Effect of Zaoshi Hewei formula on HPA axis, inflammatory factors and immune function in rats with dampness heat syndrome of spleen and stomach

Objective To study the effects of Zaoshi Hewei Formula on HPA axis, inflammatory factors and immune function in rats with dampness heat syndrome of spleen and stomach. Methods The animal model of damp heat syndrome of spleen and stomach was replicated by "environmental factors + fat diet + inflammatory factors". SPF SD male rats were randomly divided into 5 groups:normal group, model group, Zaoshi Hewei Formula high, middle and low dose groups(4, 2, 1 g·kg^-1). The content of adrenocorticotropic hormone releasing hormone (corticotropin releasing homone, CRH), corticotropin (adrenocorticotropic hormone, ACTH) and cortisol(Cor) were detected by radioimmunoassay. Immunohistochemistry was used to detect cyclic oxygenase-2 (cyclooxygenase, COX-2) in rat gastric mucous membrane. The expression level of tumor necrosis factor-α(TNF-α), rat interleukin 1β(IL-1β), interferon-γ(interferen-gamma, IFN-γ) and rat interleukin 4 (IL-4) were detected by ELISA. Results Compared with the normal group, the serum levels of CRH, ACTH, Cor, TNF-α, IL-1β, IFN-γ, IL-4 and IFN-γ/IL-4 in the rat serum in the model group were significantly increased(P<0.05). Compared with the model group, the above indexes in the serum of rats were significantly reduced by Zaoshi Hewei formula(P<0.05). Compared with the high dose of Zaoshi Hewei Formula group, the content of CRH, ACTH and Cor in the low dose group was significantly higher(P<0.05). The content of each index in the middle dose group was slightly higher than that of the high dose group, and there was no significant difference between the groups. The improvement of TNF-α and COX-2 was significantly lower than that of high dose group (P<0.05), but there was no significant difference of the IL-4 index between the middle dose group and high dose group, and the values of IFN-γ/IL-4 in the middle dose group were significantly higher than that of high dose group (P<0.05). Conclusion Zaoshi Hewei Formula can effectively improve the state of disease activity in rat model of dampness heat syndrome of spleen and stomach, which may be related to adjusting the content of CRH, ACTH and Cor of HPA axis by reducing the related indexes of HPA axis, reducing the inflammatory response of the body, improving the immune state and restoring the dynamic balance of Th1/Th2 in the immune system.