Fig. 3

2D (a, b) µCT images of the tibial epiphysis from a sham rat (A) and MMT rat (B). Doted squares indicate area of subchondral bone used for zonal analysis. 3D images of subchondral bone are depicted for sham (Aa) and MMT rat (Bb). Arrow indicates thicker subchondral bone in MMT rat. C (sham) and D (MMT) shows a contrast µCT image of the proximal tibial epiphysis of the same rats shown in A and B. The length of the medial tibial plateau was measured for each sample and was then divided into three zones ranging from 0.8 to 1.0 mm in length. Zone 1 (z1) was placed on the outside of the medial edge of the joint, and Zone 3 (z3) was placed on the inside of the tibial plateau, adjacent to the central collateral ligaments as exemplified in C. Zones are delineated by dotted lines. Cc (sham) and Dd (MMT) show color thickness (“heat”) maps of the articular cartilage at the medial tibial plateau. Arrow indicates a lack of viable cartilage that covers the medial tibial plateau in MMT rat