This paper is aimed to investigate the effect of rest-inserted loading on the mechanosensitivity of osteocytes. In the investigation, cultured MLO-Y4 osteocyte-like cells were strained on cyclic compressive force (CCF) by the self-made compressive loading device. Then we observed the effect of different rest periods-inserted loading (5 s, 15 s, 30 s, respectively) on the mechanosensitivity of osteocytes. We then determined the levels of secreted nitric oxide (NO) and prostaglandin E2 (PGE2) by Griess method and enzyme linked immunosorbent assay (ELISA), respectively. We then stained the cytoskeleton F-actin using immunofluorescence. We found that the expressions of NO and PGE2 in rest-inserted strained groups (>15 s) were significantly increased compared to those in the continuous strained group. And rest-inserted loading promoted the parallel alignment of stress fibers. It indicates that rest-inserted loading could promote the mechanosensitivity of osteocytes, and this might be related to the parallel alignment of stress fibers.
Mechanoresponsive microRNAs are a type of miRNAs which are sensitive or responsive to mechanical strain applied to them, their expression levels were changed after mechanical loading, thus affecting the expression levels of mRNA and proteins they regulated. Up to now, some mechanoresponsive miRNAs have been discovered in physiological or pathological tissues or organs. However, these discoveries are usually limited, and they are not able to guide clinical practice well. According to this situation, this paper summarizes research findings of mechanoresponsive miRNAs, and provides directions for clinical practice and further researches.
As a kind of mechanical effector cells, chondrocytes can produce a variety of physical and chemical signals under the stimulation of multiaxial load in vivo, which affect their own growth, development and apoptosis. Therefore, simulating the mechanical environment in vivo has become a research hotspot in the culture of chondrocytes in vitro. Although a large number of reports have fully proved that different mechanical stimulation can regulate the metabolism of chondrocytes, the loading scheme has not been agreed. Starting from different mechanical forms, this review will explore the differences in the regulation of chondrocyte metabolism by different mechanical stimuli, so as to find an advantage scheme to promote the growth and proliferation of chondrocytes and to develop a more stable, effective and reliable experimental strategy.
Objective To summary the regulatory effect of mechanical stimulation on macrophage polarization in wound healing, and explore the application prospect of mechanical stimulation in tissue engineering. Methods The related domestic and foreign literature in recent years was extensive reviewed, and the different phenotypes of macrophages and their roles in wound healing, the effect of mechanical stimulation on macrophage polarization and its application in tissue engineering were analyzed. Results Macrophages have functional diversity, with two phenotypes: pro-inflammatory (M1 type) and anti-inflammatory (M2 type), and the cells exhibit different activation phenotypes and play corresponding functions under different stimuli. The mechanical force of different types, sizes, and amplitudes can directly or indirectly guide macrophages to transform into different phenotypes, and then affect tissue repair. This feature can be used in tissue engineering to selectively regulate macrophage polarization. Conclusion Mechanical stimulation plays an vital role in regulating macrophage polarization, but its specific role and mechanism remain ambiguous and need to be further explored.