Low altitude return ameliorates semen parameters after high altitude exposure

Background: A widely studied model of hypoxia is represented by high altitude (HA). Hence, HA hypoxia (HAH) is a challenge for people residing in or visiting high altitudes (Young and Reeves, 2002). Adaptation to HAH affects the homeostasis of several organs and the endocrine and metabolic functions. The aim of this study was to investigate the effect of HAH on the rat's semen and oxidative stress parameters. Methods: This experimental study was carried out at Abha city, Saudi Arabia, high altitude, 2,800 m above sea level; Jazan city, 43 m above sea level, low altitude. A total of 72 rats were used in this study—8 rats as control; groups 1, 2, and 3 each of 8 rats and group 4 of 40 rats were kept at high altitude for 8, 16, 24, and 32 days, respectively. From group 4, 32 rats were taken to low altitude to testify the reversibility of the semen parameters. Results: There were significant gradual decreases in the number and motility of the epididymal sperms in groups of rats exposed to HA during the first 3 weeks of HA exposure (HG1-HG3) with a maximum decreases to be seen in HG3 (-- 57.3 and -- 39.1%, respectively). However, the sperm count started to recover gradually on week 4 of HA exposure (HG4) and during all the periods of the reversal protocol achieved by returning the rats to the LA area (RG1-RG4). The maximum improvement in the sperm count and motility was seen in RG3 and RG4 which were not significantly different when compared with each other. The ANOVA test revealed that, in spite of the improvement in the sperm count which reach (109.3 ± 6.057 and 113.9 ± 8.967) in RG3 and RG4, their levels remained significantly low as those obtained in the control LA rats (129.2 ± 11.67). Conclusion: Exposure of rats to hypoxia resulted in a decrease in the sperm count and motility and an increase in the sperm morphological abnormalities. To conclude, the current study showed that the adverse effect of hypobaric hypoxia on semen parameters is transient and reversible