鲜地黄通过调节Treg/Th17平衡与肠道菌群结构改善小鼠过敏性紫癜的作用及机制OA

Objective To investigate the effect and mechanism of fresh Rehmanniae Radix on Henoch-Schönlein purpura(HSP)mice based on Treg/Th17 balance and gut microbiota structure.Methods Male ICR mice were randomly divided into blank group,model group,positive drug group(montelukast 0.3 mg·kg-1),and fresh Rehmanniae Radix low-and high-dose groups(fresh rehmannia juice 4,8 mL·kg-1),with 8 mice in each group.The HSP mouse model was established by tail vein injection of India ink combined with intragastric/tail vein injection of ergoprotein solution dissolved in HCl-acidified water.Drugs were administered intragastrically once daily for 4 consecutive weeks.Histopathological changes of skin tissue were observed by HE staining;immunoglobulin A(IgA)protein expression in skin tissue was detected by immunofluorescence;serum levels of interleukin-10(IL-10),interleukin-4(IL-4),interleukin-17(IL-17),interleukin-22(IL-22),transforming growth factor-β(TGF-β),tumor necrosis factor-α(TNF-α)and IgA were measured by ELISA;the proportion of Th17/Treg cells in peripheral blood was determined by flow cytometry;the expression levels of related genes in colon tissue were detected by RT-qPCR;and microbial diversity of gut microbiota was analyzed by 16S rDNA gene sequencing.Results(1)Compared with the blank group,the model group showed obvious skin tissue edema with papule-like erythematous spots on the skin surface;IgA protein expression was significantly increased(P＜0.01);serum levels of IgA,IL-4,IL-22,IL-17 and TNF-α were significantly elevated(P＜0.05,P＜0.01),while IL-10 and TGF-β levels were significantly decreased(P＜0.01);the proportion of Th17 cells in peripheral blood was significantly increased(P＜0.01),whereas the proportion of Treg cells and the Treg/Th17 ratio were significantly decreased(P＜0.05,P＜0.01);mRNA expression of IL-10,Foxp3,TGF-β,Occludin,MUC2,AHR and IL-22 in colon tissue was significantly down-regulated(P＜0.05,P＜0.01),while IL-17A,RORγt and IL-23 mRNA expression was significantly up-regulated(P＜0.05,P＜0.01).Compared with the model group,skin edema and microvascular dilation were markedly alleviated in the fresh Rehmanniae Radix high-dose group;IgA protein expression in skin tissue was significantly reduced in all treatment groups(P＜0.01);serum levels of IL-4,IL-22 and TNF-α were significantly decreased(P＜0.05,P＜0.01),and IL-10 and TGF-β levels were significantly increased(P＜0.01)in both fresh Rehmanniae Radix low-and high-dose groups;serum IgA and IL-17 were significantly decreased in the fresh Rehmanniae Radix high-dose group(P＜0.05);the proportion of Th17 cells in peripheral blood was significantly decreased(P＜0.01)and the Treg/Th17 ratio was significantly increased(P＜0.05,P＜0.01)in both fresh Rehmanniae Radix dose groups,and the proportion of Treg cells in peripheral blood was significantly increased in the high-dose group(P＜0.05);mRNA expression of IL-10,Foxp3,Occludin,Claudin-1,ZO-1,MUC2 and IL-22 in colon tissue was significantly up-regulated(P＜0.05,P＜0.01),and IL-17A and IL-23 mRNA expression was significantly down-regulated(P＜0.05)in both dose groups;TGF-β and AHR mRNA expression was significantly up-regulated(P＜0.05)and RORγt mRNA expression was significantly down-regulated(P＜0.05)in the high-dose group.(2)Compared with the blank group,the gut microbiota dysbiosis index was significantly increased in the model group and fresh Rehmanniae Radix high-dose group(P＜0.01,P＜0.001).Compared with the model group,the gut microbiota health index was significantly elevated in the fresh Rehmanniae Radix high-dose group(P＜0.001).Fresh Rehmanniae Radix may regulate gut microbiota structure by increasing the abundance of Lactobacillus_intestinalis and Bifidobacterium_pseudolongum and their metabolites,thereby activating the intestinal AHR receptor and regulating Treg/Th17 immune balance.Conclusion Fresh Rehmanniae Radix can ameliorate symptoms in HSP mice by regulating Th17/Treg immune balance,modulating gut microbiota homeostasis,and enhancing intestinal barrier function.