Huangtu Decoction regulates macrophage M1/M2 polarization to alleviate DSS- and rhubarb-induced Deficiency-Cold Pattern in Ulcerative Colitis by inhibiting the HIF-1α signaling pathway.

Abstract

ETHNOPHARMACOLOGICAL RELEVANCE: Huangtu Decoction (HTD), a classic formula in TCM, was first documented in the Synopsis of the Golden Chamber and later included in numerous TCM texts. This formula is commonly used to treat various gastrointestinal disorders, including diarrhea, bloody stools, irritable bowel syndrome, and ulcerative colitis (UC). AIM OF THE STUDY: This study aimed to explore the therapeutic efficacy and mechanism of HTD in treating Deficiency-Cold Pattern in Ulcerative Colitis (DCP-UC). The focus was on examining whether HTD alleviates colitis symptoms by regulating macrophage polarization via the HIF-1α signaling pathway. MATERIALS AND METHODS: We established DSS- and rhubarb-induced DCP-UC models in mice, along with an LPS-stimulated RAW264.7 macrophage inflammation model, to evaluate the effects of HTD on colonic injury, inflammatory responses, and macrophage polarization. To verify the central role of macrophages in HTD efficacy, we conducted macrophage depletion experiments in vivo. Additionally, we induced differentiation of M1 and M2-type bone marrow-derived macrophages (BMDMs) and explored the impact of HIF-1α on HTD efficacy by activating and overexpressing HIF-1α. RESULTS: HTD therapy significantly alleviated colitis symptoms, reduced colonic histopathological damage, and effectively suppressed intestinal inflammation. Concurrently, it decreases M1 macrophage markers and increases M2 markers, suggesting that HTD modulates macrophage polarization. Macrophage depletion experiments indicate that HTD's therapeutic efficacy may depend on macrophages. In vitro BMDM experiments showed that HTD inhibited HIF-1α expression in M1 macrophages, thereby reducing proinflammatory factors. However, overexpression and activation of HIF-1α could reverse this effect, implying that HIF-1α is a potentially crucial target for HTD in regulating intestinal inflammation. CONCLUSION: HTD may exert its therapeutic effects by suppressing the HIF-1α signaling pathway, which in turn may promote a phenotypic switch of macrophages from the proinflammatory M1 state to the anti-inflammatory M2 state. These findings suggest that HTD represents a promising potential therapeutic approach for DCP-UC.