摘要Background To determine the binding activity of nuclear factor-KB (NF-κB) and the transcription of transforming growth factor-βl (TGF-β1) induced by oxidized Iow density lipoprotein (Ox-LDL) in rat mesangial cells and to elucidate the mechanism of renal injury of Ox-LDL Methods NF-κB binding activity was measured by gel shift assay in mesangial cells with or without inducement of Ox-LDL. Protein kinase inhibitors and activtors were then used to determine the signal transduction pathways. In this course IκB protein expression was analyzed by Westerm blot assay. TGF-β1 mRNA was measured in mesangial cells exposed to Ox-LDL by RT-PCR assay. TGF-β1 promoter from -1551 to+57 were constructed into a pGL3-Basic vector with a luciferase reporting gene. A putative binding site of NF-KB was mutated. The wild and mutant promoters activity was analyzed by transfection into mesangial cells. Results NF-KB was activated by Ox-LDL persistently and rebounded in the early period. Ox-LDL induced NF-κB activation in a dose dependent way. It also induced IκB degradation in 2 hours and resumed to normal levels. NF-κB activation was not alleviated by inhibitors of protein kinase A ( PKA), extracellular signal-regulated kinase (ERK), and p38 MAP kinase (p38MAPK). Inhibitors of protein kinase C (PKC) and proteinsome inhibited the enhancement of NF-KB binding activity. Ox-LDL induced the transcription of TGF-βI in a time and dose dependent manner. Mutation of the putative binding site of NF-κB reduced the activity of TGF-β1 promoter. Conclusion Ox-LDL induced activation of NF-KB persistently. It was probably regulated by the degradation of IκB mediated by PKC pathway. NF-KB may be involved in the enhancement of TGF-βI induced by Ox-LDL in rat mesangial cells.