烫伤后IL-6和IL-1α对大鼠外周血中性粒细胞凋亡的影响

目的:研究严重烫伤后血IL-6和IL-1α对中性粒细胞(PMN)凋亡的影响。方法:复制30%体表面积Ⅲ度烫伤大鼠模型;分离PMN,TUNEL荧光标记,流式细胞仪分析细胞凋亡;PMNcaspase3活性以荧光免疫吸附酶法测定;血清IL-6和IL-1α水平以酶联免疫法测定。结果:血清IL-6水平(μg/L)在伤后各组(3、6、12、24、48h依次分别为9.14±1.16、12.49±1.14、3.01±0.75、1.41±0.28和1.56±0.43)和IL-1α水平(ng/L)在伤后3、6、12h组(90.08±8.39、320.93±14.48和47.84±5.19)均分别显著高于伤前对照组IL-6(0.24±0.07)和IL-1α(27.65±4.86)水平(P<0.05);伤后各组PMN凋亡率(%)按时点依次为9.89±2.00、4.98±1.35、1.31±0.72、2.49±1.87和6.88±1.13显著少于伤前组13.66±3.88(P<0.05);PMNcaspase-3的活性测定结果与PMN的凋亡表现相一致。结论:大鼠烫伤后外周血PMN凋亡明显延迟;IL-6和IL-1α等细胞因子是重要的影响因素,减少细胞内caspase-3的激活可能是其机制之一。

Effects of IL-6 and IL-1α on the peripheral blood polymorphonuclear neutrophil apoptosis postburn in rats

AIM:To study the effects of IL-6 and IL-1α on the blood polymorphonuclear-neutrophils(PMN) apoptosis postburn.METHODS:Wistar rats inflicted by 30% total body surface area (TBSA) Ⅲ degree scalding were employed as the model. PMN were isolated by density gradient centrifugation using Percoll-hypaque and labeled with TdT-mediated and dUTP nick end labeling (TUNEL) and analyzed by flow cytometric analysis. The intracellular caspase-3 activation and the serum levels of IL-6 and IL-1α were analyzed by fluorometric immunosorbent enzyme assay and enzyme-linked immunosorbent assay, respectively.RESULTS:The serum IL-6 levels (μg/L) in groups of 3, 6, 12, 24 and 48 h postburn (9.14±1.16, 12.49±1.14, 3.01±0.75, 1.41±0.28 and 1.56±0.43 in turn) and IL-1α (ng/L) in groups of 3, 6, 12 h postburn (90.08±8.39, 320.93±14.48 and 47.84±5.19) were much higher than IL-6 (0.24±0.07) and IL-1α (27.65±4.86) in control group (P＜0.05), respectively. The relative proportions of apoptotic PMN(%) in groups postburn were 9.89±2.00, 4.98±1.35, 1.31±0.72, 2.49±1.87 and 6.88±1.13 in turn, which were obviously less than 13.66 ± 3.88 in the control group. The results of intracellular caspase-3 activation in PMN were observed to be consistent with the results of apoptotic PMN analysis in experimental groups.CONCLUSION:IL-6 and IL-1α are the important factors to induce PMN apoptosis delay that occurred obviously postburn. And decrease in the activity of intracellular caspase-3 of PMN may be involved in their mechanisms.