内毒素血症肝损伤幼年大鼠肝脏NF-κB的变化

NF-κB levels in the liver of young rats with endotoxemic liver injury

摘要:

目的：研究内毒素血症肝损伤幼年大鼠肝脏NF-κB的变化及与TNF-α、IL-6的关系。方法：18日龄Wistar大鼠40只随机分为正常对照组和内毒素血症组，内毒素血症组根据制模后取标本时间不同分2 h、6 h、12 h、24 h 4个亚组（n=8）。内毒素血症组腹腔注射LPS 5 mg/kg制备内毒素血症动物模型。观察各组肝细胞的病理改变，ELISA测定肝组织匀浆TNF-α、IL-6含量，赖氏法测血清丙氨酸转氨酶（ALT）浓度，免疫组化法检测肝组织NF-κB活化水平。结果：光镜下内毒素血症组肝组织损伤以6 h最明显，损伤等级评分在各个时间点均较正常对照组高（P<0.05）；内毒素血症组ALT水平6 h、12 h及24 h均较正常对照组增高（P<0.05）；内毒素血症组各个时间点肝细胞NF-κB p65蛋白表达的阳性细胞百分比均较正常对照组高（P<0.05）；肝组织TNF-α、IL-6检测显示内毒素血症组6 h、12 h高于正常对照组（P<0.05）。结论：内毒素血症可引起肝损伤，导致肝细胞的破坏和肝功能的改变；NF-κB的活化参与了内毒素血症肝损伤的发生，可能是通过介导炎症因子TNF-α和IL-6的合成使肝细胞发生炎性损伤。［中国当代儿科杂志，2010，12（10）：804-808］

Abstract:

OBJECTIVE: To study hepatic NF-κB level following endotoxemic liver injury, and its relationship with hepatic TNF-α and IL-6 levels in young rats. METHODS: Forty 18-day-old rats were randomly assigned to a normal control and an endotoxemia group. Endotoxemia was induced by lipopolysaccharide injection (LPS, 5 mg/kg). The endotoxemia group was subdivided into four groups sampled at 2, 6, 12 and 24 hrs after LPS injection (n=8 each). Pathological changes in liver cells were observed under a light microscope. TNF-α and IL-6 levels in liver tissue homogenates were measured using ELISA. Reitman-Frankel was used to measure serum ALT concentrations. NF-κB activation level in liver tissues was detected by immunohistochemistry. RESULTS: Liver tissue injury was the most obvious 6 hrs after LPS injection under the light microscope, and the damage rating of liver tissues was significantly higher in the endotoxemia group than that in the normal control group at all time points (P<0.05). ALT levels in the endotoxemia group were significantly higher than those in the normal control group 6, 12 and 24 hrs after LPS injection (P<0.05). NF-κB p65 protein expression in liver cells (percentage of nuclear positive cells) in the endotoxemia groups was significantly higher than that in the normal control group (P<0.05). TNF-α and IL-6 levels in liver tissue homogenates in the endotoxemia groups were significantly higher than those in the normal control group 6 and 12 hrs after LPS injection (P<0.05). CONCLUSIONS: Endotoxemia can cause liver injury, resulting in liver cell damage and changes in liver function. NF-κB activation is involved in endotoxemic liver injury which may be mediated by inflammatory cytokines TNF-α and IL-6 synthesis. ［Chin J Contemp Pediatr, 2010, 12 (10):804-808］