Objective Soft tissue manual therapies are commonly utilized by osteopathic physicians, chiropractors, physical therapists and massage therapists. These techniques are predicated on subjecting tissues to biophysical mechanical stimulation but the cellular and molecular mechanism(s) mediating these effects are poorly understood. A series of previous studies established an in vitro model system for examining mechanical stimulation of dermal fibroblasts and established that repetitive strain, intended to mimic overuse injury, induces the secretion of numerous pro-inflammatory cytokines. Moreover, mechanical strain intended to mimic soft tissue manual therapy reduces strain-induced secretion of pro-inflammatory cytokines. Here, we sought to partially confirm and extend these reports and provide independent corroboration of prior results.
Results Using cultures of primary human dermal fibroblasts, we confirm mechanical forces intended to mimic repetitive motion strain increases levels of IL-6 and that mechanical strain intended to mimic therapeutic soft tissue stimulation reduces IL-6 levels. We also extend the prior work, reporting that therapy-like mechanical stimulation reduces levels of IL-8. Although there are important limitations to this experimental model, these findings provide supportive evidence that therapeutic soft tissue massage may reduce inflammation. Future work is required to address these open questions and advance the mechanistic understanding of therapeutic soft tissue stimulation.