Effect of high altitude exposure on spermatogenesis and epididymal sperm count in male rats

Summary. The present study was designed to determine the effect of exposure to high altitude on spermatogenesis using transillumination technique and sperm count in male rats. In addition, the effect of oral intubation for intragastric administration of vehicle on testicular parameters in adult male rats in a schedule of 42 days was assessed. Male rats were exposed to Cerro de Pasco (Peru) at 4340 m for 3, 7, 14, 21, 28, 35 and 42 days resulting in a modification of the pattern of the seminiferous tubule stages. At day 3, stages I, IV‐V, VI, VII and IX‐XI were relatively shorter at high altitude than at sea level. At day 7, stages VIII, IX‐XI, XII and XIII‐XIV were reduced. At day 14, stages VII, VIII and IX‐XI were reduced. At day 21 and 28, stages VIII, XII and XIII‐XIV were significantly increased at high altitude. At day 35 an increase in stage XIII‐XIV was observed. At day 42, stages II‐III, IX‐XI and XII were significantly increased at high altitude. Epididymal sperm count was significantly reduced at day 7 of exposure to high altitude and maintained low levels with respect to sea level up to 42 days. In conclusion, high altitude exposure affects spermatogenesis, particularly onset of mitosis and spermiation. This in turn affects epididymal sperm count.