Mechanical stimulation in vitro regulates pro-inflammatory cytokines: potential insight into soft tissue manual therapies for osteopenia and sarcopenia

Objecti ve: 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. Previous studies established an in vitro model system for examining mechanical stimulation of dermal fibroblasts and established that cyclical strain, intended to mimic overuse injury, induces 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. We have also begun to extend these reports through the use of differentiation assays using osteoblastic precursors from both calvaria and long bone cells. We observe this differentiation into osteoblasts from the precursors when they are exposed to conditioned media containing the pro-inflammatory cytokines from the aforementioned mechanical strain and therapy studies. Results: Using cultures of primary human dermal fibroblasts, primary human skeletal myocytes, and murine C2C12 satellite cells, we confirm, in fibroblasts, that cyclical mechanical strain increases levels of IL-6 and adding long-duration stretch, intended to mimic therapeutic soft tissue stimulation, after cyclical strain results in lower IL-6 levels. We also extend the prior work, reporting that long duration stretch results in lower levels of IL-8 in fibroblasts, as well as provide novel data showing cytokine changes in the myocytes and satellite cells. Although there are important limitations to this experimental model, these findings provide supportive evidence that therapeutic soft tissue stimulation may reduce levels of pro-inflammatory cytokines. In addition, we have exposed MC3T3E1 cells, an osteoblastic precursor from calvarial bone, and murine tibiae to the previously mentioned conditioned media containing these pro-inflammatory cytokines to observe its potential differentiation upon exposure. While this study did not provide any significant findings in the MC3T3E 1 line, it gave us key insight into our next steps for the differentiation assays. We also exposed another osteoblastic precursor, W-20-17, to the previously mentioned conditioned media. Gene expression analyses suggest that soft tissue manipulation (STM) increases osteoblast differentiation, as determined by expression of the osteoblast marker Osteocalcin. However, these preliminary results were not statistically significant and will need to be replicated before confirming this preliminary analyses. The tibiae showed an increased expression of the osteoblastic marker, P1NP and a decrease in CTx-1, a marker for bone resorption. One of these insights has led us to begin observing different cell lines, specifically cells originating from long bone. Future work is required to address these open questions and advance the mechanistic understanding of therapeutic soft tissue stimulation

Creator

• Larsen, Bryan
• Ogunbekun, Oladipupo
• Loghmani, M. Terry
• Thompson, William
• Hum, Julia
• Hiland, Taylor
• Lowery, Jonathan
• Mahoney, Aaron
• Anloague, Aric

Language

• English

Mot-clé

• Soft tissue manual therapies
• sarcopenia
• osteopenia
• pro-inflammatory cytokines

Date created

• 2020

Related URL

• Video Presentation:  https://marian.hosted.panopto.com/Panopto/Pages/Viewer.aspx?id=d8e8e92a-a53f-4531-8f44-ac7401880dfe

Resource type

• Poster

Rights statement

• http://rightsstatements.org/vocab/InC/1.0/