RESUMO
OBJECTIVE: To explore the effects of Jiawei Xiaoyao Pills (JWXYP) on immune system of mice exposed to chronic emotional stress, and to compare its effects with blockage of hypothalamic-pituitary-adrenal cortex axis (HPAA) by metyrapone. METHODS: Eighty male mice were randomly divided into eight groups: normal saline-treated group, normal saline-treated stress group, JWXYP-treated group, JWXYP-treated stress group, metyrapone-treated group, metyrapone-treated stress group, metyrapone and JWXYP-treated group and metyrapone and JWXYP-treated stress group. A box of electrical shock was used to induce chronic emotional stress in mice. The metyrapone was applied to blocking the HPAA. The JWXYP, a classical formula of traditional Chinese medicine, which can alleviate the damages caused by chronic emotional stress, was also used to compare its effects with that of metyrapone. The body weight, thymus index, rate of apoptosis in thymus, serum concentration of glucocorticoid, activity of natural killer cells, lymphocyte transmission rate of mice were all measured and examined after interventions. The pathological changes of thymus tissue were observed. RESULTS: The thymus index, activity of natural killer cells and lymphocyte transmission rate were lower while the rate of apoptosis in thymus as well as the severity degree of pathological damages in thymus tissue were increased in the different drug-treated stress groups as compared with those in the corresponding drug-treated groups without stress. The activity of natural killer cells and the lymphocyte transmission rate induced by lipopolysaccharide were increased while the serum concentration of glucocorticoid and the severity degree of pathological damages in thymus tissue were decreased in both the metyrapone-treated stress group and JWXYP-treated stress group as compared with those in the normal saline-treated stress group. The combined intervention of metyrapone and JWXYP did not show better effects on immune system in mice exposed to chronic emotional stress than single metyrapone or JWXYP intervention. CONCLUSION: Blockage of HPAA by metyrapone intervention shows a significant protective effect on immune system in mice exposed to chronic emotional stress, and the JWXYP also exerts a similar protective effect against damages induced by chronic emotional stress. The HPAA may be one of the action targets of protective effects of JWXYP.