[A study on expression of caspase-8 in organs of rats after electrical injury at antemortem or postmortem].

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 were randomly divided into five groups (n=5 per group), i.e. the groups of rats electrically injured just after death, and at 15 min, 30 min, 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.