Caspase-8在大鼠生前及死后电击伤后多器官的表达

A Study on Expression of Caspase-8 in Organs of Rats after Electrical Injury at Antemortem or Postmortem

目的探讨caspase-8蛋白能否用于生前电击与死后电击的鉴别。方法建立大鼠生前与死后电流损伤模型。电击死组于死后即刻取材,生前电击伤组于电击后1h、2h、4h、8h处死;死后电击组大鼠于死后即刻、15min、30min、1h电击大鼠,采用免疫组化法检测大鼠心、肝、脾、肺、肾、骨骼肌、皮肤、脑等脏器caspase-8蛋白的表达。结果生前电击各组大鼠心、肝、肾、脑caspase-8蛋白呈强阳性表达,脾脏与骨骼肌呈阴性表达;而于死后电击各组大鼠中,仅死后即刻电击组大鼠心、肝、肺、肾、骨骼肌、脑caspase-8蛋白呈很微弱的阳性表达,其余各组各脏器均为阴性表达。结论检测各脏器caspase-8蛋白的表达情况,可以鉴别生前电击与死后电击。

Objective This study was conducted to detect the expression of caspase-8 in organs of rats after electrical injury so as to elucidate whether caspase-8 is useful in identifying electrical lesion. Methods The experiment included two parts. In the first part （the antemortem electrical injury part）, thirty-five healthy male SD rats were randomly divided into seven groups （n = 5 per group）, i.e. the group of rats subjected to instantaneous electrothanasia; the groups of rats subjected to cervical dislocation at 1 h, 2 h, 4 h, 8 h after electrical injury; the sham group and the normal control group. In the second part （the postmortem electrical injury part）, twenty-five healthy male SD rats wererandomly divided into five groups （n=5 per group）, i.e. the groups of rats electrically injured just after death, and at 15 min, 30 rain, 60 min after death; and the postmortem sham group. All experimental rats were given respectively an electric shock with two metal clamps that were connected with two poles of 220 V alternating current by clamping the rats＇ left hind limbs and right forelimbs. The rats of sham group after death were clamped but not electrified. The brain, lung, heart, liver, spleen, kidney, the muscle of electrified limb, the cutis of electrified limb of all experimental rats and those organs of control groups were dissected to detect the expression of caspase-8 by immunohistochemistry staining, and the staining intensities were assessed by image analysis system. Results In the antemortem electrical injury groups, the expression of caspase-8 was positive in brain, heart, liver and kidney; the strongest staining intensity appeard at 4 h after electrical injury and decreased at 8 h after electrical injury. In the group of rats electrically injuryed just after death, the expression of caspase-8 was faint, and the expression of caspase-8 in spleen, lung, muscle and cutis was negative in the other groups. The expression of caspase-8 in all detected organs was negative in the other rats that were electrified after death. Conclusion Caspase-8 can be regarded as an index in identifying electrical injury and distinguishing between antemortem and postmortem electrical injuryies.