Taurohyodeoxycholic acid ameliorates inflammatory response in a murine model of ovalbumin (OVA)-induced allergic asthma

Abstract

Taurohyodeoxycholic acid (THDCA), a naturally occurring conjugated bile acid compound formed by the condensation of taurine and deoxycholic acid, possesses various biological activities. Present study attempted to assess whether THDCA can alleviate airway inflammation in allergic asthma through regulating the immune balance among CD4⁺ T cell subgroups. Mice were exposed with ovalbumin (OVA) to build allergic asthma model and THDCA was administrated orally. Pulmonary histopathology analysis was evaluated by H&E and PAS staining. The typical cytokines and transcription factors of CD4⁺ T cell subgroups were determined, and the proportion of CD4⁺ T cell subgroups were analyzed. The oral administration of THDCA attenuated OVA-induced asthma by decreasing inflammatory cell counts in the bronchoalveolar lavage fluid (BALF), reducing tIgE and OVA-sIgE concentration in the serum, and improving histopathological changes in the lung tissue. In addition, THDCA reduced the secretion of IL-4, IL-5, IL-13, IL-6, TNF-α, IL-17A, and TGF-β1, but increased the production of IFN-γ, IL-10, and IL-35 in the BALF and lung tissue. Meanwhile, THDCA inhibited GATA3 and RORγt expression, and STAT3 phosphorylation, but improved T-bet and Foxp3 expression in the lung tissue. Besides, THDCA restored the proportion of CD4⁺ T cell subgroups in the spleen and peripheral blood. These findings indicated that THDCA may have therapeutic potential for treating allergic asthma by regulating the immune balance of CD4⁺ T cell subgroups.