Hypobaric hypoxia causes impairment of spermatogenesis in developing rats at pre-puberty.

The effect of hypoxia on the spermatogenesis of male Wistar rats (n = 32) at pre-puberty was studied using a hypobaric chamber simulating an altitude of 5,000 metres above sea level. Persistent hypoxic exposure with brief interruption for 3 weeks caused significant decreases in body and testis weights and testosterone level compared to the normobaric controls. Histologically, spermatogenic development was arrested; arrays of spermatids were misshaped; numbers of spermatogonia, Sertoli and Leydig cells were reduced; and apoptotic spermatocytes were increased substantially in the germinal epithelium of testis in the hypoxic-exposed group. These hormonal and histopathological changes did not improve remarkably after 3 weeks of normobaric conditions. There was a significant decrease in sperm production when the rats in the hypoxia/oxygen-resuming group were examined at 63 days of post-natal age. Exposing rats to hypoxic conditions at pre-puberty induced damages on spermatogenesis, which could affect sperm production after sex mature.