Oral cannabinoid formulation elevates sensory nerve conduction velocity and mitigates oxidative stress to alleviate neuropathic pain in rats.

Background and aim: Use of potent painkillers like opiates are limited by their abuse potential and adverse physiological effects necessitating new therapeutics for pain management. This study assessed the efficacy of oral cannabinoid formulations (F1-F4) in alleviating chronic neuropathic pain (CP) and investigated their mechanisms through thermal algesia, inflammatory and oxidative stress biomarkers, and sensory nerve conduction velocity (SNCV).

Experimental procedures: A 21-day rat model of chronic constriction injury (CCI) of the sciatic nerve was used to evaluate the effects of oral cannabinoid formulations (F1: 500 mg, F2: 1000 mg, F3: 2000 mg, F4: 3000 mg) in MCT oil, with pregabalin as the reference. Male Wistar rats (35) were divided equally into seven groups, with all except the Sham group undergoing sciatic nerve ligation and receiving different formulations.On day 22, behavioral (hot plate, tail flick) and electrophysiological (sensory nerve conduction velocity, SNCV) assessments were performed. SNCV was also measured in the presence of CB1 and CB2 receptor antagonists. Additionally, blood-based markers of inflammation (TNF-α) and oxidative stress (MDA, GSH and CAT) were analysed.

Results and conclusions: The vehicle group exhibited significant hyperalgesia (p <0.005), reduced sensory nerve conduction velocity (SNCV) (p <0.005) and elevated MDA and TNF-α levels, along with decreased GSH and CAT levels in both serum and sciatic nerve tissue.Among the formulations, F2 significantly improved pain latency and SNCV (p <0.005) compared to the vehicle group and outperformed F1, F3, F4 and pregabalin (p <0.05). Its effects were mediated through CB1 and CB2 receptor agonism while simultaneously reducing oxidative stress and inflammation, highlighting its potential as a promising candidate for neuropathic pain management.