Pyridoxine induced neuropathy by subcutaneous administration in dogs

To construct a sensory neuropathy model, excess pyridoxine (150 mg/kg s.i.d.) was injected subcutaneously in dogs over a period of 7 days. During the administrations period, the dogs experienced body weight reduction and proprioceptive loss involving the hindquarters. After pyridoxine administration was completed, electrophysiological recordings showed that the M wave remained at a normal state, but the H-reflex of the treated dogs disappeared at 7 days. The dorsal funiculus of L₄ was disrupted irregularly in the axons and myelin with vacuolation. The dorsal root ganglia of L₄, and sciatic and tibial nerves showed degenerative changes and vacuolation. However, the lateral and ventral funiculi of L₄ showed a normal histopathologic pattern. Although this subcutaneous administration method did not cause systemic toxicity and effectively induced sensory neuropathy, this study confirmed the possibility of producing a pyridoxine-induced sensory neuropathy model in dogs with short-term administration.