Neuropathologic and morphometric effects of aminoguanidine on rat nerves

Aminoguanidine prevents some pathophysiologic changes typical of streptozocin diabetes and, therefore, might be efficacious in prevention or treatment of human diabetic polyneuropathy. In order to evaluate the possible toxicity of aminoguanidine on peripheral nerves, Sprague-Dawley rats received aminoguanidine intraperitoneally in dosages of 0, 50, 100, and 300 mg/kg per day for 3 months. Only rats receiving the highest dosages developed acute and chronic behavioral changes and had decreased weight gain. Minor hepatic dysfunction also was observed in this group. Teased-fiber abnormalities were not significantly more frequent in the highest dosage group than in controls. Likewise, a significant morphometric abnormality was not found for the peroneal nerve. Mild changes were found in the highest dosage group compared to the control group in the sural nerve (increased fiber density, decreased myelin area). We interpret the small morphometric differences for the sural nerve as due to maldevelopment. We found no evidence that aminoguanidine at a high dosage (300 mg/kg per day) caused fiber degeneration or demyelination.