In vitro biophysical strain model for understanding mechanisms of osteopathic manipulative treatment.
BACKGROUND
Normal physiologic movement, pathologic conditions, and osteopathic manipulative treatment (OMT) are believed to produce effects on the shape and proliferation of human fibroblasts. Studies of biophysically strained fibroblasts would be useful in producing a model of the cellular mechanisms underlying OMT.


OBJECTIVE
To investigate the effects of acyclic in vitro biophysical strain on normal human dermal fibroblasts and observe potential changes in cellular shape and proliferation, as well as potential changes in cellular production of nitric oxide, interleukin (IL) 1beta, and IL-6.


METHODS
Randomized controlled trial. Human fibroblasts were subjected in vitro to control conditions (no strain) or biophysical strain of various magnitudes (10%-30% beyond resting length) and durations (12-72 hours). After control or strain stimuli, fibroblasts were analyzed for potential changes in cell shape, proliferative capacity, nitric oxide secretion, and cytokine (IL-1beta, IL-6) secretion.


RESULTS
Low strain magnitudes (<20%) induced mild cellular rounding and pseudopodia truncation. High strain magnitudes (>20%) decreased overall cell viability and the mitogenic response, and induced cell membrane decomposition and pseudopodia loss. No basal or strain-induced secretion of IL-1beta was observed. Interleukin 6 concentrations increased two-fold, while nitric oxide levels increased three-fold, in cells strained at 10% magnitude for 72 hours (P<.05).


CONCLUSIONS
Human fibroblasts respond to in vitro strain by secreting inflammatory cytokines, undergoing hyperplasia, and altering cell shape and alignment. The in vitro biophysical strain model developed by the authors is useful for simulating a variety of injuries, determining in vivo mediators of somatic dysfunction, and investigating the underlying mechanisms of OMT.
Department of Physiology, Midwestern University/Arizona College of Osteopathic Medicine, 19555 N 59th Ave, Glendale, AZ 85308-6813, USA.
John G
JG
Dodd
Meadow Maze
MM
Good
Tammy L
TL
Nguyen
Andersen I
AI
Grigg
Lyn M
LM
Batia
Paul R
PR
Standley
D001696:Biomechanical Phenomena; D002478:Cells, Cultured; D016207:Cytokines / Q000032:analysis / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology*; D006801:Humans; D066298:In Vitro Techniques; D026301:Manipulation, Osteopathic; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013180:Sprains and Strains / Q000503:physiopathology; D013314:Stress, Mechanical
D016207:Cytokines