Inhibitory effect of all￣trans retinoic acid on osteogenic differentiation of mouse embryonic palate mesenchymal cells and its possible mechanism / 中国药理学与毒理学杂志

ABSTRACT

OBJECTIVE To investigate the effect and related mechanism of all￣trans retinoic acid (atRA) exposure on osteogenic differentiation of mouse embryonic palate masenchymal cells MEPM. METHODS MEPM were cultured in osteogenic medium (OM) with atRA 0.1 and 1.0 μmol??L-1 for 1, 3,5, 7 and 9 d. MTT assay was performed to measure the cell viability. The alkaline phosphatase (ALP) activity was measured by chemical colorimetry. The cells were stained using the Von￣Kossa technique to detect the formation of mineralization nodules after 21 d of culture. RT￣PCR was performed to determine expression Runx2, osteopontin, bone morphogenetic protein receptor ( Bmpr) 1b, Bmpr2 and Smad5 mRNA. RESULTS The result of MTT on 9 d showed that, compared with normal control group, the cell viability of OM, OM+atRA 0.1 and 1.0 μmol??L-1 groups decreased significantly(P<0.01). Compared with normal control group, ALP activity of OM group increased significantly(P<0.05), while the ALP activity of OM+atRA 0.1 and 1.0 μmol??L-1 groups was lower than OM group(P<0.05). On 21 d, the Von￣Kossa stai￣ning results showed that the percentage of mineralization nodules formation of OM+atRA 1.0 μmol??L-1 group was (3.65±1.24)%, which was significantly lower than that of OM group(10.33±2.29)%(P<0. 05). On 9 d, the relative Run expression of OM group was the highest one in the four groups, while at￣RA 1.0 μmol??L-1 treatment negatively regulated 20% in comparsion with OM group(P<0.05). Compared with normal control group, the mRNA expression of osteopontin of OM, OM+atRA 0.1 and 1.0 μmol??L-1 groups increased significantly(P<0.05); BDNF mRNA expression of OM group was 2.6￣fold to normal control group, while that of OM+atRA 1.0 μmol??L-1 group was 33% to OM group(P<0.05) . The level of Smad5 mRNA of OM+atRA 1.0 μmol??L-1 group was significantly lower than that of OM group(P<0.05). CONCLUSION atRA Might inhibit osteogenic differentiation of MEPM by down￣regulated the expression of Bmpr1b.