Figure 1. Analysis of collagen distribution. Picrosirius red staining was used to evaluate collagen fibers of the annulus fibrosus (AF), under normal and polarized light, during intervertebral disc degenerative process. A, C and E normal light evaluation; B,D and F polarized light; 28 days, AF obtained 28 days after degenerative induction; 25 days, AF obtained 25days after degenerative induction. Fibers association (red); new fibrils formation (green).