Figure 4. The histological assessment (toluidine blue) of the ACLT and CI group.

Articular cartilage displayed a more severe matrix loss in CI rats at the 6th week than that in ACLT rats (I, L). Matrix fissure of cartilage was observed as early as 2 weeks in CI group after injection (H, K). For the Sham or Saline groups, the toluidine blue staining was almost homogeneous at the whole period (A, D, G, J).