The Effect of Gamma Linoleic Acid on the Expression of c-Fos and Inflammatory Factors on the Formalin-Induced Pain

Abstract

Abstract Introduction: The sensation of pain as a pathological entity has always been discussed. The current study was conducted to determine the analgesic effect of gamma linoleic acid (GLA) in the formalin test. Materials and methods: Formalin was injected into the right hind paw in rats. Pain behaviors were determined as a numerical score for 60 minutes after the injection of formalin. The spinal cord was removed to evaluate the protein expression of C-Fos. Also, the levels of TNF-α and IL-1β were measured in the skin where formalin was injected. Results: Doses of 100 and 150 mg/kg of GLA could reduce pain perception in the acute phase of the formalin test. Also, GLA 100 and 150 mg/kg reduction of TNF-α and IL-1β induced by formalin compared with the control group. There was elevated c-Fos protein observed in the spinal cord after formalin injection in GLA 100 and 150 mg/kg compared with the control group. Conclusion: Molecular analysis targeting c-Fos and inflammatory cytokines such as TNF-α and IL-1b also showed an effect of GLA, which matched the results of the behavioral data analysis. These results demonstrated that pretreatment, with GLA, produced antinociceptive effects in the formalin test and may be effective for pain relief.