Study Of Biological Response And Differential Expressed MicroRNAs Of Mechanical Tensile Strain Loaded Osteocytes

Objective: A cyclic mechanical tensile strain of 2500 ??,0.5 Hz for 8 h promoted osteogenesis in previous studies,this study aims to explore whether osteocytes could response to this kind of loading and whether there were mechanoresponsive molecules.Methods: Osteocytes-MLO-Y4 at confluence were loaded with a cyclic mechanical tensile strain of 2500 ??,0.5 Hz for 8 h via a four-point bending device.Expression levels of IGF-1/PGE-2 were assayed by ELISA,SOST was detected by Western blot,activities of NOS were detected by a biochemical method.Differential expression micro RNAs were detected by microarray and validated by q RT-PCR.Results: Expression levels of IGF-1?PGE-2?SOST and activities of NOS were higher compared to control,while activity of induced NOS increased most obvious.Following microarray selection,q RT-PCR validated 13 mi RNAs were up-regulated,3 mi RNAs were down-regulated among 40 micro RNAs with significant differences,in accordance with microarray results.Conclusions: Expression levels of IGF-1,PGE-2 and SOST and activities of NOS were increased after mechanical tensile strain of 2500 ??,0.5 Hz for 8 h,suggested MLO-Y4 cells were sensitive to this kind of loading,these four were all mechanoresponsive factors.Osteocytes regulate the activities of osteoblasts or osteoclasts via paracrine,thus regulating bone remodeling,these factors might play important roles in the process of osteocytes function as regulator.These 16 micro RNAs were all mechanoresponsive micro RNAs,likely to play a significant role in bone remodeling and reconstruction.