Repeated folding stress-induced morphological changes in the dermal equivalent.

Area of Science:

• Dermatology
• Biomechanical Engineering
• Molecular Biology

Background:

• Skin aging and wrinkle formation are linked to repeated mechanical stresses.
• The precise molecular mechanisms driving these morphological changes remain unclear.

Purpose of the Study:

• To investigate the effects of repeated mechanical stress on a dermal equivalent.
• To elucidate the cellular and molecular pathways involved in stress-induced skin changes.

Main Methods:

• Developed a novel device for applying repeated folding stress to a dermal equivalent.
• Analyzed morphological changes, collagen fibril orientation, and gene expression.
• Assessed the role of the RhoA-ROCK signaling pathway using a specific inhibitor.

Main Results:

• Repeated folding stress significantly decreased dermal equivalent width.
• Mechanical stress altered collagen fibril orientation but did not affect collagen content or cell viability.
• Inhibition of Rho-associated coiled-coil-containing kinase (ROCK) completely prevented width reduction.

Conclusions:

• The decrease in dermal equivalent width is due to unidirectional contraction, not collagen degradation or cell loss.
• The RhoA-ROCK signaling pathway mediates the mechanical stress-induced contraction in the dermal equivalent.
• Findings provide insight into the biomechanical basis of wrinkle formation.