14% in the control group (p < 0.05). Agarose gel electrophoresis demonstrated the DNA ladder in the treated group but not in the control animals. In conclusion, chronic cigarette smoke induces apoptosis in the rat testis. Apoptosis may be one of the pathogenic mechanisms responsible for defective spermatogenesis in the rat following chronic cigarette smoking.