Abstract
BackgroundTransplanting myogenic cells and scaffolds for tissue engineering in skeletal muscle have shown inconsistent results. One of the limiting factors is neovascularization at the recipient site. Low intensity shockwave therapy (Li-SWT) has been linked to increased tissue regeneration and vascularization, both integral to survival and integration of transplanted cells. This study was conducted to demonstrate the response of myoblasts and skeletal muscle to Li-SWT.MethodPrimary isolated human myoblasts and explants were treated with low intensity shockwaves and subsequently cell viability, proliferation and differentiation were tested. Cardiotoxin induced injury was created in tibialis anterior muscles of 28 mice, and two days later, the lesions were treated with 500 impulses of Li-SWT on one of the legs. The treatment was repeated every third day of the period and ended on day 14 after cardiotoxin injection.. The animals were followed up and documented up to 21 days after cardiotoxin injury.ResultsLi-SWT had no significant effect on cell death, proliferation, differentiation and migration, the explants however showed decreased adhesion. In the animal experiments, qPCR studies revealed a significantly increased expression of apoptotic, angiogenic and myogenic genes; expression of Bax, Bcl2, Casp3, eNOS, Pax7, Myf5 and Met was increased in the early phase of regeneration in the Li-SWT treated hind limbs. Furthermore, a late accumulative angiogenic effect was demonstrated in the Li-SWT treated limbs by a significantly increased expression of Angpt1, eNOS, iNOS, Vegfa, and Pecam1.ConclusionTreatment was associated with an early upregulation in expression of selected apoptotic, pro-inflammatory, angiogenic and satellite cell activating genes after muscle injury. It also showed a late incremental effect on expression of pro-angiogenic genes. However, we found no changes in the number of PAX7 positive cells or blood vessel density in Li-SWT treated and control muscle. Furthermore, Li-SWT in the selected doses did not decrease survival, proliferation or differentiation of myoblasts in vitro.
Highlights
Transplanting myogenic cells and scaffolds for tissue engineering in skeletal muscle have shown inconsistent results
Proliferation and apoptosis of myoblasts were not affected by Low intensity shockwave therapy (Li-SWT) Cells were treated with 300, 500, 1000 and 1500 impulses of Li-SWT and cell death subsequently quantified by tryphan blue uptake
5.6% in the Li-SWT treated compared to 1.7–3.0% in controls, and we found no significant difference in cell death (Fig. 1a)
Summary
Transplanting myogenic cells and scaffolds for tissue engineering in skeletal muscle have shown inconsistent results. A promising, non-invasive, indirect technique to improve vascularisation is a low intensity shockwave treatment (Li-SWT) This is increasingly employed in regenerative medicine and wound healing [9,10,11] clinical studies conducted so far have not Hansen et al BMC Musculoskeletal Disorders (2017) 18:557 advocated the use of SWT in the clinic. Shockwaves affect tissue by a direct mechanical force and by creating bubble cavitations that burst, generating a jet flow affecting nearby cells [12,13,14] This results in minor intra- and extracellular damages, shear stress and conversion of mechanical force into chemical activity (known as mechanotransduction) [14, 15] inducing a regenerative response in the involved tissue
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
