目的:探讨脓毒症时脑组织高迁移率族蛋白B1(HMGB1)表达规律及其与脑损伤的关系。方法40只C57BL/6小鼠随机(随机数字法)分为4组:假伤组、脓毒症组、侧脑室注射假伤组以及脓毒症动物侧脑室注射HMGB1抑制剂( BoxA)组。采用盲肠结扎穿孔复制脓毒症模型及全自动小鼠脑立体定位仪构建侧脑室置管模型,脓毒症后立即经侧脑室导管向侧脑室注射1μg BoxA,于24 h取出脑组织并分离出海马结构,采用组织免疫荧光、蛋白印迹分析、组织TUNEL染色及HE染色方法分别检测脑组织HMGB1、胱天蛋白酶( caspase)-3表达及组织凋亡、损伤等改变,组间差异采用单因素方差分析,两组之间采用t检验。结果(1)脓毒症组较假伤组海马组织HMGB1表达明显增加(22.74±9.29 vs.4.57±2.18, P<0.01);(2)脓毒症组与假伤组比较,海马组织细胞凋亡明显增加[(35±9.17) vs.(1.67±1.53), P<0.01]及caspase-3表达显著上调[(16.79±8.17) vs.(3.39±2.09), P<0.05],组织损伤明显加重;(3)侧脑室注射BoxA能有效地抑制海马组织HMGB1表达[(2.66±2.06) vs.(22.74±9.29), P<0.01];(4)侧脑室注射BoxA能减轻脑组织损伤,并减少组织细胞凋亡[(12±4.36) vs.(35±9.17), P <0.01]及 caspase-3表达[(4.10±2.11) vs.(16.80±8.17), P<0.05]。结论脓毒症状态下HMGB1表达增加与脓毒症脑组织损伤的发生、发展密切相关,中枢抑制HMGB1能明显减轻脓毒症脑损伤。
Objective To investigate changes in high mobility group box-1 protein ( HMGB1 ) level in brain tissues with severe sepsis, and the relationship between HMGB1 and septic brain injury.Methods Forty wild C57BL/6 mice were randomly ( random number) divided into 4 groups: sham group, sepsis group, cerebroventricular injection control group, and sepsis with BoxA ( HMGB1 inhibitor) cerebroventricular injection group.Septic model was reproduced by cecal ligation and puncture, and the cerebroventricular catheterization model was established by motorized mice brain stereotaxic instruments.After septic challenge, 1 μg BoxA was injected into the ventricle of brain via cerebroventricular catheter immediately.Mice were sacrificed and brains were harvested at 24 h after sepsis, and hippocampus tissue was separated immediately.Expressions of brain HMGB1 and caspase-3 changed in apoptotic neurons and brain injury were determined by brain tissue immunofluorescence, Western blotting, TUNEL and HE staining respectively.One-way analysis of variance ( ANOVA) for analyzing inter-group differences, student t test for comparing difference between two groups . Results (1) HMGB1 expression in hippocampus was significantly enhanced in the septic group compared to the sham group [ (22.74 ±9.29) vs.4.57 ±2.18, P<0.01].(2) Compared to the sham group, neuronal apoptosis [ (35 ±9.17) vs.(1.67 ±1.53) , P<0.01) and caspase-3 expressions [ (16.79 ±8.17) vs.( 3.39 ±2.09), P<0.05] were significantly increased in hippocampus with aggravated brain injury in the septic group.(3) Cerebroventricular injection of BoxA significantly inhibited HMGB1 in hippocampus [ (2.66 ± 2.06) vs.( 22.74 ±9.29), P<0.01];(4) Cerebroventricular injection of BoxA obviously alleviated acute brain injury, and decreased neuronal apoptosis [ ( 12 ±4.36 ) vs.( 35 ±9.17 ) , P <0.01 ] as well as caspase-3 activity [ (4.10 ±2.11) vs.(16.80 ±8.17), P<0.05].Conclusions The elevated expression of brain HMGB1 is closely related to pathogenesis and development of septic brain injury, and treatment with antagonist towards brain HMGB1 can markedly attenuate acute brain injury following severe sepsis.