In months 4, the plama corticosterone level of CES group declined, but was never lower than basal level of month 0. (4) In months 2 and 4, NK cell activity of CES group is significantly lower than that of C group (P=0.046 and P=0.003).

• 应激2月时段和4月时段NK细胞活性较同期对照组下降，P值分别为0.；046和0