Oligoasthenoteratozoospermia and Necrozoospermia: A Study of Sperm Na⁺, K⁺-ATPase α4 and Plasma Membrane Ca²⁺-ATPase 4 Regulation

The oligoasthenoteratozoospermia (OAT) and necrozoospermia are the extreme sperm abnormalities in male infertility. These sperm abnormalities may be related to the imbalance of ion transport which mediated by the ion-transporting P-type ATPases, such as Na⁺, K⁺-ATPase and Ca²⁺-ATPase. Until now, there is limited data about the activity of Na⁺, K⁺-ATPase and Ca²⁺-ATPase in sperms in the OAT and necrozoospermia samples. Therefore, this study investigated the activity of Na⁺, K⁺-ATPase and Ca²⁺-ATPase and the expression of Na⁺, K⁺-ATPase α4 and PMCA4 isoforms in both sperm abnormalities. Eighteen semen samples from OAT and necrozoospermia infertile couples were examined in this study. Semen analysis was performed based on WHO 2010, while the enzyme activity was calculated by the released inorganic phosphate. The expression of Na⁺, K⁺-ATPase α4 and PMCA4 isoform was defined by Western immunoblotting, whereas the localization of the proteins was analyzed by immunocytochemistry. This study showed that the activity of Na⁺, K⁺-ATPase and the expression of Na⁺, K⁺-ATPase α4 isoforms in OAT and necrozoospermia group were lower than the normozoospermia group (1.452±0.549 versus 0.559±0.160 versus 1.962±0.56 µmol Pi/mg protein/h, respectively; p>0.05). In addition, the activity of Ca²⁺-ATPase and the expression of PMCA4 of OAT and necrozoospermia group were also lower compared to the normozoospermia group (2.028±0.524 versus 0.928±0.248 versus 2.657±1.329 µmol Pi/mg protein/h, respectively; p>0.05). For both ATPases, the necrozoospermia group showed lower values compared to the OAT group. The disruption in ATPase and isoform expression in OAT and necrozoospermia may be responsible for sperm structure and functional damage.