| Objective: The purpose of this experiment was to investigate the mechanism of polarization on epithelium of stratum basal after electrically injured and burned skin; To quantify the morphological alteration of polarized epithelia for providing objective and quantitative indexes for forensic pathological diagnosis. Methods: The Experiment was divided into six groups, including: 380V AC, 220V AC ,220V DC, flame burned, hot metal burned and the control. Specimens from each group are dyed with hematoxylion-eosin and immunohistochemically examined with antibody against EGFR, respectively. With light microscopy (LM), circumference, long axis, short axis and long /short axis ratio of the polarized epithelia nuclei were measured and calculated,all the data were put into computer and analyzed by SAS, and measured blindly. And four specimens in each group were observed with transmissional electron microscopy (TEM) or scanning electron microscopy (SEM). Results: 1. With LM observation of all the specimens after injury, epithelia Nuclei both stratum basal and stratum spinosum were elongated and tended to align with their long axis, perpendicular to the basement membrane. Karyopyknosis and/or elongation of nuclei of stratum granulosum or lucidum were observed, and part of the elongated nuclei tended to align with their long axis, parallel to the outer surface of skin. condensation of Cytoplasm,vacuolization of nucleiand karyolysis were observed around the current mark of cathode after electrical injury by 220 V DC. 2. By measuring the circumference and the long/short axis ratio of stratum basal epithelia ,there were no significant differences among three electrically injured groups (P>0.05). The same conclusion was also obtained between the flame burned group and hot metal burned group (P>0.05). But there were obvious differences between the electrically injured groups and the burned groups (P<0.05). 3.With TEM,we observed part disappearance or condensation of cytoplasm, elongation of nuclei,chromatin close to nuclear membrane and disappearance of nucleoli in the injured epithelia except those in the current mark of cathode after 220 V DC group. In epithelia injured around cathode by 220V DC,we also observed karyolysis, fleet and equal dying nuclei and dispersion of fragment of chromatin in the nucleochyma. With SEM,there were many gaps ,holes and some fragment of cells between holes in the surface of current marks, ,Smooth surface and gaps except holes were observed in the surface of burned skin.4. Immunohistochemical staining with EGFR showed negative inthe polarized epithelia of stratum basal and spinosum of center of injured skin, but positive and uniform staining in the periphery of injured skin. Conclusion: 1. Polarization of epithelia in the periphery of current mark was resulted from thermal effect rather than electric field. 2. The circumference and the long/short axis ratio of polarized epithelia nuclei in periphery of injured skin may be used to differentiate low voltage electrical injury from burn injury. Within the low-voltage range,those indexes can not used to determine the voltage, alternating or direct current that caused electrical injury. 3. We observed condensation of cytoplasm,karyolysis, vacuolization of nuclei, or condensation of chromatin and brightness around its periphery by LM,and condensation of cytoplasm, karyolysis, dispersion of chromatin fragment in the nucleochyma around the current mark of cathode by TEM, which can be used as a diagnosis index for DC injury. Holes in the surface of injuried skin may be used as one of the indexes to differentiate the electrical injury from the burn. |
PDF Full Text Request