挤压综合征对大鼠心肌细胞损伤的作用机制

Mechanism of crush syndrome on myocardial cell injury in rats

目的研究挤压伤致股骨干骨折引起的挤压综合征(CS)对大鼠心肌细胞损伤的作用机制。方法将32只SD雄性大鼠随机分为对照组、CS后再灌注0 h组(CS-0组),CS后再灌注12 h组(CS-12组)、CS后再灌注24 h组(CS-24组),每组8只。CS组采用自制挤压器制作大鼠CS模型,利用4%多聚甲醛灌注0、12、24 h。采用苏木伊红染色法观察各组大鼠心肌组织形态,TUNEL法检测凋亡心肌细胞情况,并采用试剂盒检测心肌匀浆液中丙二醛(MDA)、超氧化物歧化酶(SOD)、乳糖脱氢酶(LDH)、白介素-6(IL-6)、白介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)水平及活性,并通过Western blot检测心肌细胞中半胱氨酸蛋白酶-3(Caspase-3)、Bax、Bcl-2、核转录因子-κB(NF-κB)蛋白表达情况。结果与对照组相比,CS模型组大鼠心肌组织均有不同程度形态损伤,表现为心肌纤维断裂、排序紊乱、间质水肿和炎症细胞浸润;与对照组相比,CS-0组、CS-12组、CS-24组心肌细胞凋亡率、Caspase-3、Bax蛋白表达水平均显著升高(P<0.05),Bcl-2蛋白表达水平显著降低(P<0.05);与对照组相比,CS-0组、CS-12组、CS-24组心肌匀浆中MDA、LDH、IL-6、IL-1β、TNF-α水平及P65蛋白磷酸化均显著升高(P<0.05),SOD活性显著降低(P<0.05)。结论 CS后再灌注可能通过激活NF-κB途径抑制氧化应激并诱导炎症反应从而损伤大鼠心肌细胞。

Objective To investigate the mechanism of crush syndrome(CS)induced by crush injury on myocardial cells in rats.Methods Thirty two male Sprague Dawley(SD)rats were randomly divided into control group,CS-0 group,CS-12 group and CS-24 group with 8 rats in each group.CS model was made by self-made extruder and perfused with 4%paraformaldehyde for 0,12 and 24 h.The morphological changes of myocardial tissue were observed by hematoxylin staining.The apoptosis of cardiomyocytes was detected by terminal dexynucleotide transferase-mediated nick end labeling(TUNEL).The levels and activities of malondialdehyde(MDA),superoxide dismutase(SOD),lactose dehydrogenase(LDH),in-terleukin-6(IL-6),interleukin-1 p(IL-1β),tumor necrosis factor-α(TNF-α)in myocardial homogenate were detected by enzyme-linked immunosorbent assay(ELISA).The expressions of Caspase-3,Bax,Bcl-2 and necrosis factor-kB(NF-κB)were detected by Western blot.Results Compared with the control group,the myocardial tissue of CS model group had different degrees of morphological damage;compared with the control group,the apoptosis rate,Caspase-3 and Bax protein expression levels of CS-0 group,CS-12 group and CS-24 group were significantly increased(P<0.05),and the expression level of Bcl-2 protein was significantly decreased(P<0.05);compared with the control group,the levels of MDA,LDH,IL-6,IL-lp,TNF-o.and p65 protein phosphorylation in the myocardial homogenate of CS-0 group,CS-12 group and CS-24 group were significantly increased(P<0.05),and SOD activity was significantly decreased(P<0.05).Conclusions CS may inhibit oxidative stress and induce inflammatory reaction by activating NF-κB pathway,thus damaging myocardial cells in rats.