核因子κB抑制物激酶α在肾脏缺血再灌注损伤炎性反应中的作用及机制

Role of inhibitor of nuclear factor kappa B kinase alpha on renal inflammation after ischemia- reperfusion injury and its associated mechanism

目的研究核因子κB抑制物激酶α（IKKα）在肾脏缺血再灌注（IR）诱导的炎性反应中的作用及相关机制。方法用6～8周龄健康雄性C57BL／6小鼠构建肾脏IR模型，采用常规生化法检测Ser、BUN水平，HE染色法观察肾组织学改变，免疫组织化学法、Western印迹法检测肾组织IKKct、p52、RelB、IL-10、IL-18的表达。在肾实质内转入以慢病毒为载体的短发夹RNA（shRNA），抑制IKKct的表达，检测抑制后的肾功能与肾组织形态学改变以及IKKα、p52、RelB、IL-10、IL-18的表达变化。结果IR损伤组1d、3d、7d血清Scr[（29．80±2．10）μmol／L、（27．00±3．40）μmol／L、（23．00±3．70）μmol／L]和BUN[（9．47±3．50）mmol／L、（11．68±4．30）mmol／L、（13．12±2．10）mmol／L]高于假手术组Scr[（7．30_＋0．13）Ixmol／L]和BUN[（8．39_＋0．30）mmol／L]。HE染色显示，IR损伤组存在肾组织病理损害。免疫组化结果显示，Sham组小鼠肾组织抗炎因子IL—10、促炎因子IL-18均呈弱阳性表达，IR损伤后IL-10、IL-18均呈高表达，且IL-10表达呈时间依赖性上调，IL—18表达呈时间依赖性下调。IR损伤后7d内，IKKα、p52、RelB表达均上调，以第3天时最为明显。与IR损伤组相比，慢病毒载体shRNA组肾组织IR损伤第3天的IKKα、p52、RelB表达下调，IL-18表达上调，IL-10表达下调。结论肾脏IR损伤炎性反应消退过程中，NF—KB信号通路被激活，IKKα表达上调。抑制IKKα可能通过下调NF—KB旁路途径家族成员p52、RelB的活性，阻碍肾脏IR损伤炎性反应的消退。

Objective To reveal the role of inhibitor of nuclear factor kappa B kinase alpha （IKKct） in renal inflammation after renal ischemia-reperfusion （IR） injury and its potential associated mechanism. Methods Ischemia- reperfusion injury models were induced in a total of 24 healthy C57BL/6 male mice. Renal function and histological changes were estimated. The expression and site of IKKct, p52, RelB, IL-10 and IL-18 were determined by immunohistochemistry and Western blotting. After the short hairpin RNA（shRNA）targeting IKKc~ was injected into renal parenchyma, renal function and protein expressions of IKKc~, p52, RelB, IL- 10, IL- 18 were detected. Results Compared with sham-operated group[Scr（7.30±0.13） Ixmol/L, BUN （8.39±0.30） mmol/L], levels of Scr [（29.80±2.10） Ixmol/L, （27.00±3.40） Ixmol/L, （23.00±3.70） Ixmol/L] and BUN [（9.47±3.50） mmol/L, （11.68±4.30） mmol/L, （13.12±2.10） mmol/L] were higher on day 1, 3, 7 and the injury of kidney was serious in IRinjury group. Immunohistoehemieal expression of both IL- 18 and IL- 10 were increased. Markedly inereased IKKct, p52 and RelB protein expression were noted in experiments from day 1 to clay 7 during kidney recovery period, with a peak on day 3 and then decreasing toward baseline after clay 7. Compared with IR injury group, low- expression of IKKct by injection of shRNA up- regulated the expression of 1L- 18 and down-regulated the expression of IKKct, p52, RelB and IL- 10. Conclusions The NF-s：B pathway is activated and IKKct expression is up-regulated during the kidney ischemia- reperfusion injury, low-expression of IKKct may block inflammation resolution via down-regulation of alternative NF-KB pathway family members of both p52 and RelB.