1,25(OH)_2D_3抑制肝星状细胞激活和调控Th细胞分化治疗肝纤维化

Treatment effect of 1,25(OH)_2D_3 on liver fibrosis by inhibiting HSC activation and regulating Th cell differentiation

目的明确1,25-二羟基维生素D_3[1,25-dihydroxyvitamin D_3,1,25(OH)_2D_3]对肝纤维化的治疗作用及其作用机制。方法病理学检查和肝功能血生化检查评估肝纤维化程度;免疫组化检测α-SMA、TGF-β和collagen I表达观察肝星状细胞(hepatic stellate cells,HSC)激活水平;流式细胞实验、ELISA、RT-PCR等衡量1,25(OH)_2D_3对CD4+T细胞亚群分化的影响。结果与肝纤维化模型组相比,1,25(OH)_2D_3治疗组肝细胞状态明显恢复。肝纤维化小鼠肝脏中collagen I、TGF-β和α-SMA表达明显增多(P<0.05),1,25(OH)_2D_3治疗后表达明显下降(P<0.05)。1,25(OH)_2D_3治疗后Th1细胞和Th17细胞比例降低(P<0.05)、Th2细胞比例增加(P<0.05)。1,25(OH)_2D_3治疗组小鼠的IFNγ、IL-17A和IL-22因子浓度水平较肝纤维化小鼠明显降低,IL-4浓度升高(P<0.01);RORγt和T-bet表达量降低,GATA3表达升高(P<0.01)。结论 1,25(OH)_2D_3通过降低肝星状细胞激活水平以及调控肝纤维化中Th细胞的分化减轻肝纤维化。

Objective To explore the effect of 1-alpha, 25-dihydroxy-cholecalcifero （ 1,25 （OH） 2D3） on liver fibrosis and its mechanism. Methods Degree of liver fibrosis was assessed through pathological detection and blood biochemical examination of liver function. Immunohistochemical assay was used to detect expressions of α- SMA, TGF-β and collagen I to observe activation level of hepatic stellate cells. Impact of 1,25 （OH）2D3 on CD4^＋T cell differentiation was analyzed by flow cytometry, ELISA, and RT-PCR. Results 1,25 （OH）2D3 improved the structure of the liver tissue and liver fibrosis. Expressions of collagen I, TGF-β and α-SMA were significantly elevated in the liver tissue in rats with fibrosis （P 〈 0.05 ） but were markedly decreased after treatment with 1,25 （OH） 2D3 （P 〈 0.05）. After 1,25 （OH）2D3 treatment, the proportion of Thl7 cells reduced while that of Th2 increased ; concentration levels of IFNγ, IL-17A, and IL-22 markedly declined but IL-4 elevated （P〉0.01） ; and expressions of RORyt and T-bet decreased whereas GATA3 expression increased （P〉0.01） ; as compared with those in the control group. Conclusions 1,25 （OH） 2D3 can alleviate the degree of liver tissue by lowering HSC activation and regulating Th cell differentiation.