Age-based immunomorphological analysis of rat testis in streptozotocin-induced diabetes mellitus

Diabetes mellitus (DM) has emerged as a public healthcare problem. Sustained hyperglycemia has been linked with many complications including impaired male fertility. The aim of the study: to evaluate the effect of STZ-induced diabetes mellitus on testicular immunomorphology both in the peripubertal period and adulthood of rats. Material and methods. Peripubertal male rats were injected with STZ (70 mg/kg), adult rats received 60 mg/kg. Immunohistochemical staining was performed to assess cell proliferation (Ki-67), apoptosis (caspase-3), expression of androgen receptors (AR), Wilms Tumor (WT1) protein. Also, the morphology of blood vessels was analyzed on the basis of CD34-immunoreactivity. Taking into consideration the small groups of animals, statistical analysis was made with the Mann-Whitney U test. Results. Fewer rows of proliferating spermatogonia were observed in the experimental animals (P < 0.05) of both age groups. Surprisingly, diabetes resulted in decreased caspase-3 expression (P < 0.05) except for the early period (2 weeks) in the peripubertal group, in which this trend was not observed. The same principles are true in terms of AR expression in seminiferous tubules. Hyperglycemia prevented immature testes from the complete development but thickens the walls of microvessels (P < 0.05). Also, the atrophy of spermatogenic epithelium and Sertoli cells was registered in most tubules of all the experimental groups (P < 0.05). Conclusion. the diabetic injury of testicular tissue is a long time process possessing characteristic feature in the peripubertal period, for example, the later development of AR deficiency. In addition, the high level of apoptosis is characteristic of an immature testis and so is the tendency of caspase-immunoreactivity to persist.