Mechanical loading influences osteocytes and further regulates osteoblast metabolism and osteogenic differentiation(miRNA Array)

A previous study indicated that mechanical tensile strain of 2500 microstrain (με) at 0.5 Hz for 8 h promoted osteogenesis and corresponding mechanoresponsive microRNAs (miRs) were identified in osteoblasts. However, in osteocytes, it has not been identified which miRs respond to the mechanical strain, and it is not fully understood how the mechanoresponsive miRs regulate osteoblast differentiation. Mouse MLO-Y4 osteocytes were applied to the same mechanical tensile strain in vitro.MiR microarray and reverse transcription-quantitative polymerase chainreaction(RT-qPCR) assays were applied to select and validate differentially expressed miRs, and the target genes of these miRs were then predicted. In addition, the differentially expressed miRNAs in mechanically strained osteocytes in vitro were compared with those in treadmill exercise of the bone tissues . In this study, the osteocytes’biological response to a mechanical tensile strain of 2500με at 0.5 Hz for 8 h was investigated, and some novel mechanosensitive miRs were selected. In addition, the involvement of miR-29b in osteocytes’response to mechanical strain and osteoblast differentiation were studied. Total RNAs was extracted from MLO-Y4 osteocytes of mechanical loading .MiRNA microarray was used to acquire expression profiles of a total of 1900 unique miRNAs