Analgesic effects of Terminalia Chebula is mediated by suppression of brain protein expression of NGF and NF-κB and oxidative markers following neuropathic pain in rats

Abstract

Background: Due to the complications related to the use of the current pharmacological approach for relief of neuropathic pain, searching for effective compound with less complication is need of present era. Since, the pathophysiology mechanism of neuropathic pain is related to excessive inflammation in nervous system. Hence, the present study focuses on whether the potential analgesic effects of Terminalia Chebula (TC) extract is mediated by the changes of brain protein expression of nerve growth factor (NGF) and nuclear factor-kappa B (NF-κB) in a rat model of sciatic nerve chronic constriction injury (CCI).Method and Results: Neuropathic pain induced by left sciatic nerve CCI. Male wistar rats assigned into sham, CCI, and CCI+TC (40mg/kg) groups. Animals received normal saline (1 ml) or aqueous-alcoholic extract of TC (40 mg/kg) for 30 days via gavage needles once a day. Cold allodynia and anxiety-like behaviors examined on one day before CCI surgery (day -1) and also on days 2, 7, 14 and 30 following CCI. We also assessed TC extract effects on oxidative stress markers on day 30 following CCI. Furthermore, western blot study performed on day 30 following CCI for evaluation of TC extract effects on protein expression of NGF and NF-κB of the brain. Orally gavage of TC extract significantly decreased cold allodynia on days 2 and 14 following CCI. Additionally, CCI model of chronic pain significantly increased protein expression of NGF and NF-κB of the brain on day 30 following CCI. Furthermore, TC extract significantly decreased protein expression of NGF and NF-κB of the brain. The TC extract significantly increased brain glutathione (GSH) content and decreased malondialdehyde (MDA) content. Conclusions: It is suggested that analgesic effects of TC extract is mediated by suppression of brain NGF, NF-κB, and also its antioxidant activity in the brain following neuropathic pain in rats.