Effects of miR-335-5p on the osteoblast function in high glucose condition

Objective To investigate the effects of miR-335-5p on the proliferation and apoptosis of osteoblasts which were exposed to high glucose condition, and explore its possible molecular mechanisms. Methods MC3T3-E1 osteoblasts were divided into four groups: control group(5.5 mmol/L glucose), high glucose group(HG group, 22.0 mmol/L glucose), agomir-335-5p group(transfected with agomir-335-5p and exposed to 22.0 mmol/L glucose), and agomir negative control group(agomir NC group, transfected with agomir negative control and exposed to 22.0 mmol/L glucose), cultured for 7 days. Cell proliferaton, cell apoptosis, expressions of miR-335-5p and dickkopf homolog 1(DKK1) mRNA, protein levels of DKK1 and cysteinyl aspartate-specific proteinase-3(caspase-3) were detected using MTT, flow cytometry, quantitative realtime PCR and western blot, respectively. Results Compared with control group, the expression of miR-335-5p mRNA and cell proliferation in HG group were significantly decreased(P 0.05). The miR-335-5p mRNA expression and cell proliferation in agomir-335-5p group were higher than those in HG group and agomir NC group(P<0.05). However, Cell apoptosis and the protein levels of DKK1 and caspase-3 in agomir-335-5p group were lower than those in HG group(P<0.05). Conclusion High glucose inhibits the proliferation and induce the apoptosis of MC3T3-E1 osteoblast through decreasing the expression of miR-335-5p and subsequently increasing the DKK1 expression. (Chin J Endocrinol Metab, 2015, 31: 712-716) Key words: miR-335-5p; Osteoblast; Proliferation; Apoptosis