The Mechanism Of PPARα Agonist Fenofibrate Inhibits Mesangial Cells Proliferation And Extracellular Matrix Induced By High Glucose

Objective: To observe the effect of peroxisome proliferator activated receptor alpha(PPARα)agonist fenofibrate on cell proliferation and extracellular matrix (ECM) induced by high glucose in mesangial cells, and detective the molecule mechanism of PPARαon diabetic nephropathy in vitro.Methods: We intervene the glumeruler mesangial cells (MCs) with high glucose cultued in vitro. The MCs were divided into follow groups: the control group , the group of MCs cultured with high glucose , and five other groups exposed in high glucose and different concentrations of fenofibrate or MK886(a PPARαantagonist). PPARα-induced transcriptional activity was evaluated by transient transfection of an expression vector containing four copies of a consensus PPAR response element (PPRE) placed upstream from the PGL2-basic luciferase reporter (p4xPPRE-Luc), Dual Luciferase Reporter Gene assay the activity of PPARα. Then we use RT-PCR and Western blot to detect the expression of PPARαmRNA and protein in different groups. MTT assay was used to determine the effect of fenofibrate on cell proferation. Flow cytometry was employed to analyze cell cycle. The level of TERT mRNA and fibronectin mRNA was detected by RT-PCR. Western Blot and immunofluorescence were used to measure the expression ofα-SMA, Collagen-IV, P-AKT and P-ERK1/2 protein with different groups.Results:○1 Compare with the high glucose group, increased luciferase activity was found in 24 hours of exposure to high glucose and fenofibrate with a dose independent , while it is reversed by MK886.○2 Compare with the control group, PPARαmRNA and protein was up regulation induced by high glucose (P<0.05), compared with high glucose group, the level that intervened with fenofibrate was increased with a dose independent (P<0.05), while the groups of MK886 was decreased (P<0.05).○3 The proliferation of MCs at different time after incubating with different concentrations of fenofibrate was statistically different from that of controls (P<0.05). The cell cycle was arrested in G1/S phase. The percentage of G0/G1 phase cells gradually increased with the rising concentrations of fenofibrate (P<0.05), while the proportion of S phase cells were reduced (P<0.05).○4Fenofibrate can dramatically suppress high-glucose mediated the expression of fibronectin mRNA andα-SMA, Col-IV protein, such expression in the MK886 groups was reverse.○5 We found the phosphorylation of AKT and ERK1/2 in high glucose was increased, that was down regulated by fenofibrate (P<0.05).Conclusion: Fenofibrate inhibited mesangial cell proliferation and the expression of fibronectin,α-SMA and Collagen-IV which may play a renoprotective role on diabetic nephropathy. The molecule mechanism may refer to the cell signal pathway of PI3K-AKT and ERK1/2 after PPARαactivation.