Figure 4: Histological examination of testicular injury in unilateral nephrectomized rats treated with cyclosporine, tacrolimus, or sirolimus. Male Sprague-Dawley rats were randomly divided into 5 experiment groups of eight animals each. All animals except for the control group were subjected to left unilateral nephrectomy. After recovery from surgery, animals received daily oral gavage of either drinking water or one of the drugs diluted in water for 8 weeks. The testes were harvested at the end of the study, and tissue sections were prepared for histological examination. (A) Morphological changes of seminiferous tubule architecture under light microscope in animals that received various treatments: a: control; b: unilateral nephrectomy (UN); c: UN plus cyclosporine; d: UN plus tacrolimus; e: UN plus sirolimus. Magnification, ×100 (upper panel); ×200 (middle panel); ×400 (lower panel). We examined 3 transversal sections of seminiferous tubules for each animal and one representative photo for each group was shown here. (B) Assessment of testicular injury by a histological scoring system as described in Table 1. Statistical significances between different treatments were determined by Mann-Whitney test using a SPSS program. CsA, cyclosporine; FK506, tacrolimus; Rapa, sirolimus. compared with UN group; compared with UN+FK506 group.