The sesquiterpene lactone-enriched extract from Linderae Radix ameliorated high glucose-induced renal tubular epithelial injury via mediating PPARγ/Nrf2 pathway

Diabetic nephropathy (DN) is a common microvascular complication with limited effective interventions in diabetic patients. Linderae Radix is a traditional herbal tonic used to treat various kidney and metabolic diseases. In this study, we evaluated the efficacy and mechanism of the main bioactive components, sesquiterpene lactones in L. Radix (SLR), on DN. The results showed that treatment with SLR reduced the levels of apoptotic rates, ROS, TNF-α, IL-6, and IL-1β, but increased the activities of SOD and GSH-Px in high glucose-treated HK2 cells. Furthermore, SLR improved renal dysfunction but increased the activities of SOD and GSH-Px in the renal tissues of DN mice. Mechanistically, SLR upregulated the expressions of Nrf2 and HO-1 but downregulated NF-κB in high glucose-treated HK2 cells by targeting PPAR, which could be reversed by the PPARγ inhibitor SR202. Therefore, SLR improved DN by reducing oxidative stress, cell apoptosis, and inflammatory response through activating PPARγ/Nrf2 pathway.