Pioglitazone inhibits the expression of nicotinamide adenine dinucleotide phosphate oxidase and p38 mitogen-activated protein kinase in rat mesangial cells.
BACKGROUND
Oxidative Stress and p38 mitogen-activated protein kinase (p38MAPK) play a vital role in renal fibrosis. Pioglitazone can protect kidney but the underlying mechanisms are less clear. The purpose of this study was to investigate the effect of pioglitazone on oxidative stress and whether the severity of oxidative stress was associated with the phosphorylation level of p38MAPK.


METHODS
Rat mesangial cells were cultured and randomly assigned to control group, high glucose group and pioglitazone group. After 48-hour exposure, the supernatants and cells were collected. The protein levels of p22(phox), p47(phox), phosphorylated p38MAPK, total p38MAPK were measured by Western blotting. The gene expressions of p22(phox), p47(phox) were detected by RT-PCR. The levels of intracellular reactive oxygen species (ROS) were determined by flow cytometry. The levels of superoxide dismutase (SOD) and maleic dialdehyde (MDA) in the supernatant were determined respectively.


RESULTS
Compared with the control group, the expression levels of p22(phox), p47(phox), phospho-p38 and ROS significantly increased, activity of SOD decreased in high glucose group, while the level of MDA greatly increased (P < 0.01). Pioglitazone significantly suppressed p22(phox), p47(phox) expressions and oxidative stress induced by high glucose. The expressions of p22(phox), p47(phox), phospho-p38MAPK and ROS generation were markedly reduced after pioglitazone treatment (P < 0.05). The activity of SOD in the the supernatant increased (P < 0.05), while the level of MDA decreased greatly by pioglitazone (P < 0.05). The level of oxidative stress was associated with the phosphorylation level of p38MAPK (P < 0.01).


CONCLUSIONS
Pioglitazone can inhibit oxidative stress through suppressing NADPH oxidase expression and p38MAPK phosphorylation.
Department of Endocrinology, Anhui Provincial Hospital, Anhui Medical University, Hefei, Anhui 230001, China.
Shan
S
Wang
Shan-Dong
SD
Ye
Wen-Jia
WJ
Sun
Yuan-Yuan
YY
Hu
D000818:Animals; D015153:Blotting, Western; D005947:Glucose / Q000494:pharmacology; D050527:Mesangial Cells / Q000187:drug effects / Q000201:enzymology*; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D000077205:Pioglitazone; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D045162:Thiazolidinediones / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism
D017382:Reactive Oxygen Species; D045162:Thiazolidinediones; D019255:NADPH Oxidases; C515768:Cyba protein, rat; C060505:neutrophil cytosolic factor 1; D048051:p38 Mitogen-Activated Protein Kinases; D005947:Glucose; D000077205:Pioglitazone