核转录因子-κB活化介导内毒素抑制白蛋白的表达

Role of NF-κB activation in lipopolysaccharide inhibitting albumin expression in rat hepatocytes

目的 在原代大鼠肝细胞培养体系中 ,观察内毒素诱导白蛋白表达的下降是否由核转录因子(nuclearfactor κB ,NF κB)活化介导。方法 原代大鼠肝细胞随机分为 5组 ,分别经生理盐水、 1ng/ml、0 0 1μg/ml、 0 1μg/ml和 1μg/ml内毒素 ,分别作用后 2 4h检测肝细胞NF κB的表达 (凝胶电泳迁移率测定 ,EMSA)与白蛋白的变化 (酶链免疫检测法 ,EIA)。同时 ,另一组肝细胞使用NF κB特异性阻断剂SN5 0预处理 30min后 ,再用 1μg/ml内毒素刺激 2 4h后观察白蛋白的变化。 结果 内毒素组肝细胞白蛋白的表达明显下降 ,而NF κB的表达较生理盐水组明显增强 ,并且白蛋白表达受抑和NF κB活化随内毒素浓度的提高明显增强。三种浓度的SN5 0均可完全阻断内毒素诱导的白蛋白表达的下降。结论 核转录因子NF κB的活化参与了内毒素抑制肝细胞白蛋白的表达 。

Objective To investigate whether the reduction of albumin expression induced by LPS was mediated by activating nuclear factor kappaB(NF-κB) in cultured rat hepatocytes.Methods Primary rat hepatocytes were divided into five groups treated with normal saline,LPS(1 ng/ml),LPS(0.01 μg/ml),LPS(0.1 μg/ml),or LPS(1 μg/ml) for 24 h.The albumin level in the supernatant and NF-κB activity in hepatocytes were measured.Hepatocytes were pretreated for 30 min with SN50(a highly selected inhibitor of NJ-κB)at different concentrations(10 μg/ml,30 μg/ml and 50 μg/ml).After 24 hours of treatment with different comentration of LPS,the culture medium was tested for albumin level.Meanwhile,NF-κB activity in hepatocytes was assayed.Results LPS dramatically decreased albumin expression and enhanced NF-κB activity in rat hepatocytes,especially in the 1 μg/ml LPS group.This reduction in albumin expression induced by LPS was completely blocked by SN50 at different concentrations.Conclusion The results suggest that LPS inhibits albumin expression by activating NF-κB.NF-κB is the most important reason that causes albumin expression decrease.