Grape seed proanthocyanidin extract suppresses oxidative stress in the rat pancreas of type-1 diabetes.

AIM: This study aimed to elucidate the effects of grape seed proanthocyanidin extract (GSPE) on oxidative stress (OS), antioxidant enzymes, free radicals and cytokines in the pancreas of T1DM rats. METHODS: Two-month-old Wistar rats were assigned to the control (CON), CON + GSPE (CON + PA), diabetics (STZ, 60 mg/kg b.w.), diabetes + GSPE (STZ + PA), diabetes + insulin (STZ + INS, 3 U/day) and diabetics + GSPE and INS (STZ + INS + PA) groups. GSPE (75 mg/kg b.w.) was administered daily either alone or with INS for 8 weeks. RESULTS: Glutathione was lowest in diabetics while it increased in the STZ + INS + PA (p < .001) group, similar to catalase activity (p < .05). Hydrogen peroxide, superoxide and lipid peroxidation increased with iNOS, TNF-α and IL-1ß in the diabetic pancreases, while GSPE decreased (p < .001). Further, reduced ß-cells/islet number was improved in diabetics (p < .001) with treatment. CONCLUSION: This study suggests that GSPE with INS is effective in minimising OS and pancreatic degeneration in T1DM rats.

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 400mg GSPE/kg body weight. Swimming training lasted for 2h/day and for 14weeks. 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.

Grape Seed Proanthocyanidin and Swimming Exercise Protects Against Cognitive Decline: A Study on M1 Acetylcholine Receptors in Aging Male Rat Brain.

Decline in cognition is one of the earliest signs of normal brain aging. Several dietary and non-pharmacological approaches have been tested to slow down this process. The aim of the present study was to assess the influence of grape seed proanthocyanidin extract (GSPE) either individually or in combination with swimming training on acetylcholine esterase activity (AChE) and m1 acetylcholine receptor (m1AChR) on the extent of cognitive decline with aging. The experimental protocol included the oral administration of GSPE (400 mg/kg body weight) for 14 weeks to 4 (adult) and 18-month-old (middle-aged) male Wistar rats along with swimming training. They were subjected to behavioral testing followed by biochemical and immunohistochemical analysis. The results demonstrated that GSPE supplementation and swimming training either individually or in combination had an improvement on acquisition and working memory with reduced AChE activity in the medial prefrontal cortex (mPFC) and hippocampus (HC). Immunohistochemical and qRT-PCR evaluation showed an increase in m1AChR protein and mRNA in the CA1 region of HC and also mPFC upon swimming training with GSPE treatment. These beneficial and synergistic effects of GSPE and swimming training are suggestive as interventions in modulating the cognitive function, with GSPE alone being more suitable for middle-aged individuals.