Objective
In this study we modeled repetitive motion strain (RMS) and myofascial release (MFR) in vitro to investigate possible cellular and molecular mechanisms to potentially explain the immediate clinical outcomes associated with RMS and MFR.
Method
Cultured human fibroblasts were strained with 8 hours RMS, 60 seconds MFR and combined treatment; RMS+MFR. Fibroblasts were immediately sampled upon cessation of strain and evaluated for cell morphology, cytokine secretions, proliferation, apoptosis, and potential changes to intracellular signaling molecules.
Results
RMS induced fibroblast elongation of lameopodia, cellular decentralization, reduction of cell to cell contact and significant decreases in cell area to perimeter ratios compared to all other experimental groups (p<0.0001). Cellular proliferation indicated no change among any treatment group; however RMS resulted in a significant increase in apoptosis rate (p<0.05) along with increases in death-associated protein kinase (DAPK) and focal adhesion kinase (FAK) phosphorylation by 74% and 58% respectively, when compared to control. These responses were not observed in the MFR and RMS+MFR group. Of the twenty cytokines measured there was a significant increase in GRO secretion in the RMS+MFR group when compared to control and MFR alone.
Conclusion
Our modeled injury (RMS) appropriately displayed enhanced apoptosis activity and loss of intercellular integrity that is consistent with pro-apoptotic DAPK2 and FAK signaling. Treatment with MFR following RMS resulted in normalization in apoptotic rate and cell morphology both consistent with changes observed in DAPK2. These in vitro studies build upon the cellular evidence base needed to fully explain clinical efficacy of manual manipulative therapies.