Antioxidant action of grape seed polyphenols and aerobic exercise in improving neuronal number in the hippocampus is associated with decrease in lipid peroxidation and hydrogen peroxide in adult and middle-aged rats

The present study explored the effects of swimming training and grape seed proanthocyanidin extract (GSPE) on neuronal survival in the hippocampus (HC) of middle-aged rats along with oxidative stress (OS) parameters. Further, the bioavailability of the GSPE, catechin, epicatechin and gallic acid were measured in the HC and plasma. Male Wistar rats were grouped into: sedentary control, SE-C; swimming trained, SW-T; SE-C, supplemented sedentary, SE-C(PA) and swimming trainees, SW-T(PA). The supplement was a daily dose of 400 mg GSPE/kg body weight. Swimming training lasted for 2 h/day and for 14 weeks. Glutathione level was increased in response to single and combined interventions in the middle-aged rats. Adult trainees showed increased glutathione peroxidase activity unlike middle-aged wherein increase was seen in SE-C(PA) alone. Lowered catalase activity with age in the HC increased in response to the combined interventions although single interventions were also effective. HC from both ages showed decrease in lipid peroxidation and hydrogen peroxide levels in response to the interventions. GSPE constituents were seen in the HC of swimming trained middle-aged and adult rats. The study suggests that combined intervention is effective in decreasing LPO and H2O2 generation in the HC. Further, the neuronal numbers and planimetric volumes of CA1 pyramidal layer was significantly reduced in middle-aged rats compared to adults. Interestingly, both interventions enhanced the numbers and volumes in adult and middle-aged rats. Thus, age-associated decrease in CA1 neurons could be restored by both the interventions. The results of the present study will help in developing effective therapies for age-associated degenerative changes and cognitive deficits.