Abstract
Background: Stress and increase in free radicals levels are known to alter cognition, learning, memory, and emotional responses. There is a marked impairment of hippocampus-dependent memory and suppression of long-term potentiation in the CA1 region of the hippocampus during stress.

Aim and Objective: The aim of this study is to evaluate the hypothesized neuroprotective effect of oral antioxidants and piracetam in chronic restraint stress-induced rats.

Materials and Methods: Healthy Wistar rats were divided into 5 groups (n = 6) each. Control group received neither stress nor oral antioxidant. Stress group received chronic restraint stress for 6 h per day for 21 days. Three experimental groups were administered vitamin C (100 mg/kg), beta-carotene (7 mg/kg), and caffeine (8 mg/kg), respectively. Evaluation parameters were measurement of serum nerve growth factor (NGF) using ELISA method. The oxidative stress markers, glutathione peroxidase (GPx), glutathione reductase, and malondialdehyde were measured. Histological analysis of CA1 region of the hippocampus was done to evaluate the structural changes of pyramidal neurons.

Results: Vitamin C caused statistically significant (P < 0.001) increase in serum NGF. The results revealed that vitamin C caused statistically significant (P < 0.05) increase in antioxidant enzymes GPx, glutathione reductase. Vitamin C caused increase in neuronal cell size and volume in CA1 pyramidal layer of hippocampus.

Conclusion: The findings of study are suggestive of neuroprotection, offered by administration of vitamin C compared to other antioxidants against chronic restraint stress-induced rats. These naturally available dietary vitamins might serve as an adjuvant therapy to avoid progression of brain damage during stress.

Key words: Nerve Growth Factor; Vitamin C; Beta-Carotene; Caffeine; Pyramidal Neurons