ELISA and real-time PCR assays were performed to determine levels of Nrf2 in DN patients and healthy controls (A,B). SV40 MES 13 cells were transfected with HMGB1 siRNA or scramble siRNA and stimulated with high glucose (25 mM). Western blot and immunofluorescence staining were performed to detect expression of HMGB1 in the cytoplasm and nucleus in glucose-treated SV40 MES 13 cells (C,D). (E) The protein levels of Nrf2, TLR4, and NF-κB p65 were determined using Western blot. (F,G) Relative mRNA levels of Nrf2 and its downstream targets, including HO-1, NQO-1, GCLC and GCLM, were detected using real-time PCR in SV40 MES 13 cells after siRNA treatment. *P<0.05, **P<0.01, ***P<0.001, compared with control. #P<0.05, ##P<0.01, compared with HG group.