Jingfang granules ameliorate inflammation and immune disorders in mice exposed to low temperature and high humidity by restoring the dysregulation of gut microbiota and fecal metabolites

The dramatic changes in global climate on human health have been extremely severe. The immune disorder caused by low temperature and high humidity (LTHH) have become a severe public health issue. Clinically, Jingfang granule (JF) has the effect of dispelling cold and eliminating dampness, and is widely used in the treatment of cold caused by wind and cold, autoimmune diseases, and COVID-19 with cold-dampness stagnating in the lung pattern. Our study aims to elucidate the effect of JF on LTHH-induced immune disorders in mice as well as the underlying mechanisms. In this study, JF increased the spleen index, improved fecal character, repaired the intestinal barrier and alleviated intestinal inflammatory responses. Most importantly, JF ameliorated immune disorder in LTHH mice, which was manifested primarily by the significant increase in gdT, CD8+ Tcm, and CD8+ Tem cells, as well as the decrease in TH1, TH17, CD4+ Tem1, CD4+ Tem2, immature NK, mature NK cells, and M1-like macrophages. Interestingly, the JF treatment not only regulated the gut microbiota by decreasing the abundance of harmful bacteria, as well as up-regulating the abundance of beneficial bacteria, but also ameliorated the metabolic disorders by reversing the levels of fecal metabolites to normality. The results of the correlation analysis demonstrated a significant association among gut microbiota, fecal metabolites and immune cells. In addition, JF inhibited the TLR4/NF-κB/NLRP3 pathway in LTHH mice. In conclusion, our results suggested that JF alleviated inflammation and immune disorders in LTHH mice by restoring gut microbiota and fecal metabolism.