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-1ß, 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.

Puerarin protects against CCl4-induced liver fibrosis in mice: possible role of PARP-1 inhibition.

Liver fibrosis, which is the pathophysiologic process of the liver due to sustained wound healing in response to chronic liver injury, will eventually progress to cirrhosis. Puerarin, a bioactive isoflavone glucoside derived from the traditional Chinese medicine pueraria, has been reported to have many anti-inflammatory and anti-fibrosis properties. However, the detailed mechanisms are not well studied yet. This study aimed to investigate the effects of puerarin on liver function and fibrosis process in mice induced by CCl4. C57BL/6J mice were intraperitoneally injected with 10% CCl4 in olive oil(2mL/kg) with or without puerarin co-administration (100 and 200mg/kg intraperitoneally once daily) for four consecutive weeks. As indicated by the ameliorative serum hepatic enzymes and the reduced histopathologic abnormalities, the data collected showed that puerarin can protect against CCl4-induced chronic liver injury. Moreover, CCl4-induced development of fibrosis, as evidenced by increasing expression of alpha smooth muscle actin(α-SMA), collagen-1, transforming growth factor (TGF)-ß and connective tissue growth factor(CTGF) in liver, were suppressed by puerarin. Possible mechanisms related to these suppressive effects were realized by inhibition on NF-κB signaling pathway, reactive oxygen species(ROS) production and mitochondrial dysfunction in vivo. In addition, these protective inhibition mentioned above were driven by down-regulation of PARP-1 due to puerarin because puerarin can attenuate the PARP-1 expression in CCl4-damaged liver and PJ34, a kind of PARP-1 inhibitor, mimicked puerarin's protection. In conclusion, puerarin played a protective role in CCl4-induced liver fibrosis probably through inhibition of PARP-1 and subsequent attenuation of NF-κB, ROS production and mitochondrial dysfunction.