红芪多糖干预内毒素诱导的大鼠葡萄膜炎的机制

Mechanism of intervention of hedysarum polybotrys saccharide in endotoxin-induced uveitis in rats

目的探讨红芪多糖(hedysarum polybotrys saccharide,HPS)在内毒素诱导的大鼠葡萄膜炎发病中的作用及对Toll样受体4(Toll-like receptor 4,TLR-4)信号转导通路中关键分子肿瘤坏死因子受体相关因子6(tumor necrosis factor receptor-associated factor 6,TRAF6)及TIR功能区接头蛋白诱导的干扰素β(TIR-domain-containing adapter-inducing interferon-β,TRIF)表达的影响。方法选用SPF级健康成年Wistar大鼠40只,随机分为内毒素诱导的葡萄膜炎(endotoxin induced uveitis,EIU)模型组、HPS组、HPS+内毒素组、正常对照组(normal control,NC)组,每组10只。EIU模型组大鼠采用皮下注射1 mg·kg-1内毒素的方法建立大鼠急性前葡萄膜炎动物模型。HPS+内毒素组在内毒素注射前1 h给予腹腔注射HPS 400 mg·kg^-1。HPS组大鼠只注射HPS 400 mg·kg^-1。每2 h用裂隙灯观察大鼠眼前节炎症反应,注射后的0 h、6 h、12 h、18 h、24 h对各组眼部临床炎症反应进行评分。注射后24 h组织病理学检查炎症反应水平。RT-PCR检测核因子-κB、TRAF6及TRIF mRNA的表达。结果 NC组大鼠24 h内眼前节未见炎症反应。注射后24 h,EIU模型组可见虹膜血管扩张明显,瞳孔区大量白色渗出,HPS组仅可见虹膜血管扩张,未见其他眼部炎症反应,HPS+内毒素组大鼠可见虹膜血管扩张和瞳孔缘少量渗出。比较不同组间的大鼠眼部临床炎症反应评分可见,NC组与EIU模型组、HPS+内毒素组、HPS组比较,差异均有统计学意义(均为P<0.001);EIU模型组与HPS+内毒素组、HPS组比较,差异均有统计学意义(均为P<0.05);HPS+内毒素组与HPS组比较,差异有统计学意义(P<0.001)。RT-PCR结果显示,HPS可降低核因子-κB mRNA和TRAF6 mRNA的表达(P<0.001),HPS对TRIF的表达无明显影响(P=0.236)。结论 HPS可能通过抑制TRAF6核酸的表达缓解EIU的炎症反应,HPS对TRIF的表达无明显影响。

Objective To investigate the effect of hedysarum polybotrys saccharide(HPS) on endotoxin-induced uveitis(EIU) in rats and to explore the effect on the expression of tumor necrosis factor receptor-associated factor 6(TRAF6)and TIR-domain-containing adapter-inducing interferon-β(TRIF)in the Toll-like receptor 4(TLR-4) signal transduction pathway in EIU.Methods Experiment select the SPF healthy adult Wistar rats,40 rats were randomly divided into four groups.EIU group,hedysarum polybotrys saccharide treatment(HPS+LPS) group,hedysarum polybotrys saccharide control(HPS) group,normal control(NC) group.Ten rats in each group.EIU was established by subcutaneous injection of 1 mg·kg-1 lipopolysaccharide(LPS).HPS(400 mg·kg-1) was given through intraperitoneal injection 1 h before the LPS induction in HPS treatment group.Rats in the HPS control group were only injected with 400 mg·kg-1 of HPS.The inflammation of rats was observed every 2 h with slit lamp,and each group was graded at 0 h,6 h,12 h,18 h and 24 h after injection.Histopathological examination of inflammatory was performed 24 h after injection.Real-time quantitative PCR were used to determine the expression of nuclear factor-kappa B(NF-κB),TRAF6 and TRIF.Results No inflammation was observed in NC group within 24 h.24 h after injection,iris blood vessel dilation and a large amount of white exudation was observed in the pupil area in the EIU group.Only iris blood vessel dilation was observed in the HPS group.In the HPS+LPS group,iris blood vessel dilation and a small amount of exudation in the pupil margin were observed.Compared clinical scores of rats in different groups,and the differences were statistically significant among all groups(all P<0.001).Compared with HPS+LPS group and HPS group,the difference of EIU group was statistically significant(both P<0.05).The difference of inflammation between the LPS+HPS group and the HPS group was statistically significant(P<0.001).Real-time quantitative PCR results showed that HPS could reduce the expression of NF-κB and TRAF6 mRNA(both P<0.001),while HPS had no significant effect on the expression of TRIF(P=0.236).Conclusion HPS can restrain the intraocular inflammation in EIU by inhibiting the expression of TRAF6 mRNA.HPS has no significant effect on the expression of TRIF.