Spermatozoa HSP90b expression correlates with ROS generation and altered motility in response to methyl parathion treatment in vitro

Objectives: Widely used organophosphorus pesticides, methyl parathion (MePa), alter the reproductive functions in various animals and humans by induction of oxidative stress on augmented release of reactive oxygen species (ROS). MePa affects semen quality by inducing DNA damage through spermatogenic stages. Several heat shock proteins (HSPs) are expressed in response to environmental stressors particularly the redox-active ones for regulation of protein turnover. Since oxidative stress and sperm motility are implicated in MePa toxicity, studying the expression of HSP90b will unravel the mechanism behind its noxiousness. Material and Methods: Spermatozoa isolated from healthy donors were subjected to various concentrations of MePa (50, 250, 500, and 750 μM) for studying its effect on sperm motility, ROS generation, sperm chromatin integrity, and expression of stress responsive molecular chaperone HSP90b. Results: In vitro exposure of MePa at concentrations ≥500 μM results in a decline in sperm motility and an increased generation of ROS, DNA damage, and HSP90b expression. Conclusion: ROS-mediated modulation of HSP90b expression may affect the structural integrity of client proteins and oxidative injury to membrane lipid, along with DNA integrity resulting in declined sperm motility in response to MePa.