Histopathological effects of intramuscular metamizole sodium on rat sciatic nerve

OBJECTIVES We investigated the histopathological effects of metamizole sodium (MS) on the sciatic nerve. MATERIALS AND METHODS This study was performed using 48 adult male Wistar albino rats. Ten groups were constituted with 6 rats in each group. MS injection into the sciatic nerve (group 1), MS injection into the muscle [group 3 (50 mg/kg, 0.4 ml) and group 5 (50 mg/kg, 0.8 ml)], MS injection into the muscle cavity in the vicinity of the sciatic nerve [group 2 (50 mg/kg, 0.4 ml) and group 4 (50 mg/kg, 0.8 ml)], normal saline injection into the muscle in the vicinity of the sciatic nerve [group 6A (0.4 ml) and 6B (0.8 ml)], subjected to injury by drilling the entire layer of nerve without injecting any drug, normal saline injection in the sciatic nerve, and control group. Nerve and muscle samples were taken 7 days after administrations. Tissue sections were stained using a hematoxylin and eosin-Luxol® fast blue stain, assessed by a histologist. RESULTS The levels of axonal degeneration of the rats in groups 1, 2, 3, 4, 5, 6A, and 8 were found to be significantly higher compared to the levels of the rats in the control group (P<0.05). Myelin degeneration of the rats in all groups was found to be significantly higher compared to myelin degeneration of the rats in the control group (P<0.05). CONCLUSION It was observed that MS could lead to injury in the sciatic nerve with a toxic effect due to diffusion.