Quercetin Ameliorates CFA-Induced Chronic Inflammatory Hyperalgesia via Modulation of ROS-Mediated ERK1/2 Signaling and Inhibition of Spinal Glial Activation In Vivo

AbstractImpact of reactive oxygen species (ROS) in development of hyperalgesia has recently motivated scientists to focus on ROS as novel target of anti-hyperalgesic interventions. Studies have indicated the usefulness of ROS scavengers and exogenous antioxidants as anti-nociceptive agents in animal models of neuropathic and inflammatory hyperalgesia. In present study, we suggest the anti-hyperalgesic potential of the dietary antioxidant quercetin on chronic inflammatory hyperalgesia induced by Complete Freund ’s Adjuvant (CFA). Three doses of quercetin (25, 50 and 75 mg/kg body weight) for consecutive 7 days were used for the study. Thermal hyperalgesia was assessed by paw withdrawal latency (PWL) test and inflammation was checked in terms of changes in paw edema. The insight of molecular signaling during chronic hyperalgesia was analyzed by TNF-α–TNFR1–ERK1/2 pathway in relation to change in ROS level in DRG and spinal cord. CFA-induced hyperalgesia was confirmed by decreased PWL and increased c-Fos activity in dorsal horn of spinal cord, determined by immunohistochemical analysis. It wa s characterized with elevated level of ROS and TNF-α estimated by ELISA. The activation of ERK1/2 and NF-κB in DRG and spinal cord and over-expression of TNFR1 in DRG were analyzed by Western blotting. Up-regulation of Iba1 and GFAP indicates glial activation in spinal cord. Expression of GFAP and its co-localization with NF-κB were examined by immunofluorescence. All the molec...
Source: NeuroMolecular Medicine - Category: Neurology Source Type: research