肾脏缺血再灌注损伤过程中天然免疫分子高迁移率族蛋白B1释放变化

目的 观察高迁移率族蛋白B1(HMGB1)在小鼠肾脏缺血再灌注损伤(IRI)中的表达变化.方法 建立小鼠IRI模型,再灌注0、3、6 h或24 h后取外周血及左肾,测定血肌酐(Cr)和尿素氮(BUN)水平,免疫组织化学及Western blot检测肾组织全蛋白和胞质蛋白HMGB1的表达,并观察病理学变化(HE)及细胞凋亡.结果与假手术组比较,再灌注0 h时小鼠血清Cr和BUN无明显升高,而再灌注3、6、24 h后呈阶梯性显著性升高.假手术组肾组织HMGB1几乎均表达于细胞核内,而肾脏缺血损伤后HMGB1即开始在(主要是肾小管上皮细胞)胞质或胞外表达,且HMGB1在细胞核外的表达量在再灌注3 h时最强,之后缓慢减弱,而24 h内细胞总蛋白HMGB1表达量未见明显变化.再灌注0、24 h病理损伤渐进性加重,而凋亡细胞显著性增加.结论 HMGB1在肾IRI早期表达总量恒定而表达部位发生改变,且表达部位的改变先于肾功能的变化,HMGB1可能作为重要早期炎症因子在IRI启动中发挥作用.

The release pattern of natural immune cytokine high mobility group protein B1 during renal ischemia reperfusion injury

Objective To investigate the release pattern of high mobility group protein B1 (HMGB1) during renal ischemia/reperfusion injury (IRI) and the relative mechanism of the damage caused by HMGB1.Methods Renal IRI was induced by clamping the left renal pedicle for 60 min,and the kidneys were removed at 0,3,6,or 24 h of reperfusion for detection of the HMGB1 expression by using immunohistocheistry and Western blotting.The damage was evaluated in renal function and histologic examination.Additionally,TUNEL assays were used to evaluate the apoptosis of renal cells.Results Levels of serum creatinine and blood urea nitrogen in 0 h of reperfusion group were the same as the sham group,but they were significantly increased in a time-dependent manner from 0 h to 24 h of reperfusion in mice.Immunohistocheistry demonstrated that HMGB1 was only expressed in cell nucleus in the sham-operated kidneys,which was passively released by ischemic renal cells to cytoplasm or to extracellular space as early as the time prior to reperfusion.The expression of HMGB1 was increased to a peak at 3 h of reperfusion and then decreased in a time-dependent manner to 24 h confirmed by Western blotting.The pathologic damage of IRI became worse from 0 h to 24 h of reperfusion.Additionally,the number of apoptotic cells was also significantly increased in a time-dependent manner.Conclusion The translocation of HMGB1 from the nucleus to the cytoplasm or extracellular space in the kidneys with IRI occurred earlier than the deterioration of renal function.HMGB1 may act as a crucial early inflammatory mediator during IRI.