Pterostilbene Inhibits Inflammation in Rat Nucleus Pulposus by Promoting the Nuclear Translocation of Nrf2

Abstract: Pterostilbene (PTE) is a natural drug with the ability of inhibiting inflammation and oxidative stress. However， the effect of PTE on the inflammation in nucleus pulposus cells (NPCs) and the related mechanism have not been reported. In this study， primary NPCs of SD rats were cultured， and the cell viability was analyzed by the CCK-8 analysis. ELISA， Real-time PCR and Griess test were used to detect the effect of PTE on the inflammation induced by IL-1β. Western blot， immunofluorescence， siRNA for nuclear factor erythroid 2-related factor 2 (Nrf2) were used to analyze the role of Nrf2 in the inhibitory role of PTE on the inflammation. The results showed that the treatment of 20 μmol/L PTE for 24 h had no effect on cellular viability. PTE could inhibit the production of nitric oxide (NO) and prostaglandin E2 (PGE2) induced by IL-1β， as well as the mRNA level of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) (P<0.05). The result of Western blot showed that PTE increased the level of nuclear Nrf2 protein but decreased the level of cytoplasmic Nrf2 protein (P<0.05). The study by immunofluorescence showed that cytoplasmic Nrf2 was transferred into the nuclei. After transfection of Nrf2 siRNA and validation by Western blot， the inhibitory effect of PTE on those inflammatory mediators was attenuated (P<0.05). These results indicated that PTE inhibits the inflammation induced by IL-1β in NPCs through promoting the nuclear translocation of Nrf2.

CSTR: 32200.14.cjcb.2016.10.0005