Photomicrographs of seminiferous tubules of rats from C-30 (A), C-60 (B), T-30 (C) and T-60 (D) groups stained by H.E. (A and B) In the seminiferous tubules with normal aspect, the germ cells are organized in concentric layers and the tubular lumen is empty (A, asterisks); (B) The Sertoli cell nuclei (arrows) are positioned adjacent to the well defined peritubular tissue in which peritubular cells are observed (arrowheads). In T-30 (C) and T-60 (D), the altered seminiferous tubules show irregular shape, epithelial disorganization and detached germ cells filling the tubular lumen (asterisks). In some atrophied seminiferous tubules, loss of germ cells is observed (arrows). Figs. 1A, 1C and 1D: ×110; Figs. 1B: ×330.