Composition, structure and tensile biomechanical properties of equine articular cartilage during growth and maturation

Abstract

Articular cartilage undergoes structural and biochemical changes during maturation, but the knowledge on how these changes relate to articular cartilage function at different stages of maturation is lacking. Equine articular cartilage samples of four different maturation levels (newborn, 5-month-old, 11-month-old and adult) were collected (N = 25). Biomechanical tensile testing, Fourier transform infrared microspectroscopy (FTIR-MS) and polarized light microscopy were used to study the tensile, biochemical and structural properties of articular cartilage, respectively. The tensile modulus was highest and the breaking energy lowest in the newborn group. The collagen and the proteoglycan contents increased with age. The collagen orientation developed with age into an arcade-like orientation. The collagen content, proteoglycan content, and collagen orientation were important predictors of the tensile modulus (p < 0.05 in multivariable regression) and correlated significantly also with the breaking energy (p < 0.05 in multivariable regression). Partial least squares regression analysis of FTIR-MS data provided accurate predictions for the tensile modulus (r = 0.79) and the breaking energy (r = 0.65). To conclude, the composition and structure of equine articular cartilage undergoes changes with depth that alter functional properties during maturation, with the typical properties of mature tissue reached at the age of 5–11 months.

Dataset on equine cartilage near infrared spectra, composition, and functional properties

“…The presented profiles (Fig. 3d) of collagen content, proteoglycan content, and collagen orientation angle closely resemble those previously reported in literature 31,48–51 .…”

Surgical osteochondral defect repair in the horse—a matter of form or function?

“…The zonal arrangement of collagen type 2 within the extracellular matrix in a very specific arcade configuration is a crucial biomechanical feature for resilience of mature native articular cartilage (Figure ). Collagen structure and fibril orientation can be assessed through a number of novel technologies in a noninvasive manner . Fourier transform infrared microspectroscopy, polarised light microscopy and near infra‐red spectroscopy have been used in the equine joint to assess developmental changes during growth and to evaluate perilesional areas and the proprieties of the repair cartilage .…”

Simultaneous tractography and elastography imaging of the zone-specific structural and mechanical responses in articular cartilage under compressive loading

“…However, such "bending" behavior would have induced significant deformation in the lateral direction, which was not observed in the strain results. Therefore, we speculate that the realignment of the upper radial fibers observed in this sample may be attributed to nonclassical mechanical mechanisms for example, reorganization of collagen crosslinking [50]. More studies are necessary to clarify this observation.…”