N-乙酰半胱氨酸(NAC)对体外LPS刺激下小鼠巨噬细胞HIF-1α表达的影响

Effect of N-acetylcysteine on HIF-1α expression in murine peritoneal macrophages induced by lipopolysaccharide in vitro

目的:探讨NF-κB抑制剂N-乙酰半胱氨酸(NAC)对脂多糖(LPS)诱导小鼠巨噬细胞内HIF-1表达的影响及意义。方法:取健康Balb/c小鼠,分离腹腔巨噬细胞并将其分为正常对照组、LPS刺激组、不同剂量NAC加LPS组。采用RT-PCR检测各组HIF-1α、TNF-αmRNA表达,细胞免疫化学检测HIF-1α、VEGF的蛋白表达。结果:与LPS刺激组比较,NAC+LPS组HIF-1αmRNA表达无明显差异、TNF-αmRNA明显减少,HIF-1α、VEGF蛋白表达显著减少(P<0.01)。结论:NAC可降低LPS刺激下小鼠巨噬细胞TNF-αmRNA表达,TNF-α的降低可能通过HIF-1α转录后途径下调该蛋白的表达,进而下调VEGF表达。提示在急性炎性反应中,NF-κB可能通过增加TNF-α在转录后水平影响HIF-1α的表达。

Objective To explore the effect of nuclear factor-κB inhibitor,N-acetylcysteine on the HIF-1α expression of peritoneal macrophages in vitro induced by lipopolysaccharide（LPS）.Method The peritoneal macrophages from healthy Balb/c mice were collected and then incubated after adding NAC and LPS（NAC＋LPS group） or LPS（experimental group） or PBS（control group） for 10 h.The mRNA expression of HIF-1α and TNF-α in the cells were measured by semi-quantitive RT-PCR.The protein expression of HIF-1α and VEGF were detected by method of immunocytochemistry.Results Under normoxic environment in vitro,both the expression level of HIF-1α and VEGF proteins and that of TNF-α mRNA were down-regulated by NAC（P0.01）,but the expression level of HIF-1α mRNA in the LPS-stimulated macrophages had no change（P0.05）.Conclusion As it decreases the mRNA expression of TNF-α induced by LPS in vitro,NAC can down-regulate the protein expression of HIF-1α in macrophages by post-transcription mechanism,and then the expression of VEGF,which is a target gene of HIF-1,decreases.These data indicate that NF-κB signal transduction pathway may participate in LPS inducing the HIF-1α accumulation by up-regulation the TNF-α expression.