Reduced antioxidant status for prolonged period due to repeated stress exposure in rat

Abstract

The objective of the study was to find out whether or not exposure to a stressor after an initial stressful experience augments stress response. Antioxidant status was determined by measuring changes in the activities of the hepatic free radical scavenging enzymes viz, superoxide dismutase (SOD), glutathione-S-transferase (GST), glucose-6-phosphate-dehydrogenase (G6PDH) and catalase (CAT) and levels of hepatic malondialdehyde (MDA) following exposure to 1 h restraint (RS) and after a gap of 4 h to forced swimming exercise (FS) in rats. The activities of hepatic CAT, SOD, G6PDH and GST were significantly reduced 2 h after RS compared to controls and 4 h after FS the activities of CAT and G6PDH remained at lower levels i.e. they were similar to those found after RS , whereas SOD and GST showed further significant decrease compared to those found after RS. On the other hand the MDA levels, indicative of lipid peroxidation were significantly increased after RS and showed further significant increase after FS. The results reveal that after initial stressful experience, the stress response is augmented due to exposure to another stressor whereas the system does not get habituated to stress exposure.

Keywords

• CAT
• G6PDH
• GPx
• GST
• MDA
• oxidative stress
• SOD
• stress