Biomechanical and biochemical changes in murine skin during development and aging

Area of Science:

• Biophysics
• Biomaterials Science
• Dermatology

Background:

• Skin aging involves biochemical and biomechanical changes with functional consequences.
• Limited research quantifies microstructural changes and their link to macroscopic biomechanical behavior over time.
• Understanding tissue maturation requires connecting microscopic alterations to macroscopic properties.

Purpose of the Study:

• To investigate skin maturation and its biomechanical evolution across different age groups.
• To correlate microscopic skin changes with macroscopic biomechanical behavior in a murine model.
• To bridge the knowledge gap between microstructural alterations and macroscale tissue function over time.

Main Methods:

• Multiscale characterization of murine skin from newborn, adult, and aged mice.
• Mechanical testing: uniaxial loading, tension relaxation, loading to failure, inflation experiments.
• Microscopic analysis: histology, biochemistry, atomic force microscopy (AFM) indentation.

Main Results:

• Newborn skin exhibits significantly different biomechanical properties, reduced collagen, and altered cross-linking compared to adult skin.
• Adult and aged skin show similar biomechanical behavior within the physiological loading range.
• Aged skin demonstrates reduced tensile strength and stiffening at high force values, correlating with collagen alterations.
• Computational modeling revealed age-induced biomechanical changes influence the dermal cell biophysical environment.

Conclusions:

• Skin's microstructural and biomechanical properties undergo significant changes during maturation and aging.
• Aged skin maintains function in physiological ranges but weakens under high stress, linked to collagen changes.
• Age-related microstructural differences profoundly impact both tissue-level properties and the cellular biophysical environment.