Biomechanical and Compositional Changes in the Murine Uterus with Age

The uterus is a hollow, fibromuscular organ involved in physiologic processes such as menstruation and pregnancy. The content and organization of extracellular matrix constituents such as fibrillar collagen dictates passive (non-contractile) biomechanical tissue function; however, how extracellular matrix composition and biomechanical function change with age in the uterus remains unknown. This study utilizes Raman spectroscopy coupled with biaxial inflation testing to investigate changes in the murine uterus with age (2-3 months, 4-6 months, 10-12 months, and 20-24 months). Linear and toe moduli significantly decreased with reproductive aging (2 to 12 months); however, moduli increased in the oldest age group (20-24 months). The optical signature of combined elastin and collagen content was significantly higher in the oldest group (20-24 month), while the glycogen contribution was the highest in the 2-3 month murine uterus. The presented workflow couples biaxial inflation testing and Raman spectroscopy, representing a critical first step to correlating biomechanics and optical signatures in the aging uterus with the potential for clinical translation. Further, this study may provide critical compositional and structure-function information regarding age-related uterine disorders.