Abstract

Ageing is associated with oxidative stress-related biochemical alterations that cause progressive neuronal damage in the brain leading to deleterious morphological and behavioural modifications. On the other hand, catechins present in beverages such as green tea (GT) display strong antioxidant and anti-inflammatory properties. In Golgi-impregnated dentate granule cells of old rats we have analysed the structure of dendritic trees and the number of dendritic spines after a prolonged GT treatment. Our results demonstrate that the chronic consumption of GT during ageing protected neurons of the hippocampal formation, an important region involved in cognition, from age-associated detrimental morphological changes in dendritic trees, supporting the involvement of the GT catechins on such protection.

INTRODUCTION

Ageing is related to the inevitable and progressive accumulation of deleterious morphological and physiological events that occur as a result of time in animals. The initiation of the changes associated with senescence was linked to the relative excess of active free radicals, normally produced in the organisms (1). According to the radical oxidative/stress theory, as proposed initially by Denham Harman, aerobic organisms developed antioxidant defences to protect cells from the pro-oxidant damage (1-4). The balance between antioxidants and pro-oxidants can be lost in the presence of elevated and sustained production of active free radicals or decreased levels of antioxidant defences resulting in oxidative stress, as occurs during ageing (1, 3, 4).
The central nervous system (CNS) is one of the most vulnerable organic systems because the brain uptakes 20% of the total oxygen consumed, has a low quantity of antioxidant defences and neurogenesis is scarce (5). In addition, the presence of abundant polyunsaturated acids shifts the balance between antioxidants and pro-oxidants during ageing in brain (1) and as consequence oxidative stres ...