Figure 11.

Targeted depletion of collagen V in tendon and ligament induces joint instability. A: Joint laxity and chronic fibrous inflammation presented in Col5a1^Δten/Δten mice knee joints at postnatal day 4. Sagittal sections of knee joints from postnatal day 4 mice show that the fibroblasts and fibers of the anterior cruciate ligament (ACL) align parallel in the ACL midsubstance in the control (Ctrl) mice. In the Col5a1^Δten/Δten ACL, the fibers were disorganized and wavy. The asterisks show synovial inflammation that contained fibrous connective tissue, blood vessels, and chronic inflammatory cells in the Col5a1^Δten/Δten ACL. Stain: H&E. B: Polarized light microscopy in control mice shows large, well-organized ACL fibers. In contrast, the fibers in Col5a1^Δten/Δten ACL are wavy and smaller. The specimens were the same as in A. Stain: picrosirius red.