Fig. 1. Cross sections of seminiferous tubules of stallions treated with the multiple low-dose (2.5 mg/kg bw/week) IV busulfan injection.

The three different patterns of spermatogenesis were classified as: (A and B) normal, (C and D) Sertoli cell only, and (E and F) abnormal spermatogenesis, using H&E staining. In normal spermatogenesis the seminiferous tubules were filled (A and B). In Sertoli cell only tubules, the round seminiferous tubules were hollowed without germ cells, but Sertoli cells were attached adjacent to the basement membrane (C and D). In the abnormal spermatogenesis tubules, the germ cells were fragmented (E and F). Bar = 200 µM. H&E, hematoxylin and eosin.