Attenuating effect of standardized fruit extract of punica granatum L in rat model of tibial and sural nerve transection induced neuropathic pain

BACKGROUND Injury to a nerve is the most common reason of acquired peripheral neuropathy. Therefore, searching for effective substance to recover of nerve after injury is need of present era. The current study investigates the protective potential of Standardized Fruit Extract of Punica granatum L (PFE) [Ellagic acid (41.6%), Punicalagins (10%), Granatin (5.1%)] in Tibial & Sural Nerve Transection (TST) induced neuropathic pain in rats. METHODS TST was performed by sectioning tibial and sural nerve portions of the sciatic nerve and leaving the common peroneal nerve intact. Acetone drop, pin-prick, hot plate, paint brush & Walking Track tests were performed to assess cold allodynia; mechanical heat, hyperalgesia and dynamic mechanical allodynia & tibial functional index respectively. The levels of TNF-α, TBARS, GSH and Nitrite were measured in the sciatic nerve as an index of inflammation & oxidative stress. RESULTS TST led to significant development of cold allodynia; mechanical and heat hyperalgesia; dynamic mechanical allodynia; functional deficit in walking along with rise in the levels of TBARS, TNF-α, GSH and Nitrite. Administrations of PFE (100 & 300 mg/kg oral), significantly attenuate TST induced behavioral & biochemical changes. Pretreatments of BADGE (120 mg/kg IP) a PPAR-γ antagonist and nitric oxide precursor L-arginine (100 mg/kg IP) abolished the protective effect of PFE. Whereas, pretreatment of L-NAME (5 mg/kg IP) a NOS inhibitor significantly potentiated PFE's protective effect of PFE. CONCLUSION PFE shown to have attenuating effect in TST induced neuropathic pain which may be attributed to potential PPAR-gamma agonistic activity, nitric oxide inhibitory, anti-inflammatory and anti oxidative actions.