Ultrastructural studies of spermatozoa and the epithelial lining of the epididymis and vas deferens in rats treated with gossypol.

This study was undertaken to determine the effects at early time intervals of gossypol on sperm motility and on the ultrastructure of rat epididymal and vasal sperm and epididymal and vasal epithelium. Rats were treated by gavage with 20 or 30 mg/kg/day of gossypol for 7 weeks; control animals were unfed or received the vehicle alone. The results confirm and extend earlier observations demonstrating that epididymal sperm of gossypol-treated rats exhibit distinct ultrastructural changes under the experimental conditions employed. The severity and frequency of the degenerative changes appear to increase with dose and duration of treatment. Striking ultrastructural defects can be seen as early as 3 weeks after 20 mg/kg/day of gossypol. By the fifth week of either 20 or 30 mg/kg/day of gossypol, significant damage to virtually all sperm flagella is observed throughout the epididymal duct of all treated rats. The initial and predominant defect is degeneration of the midpiece mitochondria but additional flagellar defects are described in detail. Not surprisingly, caudal spermatozoa are totally immotile by the fifth week. The ultrastructure of the epididymal and vasal epithelium is not affected by gossypol.