Chronic green tea consumption prevents age-related changes in rat hippocampal formation

The hippocampal formation undergoes considerable structural and functional modifications during aging and oxidative stress emerges as a key player in the process. In the present study, we investigated whether prolonged consumption of green tea (GT), which contains large amounts of polyphenols, could interfere with age-related changes in this brain region using biochemical, morphological and behavioral approaches. Ten male Wistar rats aged 19 months were fed with GT since 12 months of age and results compared to those obtained from controls aged 19 months (C-19M). At 12 months of age, another group of rats was evaluated to provide baseline data. Oxidative stress markers (protein carbonyls and malondialdehyde) were quantified in hippocampal homogenates and stereological methods were applied to estimate the deposition of lipofuscin in hippocampal CA3 pyramidal neurons. Morris water maze was used to assess spatial learning and memory. Aging increased oxidative markers and lipofuscin accumulation and was associated with impaired memory acquisition. However, GT treatment protected proteins and lipids against oxidation and prevented the increase of lipofuscin deposition compared to age-matched controls. Furthermore, the spatial learning abilities of GT-treated rats were significantly improved when compared to those from C-19M group. Taken together, these findings confirm the neuroprotective ability of GT in the hippocampal formation probably due to the reduction of oxidative stress-related damage observed during aging.