LBP reduces theinflammatory injuryof kidney in septic rat and regulates the Keap1-Nrf2∕ARE signaling pathway

PURPOSE: To investigate the influence of lycium barbarum polysaccharides (LBP), a functional derivative from lycium barbarum, on septic kidney injury. METHODS: The SD male rats were randomly divided into 8 groups. The concentration of IL-1β, IL-6, IL-8, TNF-α, NF-κB and ROS, in kidney cortex homogenates after 12 h treatments were determined by enzyme-linked immunosorbent assay and ROS test kit, respectively. Morphology observation of kidney tissue was conducted with HE staining. The mRNA and protein expression levels of Nrf2, HO-1, NQO1, NF-κB, and Keap1 in kidney tissues were determined by qRT-PCR and Western blot, respectively. RESULTS: LPS treatment significantly increased the oxidative stress. After LBP treatment, the ROS content reduced significantly in a dose-depend manner. However, the levels of HO-1, NQO1 and Nrf2 as molecular elements that respond to oxidative stress were further increased. Also, administration of LBP increased the levels of NF-κB and Keap1, and decreased the levels of Nrf2 in the Keap 1-Nrf2∕ARE signaling pathway. By administrating the brusatol, the inhibition of Nrf2 enhanced the expression of NF-κB, inhibits the antioxidant responses, and further reverse the protective effect of LBP on the LPS induced septic kidney injury. CONCLUSION: Lycium barbarum polysaccharides can reduce inflammation and activate the antioxidant responses via regulating the level of pro-inflammatory cytokines and the Keap1-Nrf2/ARE signaling pathway.