Effects of NO modulators and antioxidants on endocrine and cellular markers in rats under repetitive restraint stress.

The aim of the study was to evaluate the effects of NO modulators and antioxidant treatments on endocrine (plasma corticosterone), cellular (heat shock protein 70 [HSP-70] and nuclear factor κB [NF-κB]), and oxidative stress markers in repetitively stressed rats. Repetitive (restraint) stress (RS 1hr/day × 21 days) enhanced the levels of cellular and endocrine stress markers in the rat blood and altered pro-oxidant-antioxidant balance differentially in the control and test groups. Exposure to repetitive RS enhanced malondialdehyde (MDA) levels, lowered reduced glutathione (GSH), and superoxide dismutase (SOD) levels as well as nitric oxide (NOx) levels. NO precursor L-arginine and NO synthase inhibitors were found to differentially modulate stress-induced mechanism in altering NF-κB, HSP-70, and corticosterone levels. The antioxidant L-ascorbic acid (L-AA) significantly suppressed RS(×21)-induced elevation of NF-κB and HSP-70 levels, depicting protective effects, as also evidenced by reversal of elevated corticosterone levels. The results suggest that NO modulators and antioxidants differentially influence repetitive stress-induced changes in endocrine and cellular markers, and the complex interaction between NO and cellular markers like HSP70 and NF-κB plays a crucial modulatory role in this phenomenon.