Figure 5

Comparison of subchondral bone structure using micro computed tomography (μCT). μCT analyses were performed to compare the subchondral bone structure between healthy (n = 5) and predisposed samples (n = 5). Five parameters were measured: the bone mineral density (BMD), the ratio between bone volume and total volume (BV/TV), the trabecular thickness (Tb,th), the trabecular number (Tb.nb) and the trabecular spacing (Tb,sp). Between-class correspondence analysis highlighted BMD, Tb,nb and Tb.sp as discriminating parameters between OC-affected and OC-free samples. Hierarchical clustering (A) based on these parameters showed that OCD-predisposed samples (horses OC1, OC2 and OC4) were clustered with healthy samples, whereas OC-predisposed samples (OC3 and OC5) were clustered separately. These observations suggested that OC-predisposed samples presented modified bone structure. The measures of the ratios between means of healthy and each predisposed group (B) seemed to confirm this assumption. The data suggested that the BMD and the Tb,nb were reduced in subchondral bone predisposed samples from osteochondral defect-affected foals, whereas Tb.sp was increased. Interestingly, the μCt analysis did not reveal any variation in bone-predisposed samples from OCD-affected foals.