Attenuation of inflammatory pain by puerarin in animal model of inflammation through inhibition of pro-inflammatory mediators.

In the current study, the puerarin was investigated for both acute Carrageenan and chronic CFA-induced inflammatory pain models. The Puerarin treatment significantly attenuated (P < 0.001) the mechanical hyperalgesia and mechanical allodynia in both Carrageenan and CFA-induced hyperalgesia. The Puerarin treatment also remarkably reduced (p < 0.001) the thermal hyperalgesic responses in both acute Carrageenan as well as chronic CFA-induced models. Furthermore, the Puerarin administration was also associated with significant inhibition of (p < 0.001) paw edema in both Carrageenan and CFA-induced models. The inflammatory mediators such as IL-1β, IL-6, TNF-α and vascular endothelial growth factor (VEGF) are significantly enhanced during inflammatory conditions, however, the Puerarin administration significantly altered (P < 0.001) the mRNA expression levels of these mediators. Additionally, the Puerarin treatment also significantly enhanced (P < 0.001) the mRNA expressions levels of the anti-oxidant enzymes such as Nrf2, HO-1 and SOD2. The Puerarin treatment is associated with significant (P < 0.001) inhibition of the acetic acid-induced Evans blue vascular permeability. Moreover, the concentration of Puerarin in various tissues was analyzed using High-performance liquid chromatography (HPLC) and the results showed that the Puerarin was significantly distributed towards the peripheral tissues such as liver and kidney and less distributed towards the brain.