Effects Of MiR-335-5PON The Function Of Osteoblast In High Glucose Condition

Objective:This study is to investigate the effects of microRNA (miR)-335-5p on the proliferation and apoptosis in osteoblasts induced by high glucose (HG), and the related mechanisms.Methods:MC3T3-E1 osteoblasts were cultured for 7 d with different concentration of glucose and were divided into control group (concentration of glucose:5.5 mmol/L), HG group (concentration of glucose:22.0 mmol/L), agomir-335-5p group (transfected with agomir-335-5p and exposed to 22.0 mmol/L glucose) and agomir NC group (transfected with agomirnegative controland exposed to 22.0 mmol/L glucose). The proliferation of MC3T3-E1 osteoblasts was mesured by MTT method. Cellular apoptosis was detected with flow cytometry. The expression levels of mRNAs and miRNAs, and proteins were detected by real-time PCR and Western blot analysis, respectively.Results:(1) Compared with the control group, the expression level of miR-335-5p was significantly down-regulated in the HG group (P< 0.05), and it was higher in agomir-335-5p group than in HG group and agomirNC group (P< 0.05).However, no significant differences were observed in the mRNA expression levels of DKK1 between these groups. (2)The cell proliferation in the HG group was decreased compared with that in the control group, while it was elevated in agomir-335-5p group compared with in the HG group (P< 0.05). Cell apoptosis rate was increased in the HG group compared with the control group, while the over-expression of miR-335-5p significantly decreased the apoptosis rate in these model cells (P< 0.05). (3) The protein expression levels ofDKK1 and caspase-3 were both significantly elevated in the HG group than in control group, which were significantly down-regulated by the overexpression of miR-335-5p (P < 0.05).Conclusion:Over-expression of miR-335-5p could inhibit the high glucose-induced apoptosis of MC3T3-E1 osteoblasts and promote the cell proliferation through decreasing the protein expression levels ofDKKl. Our results suggest that miR-335-5p might be a potential target for the treatment of diabetic osteoporosis.