右美托咪定对大鼠离体肺缺血-再灌注损伤时RIPK3/MLKL介导程序性坏死的影响

Effects of dexmedetomidine on RIPK3/MLKL-mediated pulmonary necroptosis during isolated lung ischemia-reperfusion injury in rats

目的评价右美托咪定对大鼠离体肺缺血-再灌注损伤(LIRI)时受体相互作用蛋白激酶3(RIPK3)/混合系列蛋白酶样结构域(MLKL)介导的肺组织细胞程序性坏死的影响。方法成年雄性SD大鼠72只,采用随机数字表法随机分成三组(n=24):缺血-再灌注损伤组(IR组)、右美托咪定组(DEX组)和对照组(C组)。IR组采用IL-2型离体肺灌流系统建立大鼠离体LIRI模型;DEX组在复灌开始时于灌流液中加入右美托咪定10 nmol/L;C组只通气和灌流。测定大鼠肺组织湿/干重比(W/D),光镜下观察肺组织病理学并测定肺泡损伤率(IAR)。测定灌流液中超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量。Western blot法分别检测肺组织中RIPK3和MLKL蛋白含量。结果与C组比较,IR组和DEX组肺组织W/D、IAR和灌流液中MDA含量均明显升高(P<0.05),而灌流液中SOD活性均明显降低(P<0.05)。与IR组比较,DEX组肺组织W/D、IAR和灌流液中MDA含量均明显降低(P<0.05),而灌流液中SOD活性明显升高(P<0.05)。光镜显示IR组肺组织形态学结构发生明显损伤,而DEX组则明显减轻。与C组比较,IR组和DEX组肺组织RIPK3和MLKL蛋白含量均明显升高(P<0.05);与IR组比较,DEX组肺组织RIPK3和MLKL蛋白含量均明显降低(P<0.05)。结论右美托咪定可通过抑制RIPK3/MLKL介导的肺组织细胞程序性坏死来减轻大鼠离体肺缺血-再灌注损伤。

Objective To investigate the dexmedetomidine on receptor-interacting protein kinase 3(RIPK3)/mixed protein expression of the protease-like domain(MLKL)-mediated pulmonary necroptosis during isolated lung ischemia-reperfusion injury(LIRI) in rats. Methods Seventy-two male Sprague-Dawley rats were randomly divided into three groups(n = 24 each) by a random number table: control group(group C), ischemia/reperfusion group(group IR) and dexmedetomidine group(group DEX). The rat model of isolated LIRI was established by using IL-2 ex-vivo lung perfusion system in group IR, while the islolated lung only received ventilation and perfusion in group C. In group DEX, dexmedetomidine 10 nmol/L was administrated into perfusion fluid at the beginning of reperfusion. Lung wet/dry weight ratio(W/D) was measured. Morphological changes of the lungs were observed under light microscope. The activity of superoxide dismutase(SOD) and the content of malondialdehyde(MDA) in the perfusion fluid were determined. Western blot was used to detect the content of RIPK3 and MLKL in lung tissue. Results Compared with group C, W/D, IAR of lung tissue and the content of MDA in the perfusion fluid were increased(P < 0.05), while the activity of SOD in the perfusate was decreased in group IR and group DEX(P < 0.05). Compared with group IR, W/D, IAR of lung tissue and the content of MDA in the perfusion fluid were decreased(P < 0.05), while the activity of SOD in the perfusate was increased in group DEX(P < 0.05). Light microscopy showed that the morphological structure of the lung tissue were significantly damaged in group IR, while was significantly relieved in group DEX. Compared with group C, the content of RIPK3 and MLKL protein in lung tissue were increased in group IR and group DEX(P < 0.05). Compared with group IR, the content of RIPK3 and MLKL protein in lung tissue of group DEX were decreased in group DEX(P < 0.05). Conclusion Dexmedetomidine may reduce LIRI in rat isolated lungs via inhibiting RIPK3/MLKL-mediated pulmonary necroptosis.