Long-term effect of a single dose of sulfur mustard on nerve conduction velocity and electromyography pattern in rat hindlimb.

Objective: Biological effects of sulfur mustard (SM) on various systems have been investigated in both humans and animals. However, few studies are available on the effect of SM on the peripheral nervous system. In the present study, long-term effects of a single dose of SM on nerve conduction velocity and electromyography (EMG) pattern is evaluated in hindlimb of adult male rats.
Methods: SM poisoning was induced by two means: subcutaneous injection of 1 and 3.5 mg/kg SM in two experimental groups (1 and 2) and cutaneous application of 8 and 13 mg/kg SM in groups 3 and 4. Sham and control groups received SM vehicle, isopropyl alcohol, and nothing, respectively. Electrophysiological assessments were performed after 26 weeks as follows: sciatic nerve conduction study that included measuring, amplitude, duration, and latency of M-wave, F-wave latency, and EMG study in resting and minimal contraction states.
Results: Results indicate that sciatic nerve conduction velocity did not significantly change in any experimental groups. However, resting EMG records showed some abnormalities very similar to positive sharp waves and fasciculation reported in humans. These abnormalities were observed in 6 of 36 intoxicated rats.
Conclusions: Although the present data are in favor of axonal degeneration, to rule out the possibility of other types of degeneration, additional thorough studies at ultrastructural level are suggested.