Hippocampal neuron loss due to electric injury in rats: a stereological study

Electric injury may cause different changes from minimal damage (e.g. small burns) to severe complications up to death. Several morphological changes of the skin and the internal organs are used for the diagnosis of electrical injury. However, macroscopic findings and histological changes of the internal organs and the skin may be absent in many cases. Furthermore, neuropsychological changes including deficits of cognitive functions may be seen in survivor victims. The aim of the present study is to examine whether electric injury causes decreasing in the number of pyramidal neurons in the rat hippocampus and whether this decreasing can be demonstrated by stereological method. The rats were separated into three groups: first group, native control group; second group, the points of electrical contact were on the back skin in this group; third group, the points of electrical contact were on the temporal region in this group. The current was the usual city current (110V, 50Hz, 100A AC). On the third day, the rats were decapitated; the brains were removed, and sectioned horizontally through the hippocampus and samples chosen according to the systematic random sampling strategy. Afterwards the samples were stained by H&E and optical fractionator method, one of the unbiased stereological methods, was used to estimate the total pyramidal neuron number. The results showed that the total number of pyramidal neurons in three subdivision of the hippocampus (CA3-2 and CA1) was 242,141+/-31,167, 193,388+/-24,795 and 187,448+/-28,300 in the first, second and third groups, respectively. The differences between first and second-third groups were statistically significant (p<0.05). There was not any significant difference between the second and the third groups. In conclusion, electrocution causes loss of the pyramidal neuronal in CA3-2 and CA1 subdivisions of the rat hippocampus in this study.