[Inhibitory effect of polydatin on expression of toll-like receptor 4 in ischemia-reperfusion injured NRK-52E cells].

Polydatin is a monocrystaline compound isolated from Polygonum cuspidatum Sieb. et Zucc. (Polygonaceae) with biological properties, such as anti-inflammation, anti-oxidative and nephroprotective effects. Increasing number of studies have demonstrated the protective effect of polydatin on renal ischemia reperfusion injury. However, the possible mechanisms of this protection are not fully elucidated. This study aimed to investigate the effect of polydatin on ischemia-reperfusion induced expression of toll-like receptor4 (TLR4) in rat renal tubular epithelia cells (NRK-52E), and analyze the mechanism of polydatin on TLR4 signal pathway. The cultured NRK-52E cells were incubated in three gas incubators for a period of 6 h at hypoxia and 24h at reoxygenation to simulate the ischemia-reperfusion injury in vitro. TLR4 mRNA level was analyzed by real-time-PCR, and the protein expression of TLR4 and NF-κB by Western blotting, while TNF-α and IL-1β proteins expressions were detected by ELISA. Polydatin downregulated I/R induced mRNA and protein expressions of TLR4, and decreased the protein expression of NF-κB, TNF-α and IL-1β. The TLR4 blocker partially antagonized the effect of I/R on NF-κB signaling, and such inhibitory effect was markedly enhanced by polydatin. In the present study, polydatin protects NRK-52E cells from I/R injury possibly by relieving the inflammatory response through regulation of TLR4/NF-κB signaling pathway.