ABSTRACT
<p><b>OBJECTIVE</b>To determine the effects of cigarette smoking on the cyclogeny of spermatogenic cells in rats.</p><p><b>METHODS</b>Rat models of passive smoking were established using a self-made smoking device, and then allocated randomly into two passive smoking groups (A and B, n = 10) and two corresponding control groups (C and D, n = 10). Groups A and B were exposed to cigarette smoke for 8 weeks, followed by the sacrifice of the rats in Groups A and C. And the animals in Groups B and D were killed 48 days after the cessation of passive smoking. The spermatogenesis cycle of each group of rats was detected by flow cytometry, the levels of testosterone (T) and luteinizing hormone (LH) measured by radio-immunity method, and the testis histopathology analyzed by HE staining and transmission electron microscopy.</p><p><b>RESULTS</b>Compared with Group C, Group A showed a significant decrease in the number of spermatids, spermatozoa ([18.76 +/- 3.58]%) and primary spermatocytes ([5.71 +/- 1.18]%) (P < 0.01), but an obvious increase in the spermatogonias ([55.98 +/- 5.35]%, P < 0.01), with a markedly decreased proliferation index ( P < 0.01). The rats of Group A also exhibited pycnosis of spermatocytes, nucleus aberration of Leydig cells, expansion and degranulation of the endoplasmic reticulum, decreased Golgi apparatus, increased lysosomes and fat drops of Sertoli cells, as well as a reduction in the thickness of the wall and the layers of seminiferous tubules and the number of spermatogonia. The T and LH levels were significantly lower in Group A than in C (P < 0.01). After the cessation of passive smoking, a remarkable increase was observed in the percentage of spermatozoa and primary spermatocytes and the levels of serum T and LH in Group B, although the latter were still lower than those of Group D.</p><p><b>CONCLUSION</b>Smoking damages spermatogenic epithelia, Leydig cells and Sertoli cells, reduces the T and LH levels, and block the proliferation of spermatogenetic cells. These changes can be partially reversed after cessation of smoking.</p>