益生菌VSL#3对DSS大鼠结肠炎TLR4-NF-κB通路的调节作用

The regulating effects of probiotics VSL#3 on the TLR4-NF-κB pathway in rats with DSS-induced colitis

目的阐明益生菌VSL#3对硫酸葡聚糖钠(DSS)诱导结肠炎大鼠TLR4-NF-κB通路的影响,深入探讨VSL#3对结肠黏膜炎症免疫调控机制。方法将33只Sprague-Dawly大鼠(SD大鼠)分为正常组、DSS造模组以及益生菌治疗组。5%DSS溶液自由饮用一周,构建溃疡性结肠炎模型。观察和评价大肠黏膜的组织学损伤,计算DAI评分以及病理学评分;使用real-time PCR检测结肠组织TLR4、NF-κB、TNF-α、IL-1βmRNA的表达水平;Western-Blot检测TLR4、NF-κB蛋白的表达水平;应用酶联免疫吸附测定(ELISA)检测血清中TNF-α和IL-1β的表达。结果益生菌治疗组DAI评分、病理学评分均低于DSS造模组(P<0.05);益生菌治疗组大鼠结肠组织中TLR4、NF-κB、TNF-α、IL-1β的mRNA水平与DSS造模组相比表达下调,差异具有统计学意义(P<0.05);与DSS造模组相比,益生菌治疗组SD大鼠结肠组织TLR4、NF-κB p65蛋白水平下调,血清TNF-α、IL-1β表达水平降低,差异具有统计学意义(P<0.05)。结论益生菌VSL#3可能是通过抑制TLR4-NF-κB通路,发挥其抑制免疫,减轻炎症反应的作用,从而达到治疗溃疡性结肠炎的目的。

Objective To elucidate the effects of probiotic VSL#3 on the TLR4-NF-κB pathway in rats with DSS-induced colitis,and to further investigate the immunoregulatory mechanism of VSL#3 on colon mucosa inflammation.Methods 33 Sprague-Dawly rats(SD rats)were randomly divided into three groups.Those rats were given access to 5%dextran sulfate sodium(DSS)solution ad libitum for a week to build the model of experimental acute enteritis.Observe and evaluate the histological damage of colorectal mucosa,calculate the DAI score and pathological score.Real-time PCR was used to detect the mRNA levels of TLR4,NF-κB,IL-1β,and TNF-αin the rat colon mucosa.Western-Blot was used to detect the protein levels of TLR4 and NF-κB in colon mucosa.Serum IL-1βand TNF-αin rats were detected by ELISA.Results DAI scores and pathology scores in probiotics groups were lower than those in the model group(P<0.05).The mRNA levels of TLR4,NF-κB,TNF-α,and IL-1βin the colonic tissue of the probiotic treatment group were down regulated compared with those of the DSS mod model,and the differences were statistically significant(P<0.05).Compared with the DSS model group,the levels of TLR4 and NF-κB p65 protein in the colon of the SD rats treated with probiotics were decreased,and the levels of serum TNF-αand IL-1βwere decreased,the differences were statistically significant(P<0.05).Conclusion VSL#3 may achieve the goal of treating ulcerative colitis by inhibiting the TLR4-NF-κB pathway so as to inhibit immune and suppress inflammatory responses.