RESUMO
<p><b>OBJECTIVE</b>To study the ultrastructural changes of the rat convoluted seminiferous tubule after alcohol consumption.</p><p><b>METHODS</b>Forty-eight Wistar mature male rats were divided into two groups randomly: control group (A) and experimental one (B). 6 ml/(kg x d) of 50 degrees alcohol was perfused through the gastric tube for 39 days in Group B; and 6 ml/(kg x d) of normal saline was supplemented in Group A. The ultrastructure of the rat convoluted seminiferous tubule was observed by transmission electron microscope at day 14, 27 and 40.</p><p><b>RESULTS</b>In Group A, the pykno-basement membrane was unstriated and uniform, Sertoli cells showed cytoplasmic profusion, with big nucleus, well-distributed nucleoplasm, distinct nucleolus, more mitochondria and plain hierarchical tight-junction. And the ultrastructure of the rat convoluted seminiferous tubule in Group B began to change at the end of the first spermatogenic cycle (D 14) and changed more and more evidently with the ethanol administration, mainly as follows: (1) more lysosomes and vacuolisation found in Sertoli cells, and organelles decreased and blurry; (2) more and bigger vacuoles among the spermatogonia, Sertoli cells and basement membrane; (3) obvious apoptosis of spermatogonia and apoptotic bodies aggregated near the membrane; (4) more cytoplasm and vacuolisation in the sperm of the convoluted seminiferous tubule, and disarranged, deleted or clustered mitochondria in the sperm tail; (5) blurry and rigid tight-junction; (6) thickened, wrinkled or broken basement membrane and under-basement</p><p><b>CONCLUSION</b>Alcohol can cause ultrastructural changes of the basement membrane, tight-junction and Sertoli cells of the membrane. rat convoluted seminiferous tubule and apoptosis of spermatogonia.</p>