Figure 3.

Histological and immunohistochemical analysis of the HEC #1-implanted sites. Hematoxylin and eosin (HE) stain, toluidine blue (TB) stain, and immunohistochemical analysis by using antibodies against vimentin, type II collagen (COL II), and type II collagen (COL II) are shown from left to right. With TB stain, the extracellular matrix of cartilage exhibited metachromasia diffusely in the nodules by P0 and P1 cells and focally in the nodules by P2 cells. The matrix of the nodules by P0 and P1 cells was positive for COL II at the center and with type I collagen (COL I) at the periphery. The nodule by P2 cells was focally COL II-positive and diffusely COL I-positive matrix. The matrix in the nodules by P3 and P5 cells was not stained with COL II and showed weakly positive reaction with COL I. The nodules by P7 cells were negative for COL II and COL I. The microscopic views (the same as Figure 2(c)) with HE stain (HE) are also shown for reference.