F-wave, sensory potential and nociceptive response in a rat model of streptozotocin-induced diabetic neuropathy

Abstract

Introduction: F-wave, sensory potentials and nociceptive response to painful stimulus are neurophysiological tests used to address the neuropathic condition in experimental models performed in laboratory animals.

Objective: To demonstrate the effectiveness of a new dosing schedule in a rat model of streptozotocin-induced diabetic neuropathy.

Methods: Streptozotocin was administered to adult Wistar rats at doses of 30 mg/kg per day on alternate days (Monday, Wednesday and Friday) for one week. Glycemic levels and body weight were measured before streptozotocin treatment and weekly throughout the experimental period (6 weeks). The F wave was recorded in the foot muscles with ankle stimulation. The sensory potential of the caudal nerves was recorded. The reaction time to a thermal nociceptive stimulus was examined in the hot plate test.

Results: In animals treated with streptozotocin sustained levels of hyperglycemia and progressive reduction of body weight revealed diabetic neuropathic condition, also F-wave conformation and its parameters (amplitude, integral index and persistence) were severely reduced, as well as velocity conduction for sensory potential (p˂0.05), reaction time increased significantly (p˂ 0.05).

Conclusions: Neurophysiological tests were effective in demonstrating that the dosing schedule used is capable of developing peripheral neuropathy over a six-week period. The changes in the F wave were particularly relevant and suggest that, in parallel with peripheral sensory transmission, evidenced by sensory potential and reaction time, there is neuropathic involvement of the central and/or proximal portions of the motor fibers.