Pyruvate Protects Trophozoites from Cysteine-Ascorbate Deprived Medium Induced Cytotoxicity.

, an anaerobic, amitochondriate protozoan parasite causes parasitic infection giardiasis in children and young adults. It produces pyruvate, a major metabolic product for its fermentative metabolism. The current study was undertaken to explore the effects of pyruvate as a physiological antioxidant during oxidative stress in by cysteine-ascorbate deprivation and further investigation upon the hypothesis that oxidative stress due to metabolism was the reason behind the cytotoxicity. We have estimated intracellular reactive oxygen species generation due to cysteine-ascorbate deprivation in . In the present study, we have examined the effects of extracellular addition of pyruvate, during oxidative stress generated from cysteine-ascorbate deprivation in culture media on DNA damage in . The intracellular pyruvate concentrations at several time points were measured in the trophozoites during stress. Trophozoites viability under cysteine-ascorbate deprived (CAD) medium in presence and absence of extracellular pyruvate has also been measured. The exogenous addition of a physiologically relevant concentration of pyruvate to trophozoites suspension was shown to attenuate the rate of ROS generation. We have demonstrated that protects itself from destructive consequences of ROS by maintaining the intracellular pyruvate concentration. Pyruvate recovers trophozoites from oxidative stress by decreasing the number of DNA breaks that might favor DNA repair.