Testicular histomorphometry and the proliferative and apoptotic activities of the seminiferous epithelium in Syrian hamster during spontaneous recrudescence after exposure to short photoperiod.

Syrian hamsters are photoperiodic rodents in which reproduction, including testicular function, is stimulated by long photoperiod exposure and curtailed by exposure to a short photoperiod. The objectives of this study were to characterize the testis histomorphometrically and to determine the role of the proliferation and apoptosis phenomena in the recovery of the seminiferous epithelium during spontaneous recrudescence after exposure to short photoperiod. The study was performed using conventional light microscopy, proliferating cell nuclear antigen and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP in situ nick end labelling staining, image analysis software, and transmission electron microscopy in three recrudescence groups: initial recrudescence (IR), advanced recrudescence (AR) and total recrudescence (TR).