Objective To explore the effects of dapagliflozin on D-glucose-induced apoptosis, autophagy, inflammation and oxidative damage in human glomerular podocytes through p38 mitogen-activated protein kinase (MAPK) signaling pathway.
Methods The human glomerular podocytes (HGPCs) were divided into control group (5 mmol/L D-glucose), D-glucose group (30 mmol/L D-glucose), dapagliflozin group (30 mmol/L D-glucose+50 μmol/L dapagliflozin), inhibitor group (30 mmol/L D-glucose+ 10 μmol/L p38 MAPK pathway inhibitor SB 203580), Dapagliflozin+inhibitor group (30 mmol/L D-glucose+50 μmol/L dapagliflozin+10 μmol/L SB 203580) and dapagliflozin+activator group (30 mmol/L D-glucose+50 μmol/L dapagliflozin+10 μmol/L p38 MAPK pathway activator C16-PAF). HGPCs were cultured for 24 hours in the control and D-glucose groups, and were intervened for 24 hours with corresponding drugs after cultured for 24 hours. Cell counting kit-8 (CCK-8) was used to detect the cell viability. Hoechst 33258 staining was used to detect the apoptosis rate. ELISA was used to detect the expression levels of inflammatory factors interleukin (IL) -1β, IL-6, tumor necrosis factor-α (TNF-α), malondialdehyde (MDA) and superoxide dismutase (SOD). Real-time fluorescent quantitative PCR (RT-qPCR) was used to detect the mRNA expression levels of yeast ATG6 homolog (Beclin-1) and microtubule-associated protein 1 light chain 3 (LC3) Ⅱ. Western blotting was used to detect the protein expressions of Beclin-1, LC3Ⅱ, p53, p38 MAPK and p-p38 MAPK.
Results Compared with the Control group, the cell viability was significantly decreased in the D-glucose group (P < 0.05) and was increased in the dapagliflozin group (P < 0.05). Compared with the control group, the apoptosis rate, IL-1β, IL-6, TNF-α, MDA, mRNA and protein levels of Beclin-1 and LC3 Ⅱ, protein levels of p53 and p-p38 MAPK were increased (P < 0.05), and SOD level was decreased (P < 0.05) in the D-glucose group. Compared with the D-glucose group, the apoptosis rate, IL-1β, IL-6, TNF-α, MDA, mRNA and protein levels of Beclin-1 and LC3 Ⅱ, protein levels of p53 and p-p38 MAPK were decreased in dapagliflozin group and inhibitor groups (P < 0.05), SOD level was increased (P < 0.05). Compared with the dapagliflozin group, the apoptosis rate, IL-1β, IL-6, TNF-α, MDA, mRNA and protein levels of Beclin-1 and LC3 Ⅱ, protein levels of p53 and p-p38 MAPK were further decreased in the dapagliflozin+inhibitor group (P < 0.05), SOD level was further increased (P < 0.05), and the change trend of these indicators in dapagliflozin+activator group was opposite to dapagliflozin+inhibitor group (P < 0.05).
Conclusions Dapagliflozin can inhibit the apoptosis, autophagy, inflammation and oxidative damage induced by D-glucose in HGPCs, and its mechanism may be related to the inhibition of p38 MAPK pathway signal transduction.
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