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

Abstract

Abstract Background The sensation of pain as a pathological entity has always been discussed. The current study was conducted to determine the analgesic effect of gamma-linolenic acid (GLA) in the formalin test. Methods The formalin was injected into the right hind paw in rats. The 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 interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were measured in the skin. Results The attenuation of nociceptive response persisted after GLA injection in formalin treated rats. Formalin injection also enhanced the levels of cytokines, including TNF-α and IL-1β in the hind paw, which could be repressed by GLA. Also, western blot analysis showed that formalin increase c-Fos protein in the spinal cord, which could be suppressed by GLA. The 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. Conclusion Our results demonstrated that pretreatment, with GLA, produced antinociceptive effects in the formalin test and may be effective for pain relief.