Huangqin-Tang decoction (HQT) is a classic traditional Chinese herbal formulation that is widely used to ameliorate the symptoms of
gastrointestinal disorders, including
inflammatory bowel disease (IBD). This study was designed to investigate the therapeutic potential and immunological regulatory activity of HQT in experimental
colitis in rats. Using an animal model of
colitis by intrarectally administering 2,4,6-trinitrobenzenesulfonic
acid (TNBS), we found that administration of HQT significantly inhibited the severity of TNBS-induced
colitis in a dose-dependent manner. In addition, treatment with HQT produced better results than that with
mesalazine, as shown by improvedweight loss
bleeding and diarrhoea scores, colon length, and intestinal
inflammation. As for potential immunological regulation of HQT action, the percentages of Th1 and Th17 cells were reduced, but those Th2 and Treg cells were enhanced in LPMCs after HQT treatment. Additionally, HQT lowered the levels of Th1/Th17-associated
cytokines but increased production of Th2/Treg-associated
cytokines in the colon and MLNs. Furthermore, we observed a remarkable suppression of the Th1/Th17-associated
transcription factors T-bet and ROR-γt. However, expression levels of the Th2/Treg-associated
transcription factors GATA-3 and Foxp3 were enhanced during treatment with HQT. Our results suggest that HQT has the therapeutic potential to ameliorate TNBS-induced
colitis symptoms. This protective effect is possibly mediated by its effects on CD4(+) T cells subsets.