Influence of peroxisome proliferator activated receptor γ2 endogenous ligands on mRNA expression of bone metabolism related genes in osteoblastic cells / 中华内分泌代谢杂志

ABSTRACT

Objective To observe the effect of oxidized low-density lipoproteins (Ox-LDL),15-Deoxy-△ 12,14-prostaglandin J2 ( 15d-PGJ2 ),leukotrienes B4 ( LTB4 ) on mRNA expressions of peroxisome proliferator activated receptor γ2 ( PPARγ2 ),receptor activator of NF-κB ligand (RANKL),alkaline phosphatase ( ALP),and osteoprotegerin(OPG) in osteoblastic cells of rats; and to investigate the influence of these PPARγ2 endogenous ligands on bone metabolism.Methods Rat osteoblastic cells were cultured in vitro for 24 h in medium with different PPARγ2 endogenous ligands at various concentrations ( the final concentrations of Ox-LDL were 0,12.5,25,50μg/ml; the final concentrations of 15 d-PGJ2 were 0,10,20,30 μmol/L; the final concentrations of LTB4 were 0,0.1,1.0,10 μ mol/L).RT-PCR was performed to determine the mRNA expressions of PPARγ2,RANKL,ALP,and OPG in osteoblastic cells.Results RT-PCR analysis showed that Ox-LDL,15d-PGJ2,and LTB4 all down-regulated the mRNA expressions of RANKL,ALP,and OPG,while up-regulated the mRNA expressions of PPARγ2 in osteoblastic cells in a dose-dependent manner.Significant differences were found in interclass comparisons( P＜0.05 or P＜ 0.01 ).Conclusions These findings suggest that Ox-LDL,15d-PGJ2,and LTB4 suppress the expressions of osteogenic genes through activating the transcription activity of PPARγ2,and this may be a plausible mechanism of senile osteoporosis.