Figure 2.

Hematoxylin-eosin staining (original magnification ×20) showing limited cellularity (purple nuclei) and abundant extracellular matrix (orange matrix) in circumferential samples obtained from the central body of the meniscus (A). Alcian blue staining for proteoglycans is limited to the interstitial areas outside of dense collagen bundles (B). Dense collagenous matrix of the meniscus is visualized through picrosirius red staining (C). Polarized light microscopy analysis of picrosirius red-stained sections reveals a highly organized network of collagen fibers within the macroscopic circumferential bundles (D). Typical stress-strain response of meniscus samples tested in the circumferential and radial directions (E). The tensile modulus in the circumferential direction is approximately 6 times higher than in the radial direction (F).