TLR7激动剂咪喹莫特对MRL/lpr狼疮小鼠RORγt^+Th17细胞的影响

Effects of TLR7 agonist Imiquimod on RORγt+Th17 cells in MRL/lpr lupus mice

目的初步探讨TLR7激动剂咪喹莫特干预RORγt^+Th17细胞治疗MRL/lpr狼疮小鼠的免疫机理。方法将16周Balb/c正常小鼠和16周MRL/lpr狼疮小鼠随机分为生理盐水组、0.05 mg/kg咪喹莫特组、1 mg/kg地塞米组,每组5只,腹腔注射给药,1次/d,连续4周;采用流式细胞术检测小鼠脾脏中Th17(CD4^+IL-17A^+)细胞的比例和转录因子RORγt(RORγt^+Th17细胞)的表达水平,并分析细胞因子IL-17A(CD4^+IL-17A^+)和转录因子RORγt的相关性。结果 Balb/c正常小鼠中,咪喹莫特能降低脾脏中Th17细胞的比例(P<0.05),对Th17细胞转录因子RORγt的表达有下调趋势,但无统计学差异(P=0.616);MRL/lpr狼疮小鼠中,咪喹莫特能明显下调小鼠脾脏中Th17细胞的比例(P<0.01)和转录因子RORγt的表达(P<0.01);细胞因子IL-17A和转录因子RORγt呈显著的正相关性(r=0.911,P<0.000 1)。结论 TLR7激动剂咪喹莫特下调MRL/lpr狼疮小鼠脾脏中Th17细胞与转录因子RORγt的表达,降低IL-17的分泌,减缓SLE的发生,为咪喹莫特有望成为治疗SLE的药物提供了新的实验数据。

Studies have confirmed that serum IL-17 level and the frequency of Th17 cells are significantly elevated in patients with new-onset SLE,and serum IL-17 level is significantly associated with SLE disease activity index(SLED AI)and the number of Th17 cells.To explore the immune mechanism of TLR7 agonist Imiquimod in the treatment of MRL/lpr lupus mice by RORγt^+Th17 cells,16-week old normal Balb/c mice and 16-week old MRL/lpr lupus mice were randomly divided into 3 groups:normal saline group,0.05 mg/kg Imiquimod group,1 mg/kg dexamethasone group,with 5 mice in each group.All mice were administrated by intraperitoneal injection once a day for 4 weeks,then flow cytometry was used to detect the proportion of Th17(CD4^+IL-17 A^+)cells and theexpression level of transcription factor RORγt(RORγt^+Th17 cells)in the spleen of mice,and the correlation between cytokine IL-17 A(CD4^+IL-17 A^+)and transcription factor RORγt was analyzed.Data showed that Imiquimod reduced the proportion of Th17 cells in the spleen(P<0.05);the expression of Th17 cell transcription factor RORγt was down-regulated,but there was no statistical difference(P=0.616)in Balb/c normal mice.In MRL/lpr lupus mice,Imiquimodsignificantly down-regulated the proportion of Th17 cells(P<0.01)and the expression of transcription factor RORγt(P<0.01)in the spleen of mice.Furthermore,the cytokine IL-17 A and the transcription factor RORγt showed a significant positive correlation(r=0.911,P<0.000 1).Taken together,TLR7 agonist Imiquimod down-regulates the expression of Th17 cells and transcription factor RORγt in the spleen of MRL/lpr lupus mice,reduces the secretion of IL-17,and relieves the occurrence of SLE,which provides new experimental data for Imiquimod to be a drug for the treatment of SLE.