ANTI-NOCICEPTIVE EFFECTS OF A STANDARDIZED EXTRACT OF ZINGIBER OF- FICINALE ROSCOE IN A MICE MODEL OF NEUROPATHIC PAIN

Peripheral neuropathic pain is a severe chronic pain condition characterised by damage on the so- matosensory system. Hyperalgesia and allodynia are the most representative symptoms of this unsatisfying. Zingiber officinale Roscoe is known in Western medicine mostly for its use in gastric complaints, but it has been widely used in Chinese and Indian traditional medicine for treating a variety of conditions, including pain. Therefore, we investigated the possible analgesic effect of a standardized extract of Z. officinale rhizome (Ginger EXT; containing 24.73% total gingerols and 3.03% total shogaols) in a mice model of trauma-induced peripheral mononeuropathy, provoked by spared nerve injury (SNI). CD1 male mice exposed to SNI developed a more promi- nent mechanical and thermal hypersensitivity compared with not operated mice. 7 days after sur- gery, mice were treated with Ginger EXT at 100, 200, 400 (mg/kg), by oral administration. Ginger EXT 200 mg/kg ameliorated allodynia and thermal hyperalgesia in SNI mice, with a prolonged effect that was still significant 120 min after the administration. Western blotting was used to char- acterize the possible mechanism of action. SNI mice showed an increase in activated MAPK (ERK, JNK, p38) protein levels in the spinal cord. Ginger EXT 200 (mg/kg) completely reversed the increased expression of p-ERK42/44. A tendency to reduce JNK1 activation was also observed. These data highlight the possible role of Z. officinale as a possible analgesic drug in the management of neuropathic pain.