Objective: To explore the reaction of normal skin fibroblasts from different sites of human body to cyclic stretch.
Methods: The normal skin tissues from scapular upper back and medial side of upper arm of 3 patients were cultured in vitro. Fibroblasts of experimental group were loaded by cyclic stretch with 10% amplitude for 24, 36, and 48 hours respectively. Fibroblasts of control group were cultured without cyclic stretch. The morphologic changes were observed using inverted microscope. CCK-8 method was used to detect the proliferation of the fibroblasts. The expressions of integrin beta1 mRNA, p130Crk-associated substance (P130Cas) mRNA, transform growth factor beta1 (TGF-beta1) mRNA, and collagen type I alpha1 chain (COL1A1) mRNA were detected by real-time quantitative PCR. The protein levels of collagen type I and TGF-beta1 were detected by ELISA.
Results: The cultured cells showed a significantly increased cell proliferation ability, and apparent orientation after the applied strain. The proliferation activity, mRNA expression levels of integrin beta1, P130Cas, and TGF-beta1, protein levels of TGF-beta1 in back skin were significantly higher than those in arm skin (P<0.05) when the fibroblasts were loaded for 36 and 48 hours, but no significant difference between back skin and arm skin at 24 hours (P>0.05). There was no significant difference in mRNA expression level of COL1A1 and protein level of collagen type I between back skin and arm skin at 24, 36, and 48 hours (P>0.05). There was no significant difference in all above indexes between back skin and arm skin in control group (P>0.05).
Conclusion: Fibroblasts from scapular upper back and medial side of upper arm display different reactions to cyclic stretch, which indicates that there exists site difference in the reactions of fibroblasts to cyclic stretch. It might be related with the incidence of hypertrophic scar in different sites of the body.