Effects of Camellia Sinensis Extract on Passive Avoidance Learning and Hippocampal Neurogenesis in Rats

摘要

We investigated the effects of a concentrate of green tea (extract of Camellia sinensis) on passive avoidance learning and hippocampal neurogenesis in male Wistar rats. Twenty-one male rats were divided into control, sham, and experimental groups. Rats of the control group were left intact, sham rats received infusions of 1.0 ml of distilled water for 8 weeks, while experimental rats received 1.0 ml of brewed green tea with a concentration of 0.04 g/ml. After eight weeks and behavioral testing, brain samples were taken, and 6-mu m-thick sections were prepared from the hippocampus and examined microscopically using hematoxylin+eosin staining. Results of the passive avoidance tests confirmed improved learning after green tea concentrate administration (P < 0.01). Treatment of the experimental group by the extract increased noticeably the density (number per test area) of neurons (intensity of neurogenesis) in the CA3 area and dentate gyrus of the hippocampus (P < 0.001).