The objective of this study was to determine by observing nerves and muscle tissues to what degree tissue damage progressed after electrical bums. 30 rats were divided into 6 subgroups by post-bum periods with 5 rats in each group: one-day, two-day, four-day, seven-day, fourteen-day, and thirty-day groups.
Light microscopic studies were done in each group to observe the change of the nerves and muscles, and electron microscopical studies were done also in the one-day, two-day, four-day, seven-day, fourteen-day, thirth-day groups for detailed changes of nerve tissues.
The results were as follows:
1. Under the light microscope, nerves and muscles were compared in relation to progression of tissue damage. Nerve changes were the following: In the one-day group edema and vacuolization were seen in the nerve tissue. In the two-day group, necrotic change progressed to 0.75-1 cm in length. After the four-day group, there was no progression of the nerve necrotic loss.
The muscular changes were remarkable: The muscles showed immediate necrosis. In the two-day groups, there was rapid progression of the necrosis to a length of 2.5-3.0cm. In the four-day group, there was slow progression of the necrosis, when compared to the two-day group, and the necrotic muscle length was 3.0-3.5cm. After the four-day group, there was no progression.
2. Under the electron microscope, the changes of the nerves were the following: In the one-day group, the myelin sheath was disorganized from the lamellar structure. The axon was vacuolized and nerve cells showed mitochondrial swelling and many lysosomal bodies. In the two and four-day groups, the myelin sheath was fragmented and lost lamellar structure. In another groups, after four-day group, the nerves that were located at more than 1 cm from the center showed mild axonal vacuolization and less severe damage on myelin sheath than previous groups.
These findings suggested that the damage to the nerves was lesser than that it the muscles, and that electric bums were not progressive after the fourth day.
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