MyD88非依赖性信号通路在枸杞多糖抑制糖尿病小鼠肿瘤坏死因子α中的作用

目的: 研究枸杞多糖对髓样分化因子88（MyD88）非依赖性信号通路的影响，探讨枸杞多糖影响TNF-α生成的机制。方法: 采用高糖高脂饲料联合链脲菌素诱导MyD88基因敲除小鼠形成2型糖尿病模型。将造模成功的小鼠随机分为模型对照组、阳性对照组和枸杞多糖组，另取8只小鼠作为健康对照组。干预三个月后，采用实时定量RT-PCR和蛋白质印迹法检测小鼠腹腔巨噬细胞中TRAM、TRIF、TRAF6、RIP1和TNF-α基因和蛋白表达，ELISA法测定小鼠血清TNF-α水平。结果: 枸杞多糖抑制了糖尿病小鼠腹腔巨噬细胞中Tram、Trif、Traf6和Tnf-α的基因表达，激活了Rip1基因（均P < 0.05），但对TRAM、TRIF、TRAF6、RIP1和TNF-α蛋白表达和血清TNF-α水平无影响（均P > 0.05）。结论: 枸杞多糖可能不能通过MyD88非依赖性信号通路抑制TNF-α的生成。
Abstract: Objective: To investigate the effect of Lycium barbarum polysaccharides (LBPs) on TLR/NF-κB independent pathway and serum tumor necrosis factor (TNF-α) level in diabetic MyD88-knockout mice. Methods: Diabetes was induced by feeding high-fat/high-sugar diet and injection of low-dose streptozotocin in MyD88-knockout mice. The diabetic mice were randomly divided into model group, positive control group and LBPs group. The expressions of TRAM, TRIF, TRAF6, RIP1 and TNF-α mRNA and proteins in mouse peritoneal macrophages were detected by real-time RT-PCR and Western blotting after LBPs treatment for 3 month. Serum TNF-α was determined with ELISA kit. Results: Real time RT-PCR showed that compared with model group, the relative expressions of Tram, Trif, Traf6 and Tnf-α mRNA in macrophages of LBPs group were significantly decreased and expression of Rip1 was significantly increased (all P < 0.05). Expression of TRAM, TRIF, TRAF6, RIP1 and TNF-α proteins as well as serum TNF-α level had no significant difference between LBPs group and model group (all P > 0.05). Conclusion: LBPs may not inhibit serum TNF-α level through TLR/NF-κB independent pathway. Key words: Myeloid differentiation factor 88/physiology Signal transduction Tumor necrosis factor-alpha/biosynthesis Polysaccharides/pharmacology Lycium barbarum/chemistry Diabetes mellitus, type 2 Disease models, animal Cells, cultured