[Effect of green tea polyphenols on behavioral performances in psychological stress rats]

This study was conducted to explore the effects of green tea polyphenols modulation on changes of behavioral performances in psychological stress rats.

The animal model of psychological stress was developed by restraint stress for 3 weeks. Wistar rats were randomly assigned to five groups as follows: control group (CT), stress control group (SCT), and three stress groups with low, medium and high-doses of green tea polyphenols modulation respectively (SLG, SMG and SHG). The changes of behavioral performances were examined by open-field test, water maze and step-through test. Serum levels of cortisol, catecholamines, interleukin-6 and interleukin-2 were also detected.

The levels of serum cortisol were all increased obviously in the four stress groups. Furthermore, serum cortisol levels in SMG and SHG were decreased than that of SCT. The behavioral performances of SCT rats in open-field test, step-through test and water maze were all changed evidently in contrast to that of CT rats. On the one hand, the changes of behavioral performances in SLG rats were similar to SCT rats. On the other hand, these changes were improved in SMG and SHG rats. In addition, compared with CT group, the levels of plasma IL-6 and IL-1 were increased clearly in the four stress groups, and the contents of serum norepinephrine and dopamine in SCT and SLG groups were decreased dramatically. The serum norepinephrine and dopamine levels in SMG and SHG rats were increased in contrast to that of SCT rats.

Our results suggested that psychological stress can impair body' s behavioral performances, and moderate green tea polyphenols modulation may improve these abnormal changes.