<p>The rat intervertebral discs including endplates, NP, and AF tissues were punctured with a needle and implanted into the dorsal skin pocket of athymic mice. The specimens were harvested at 1, 2, 4, and 6 months postoperatively. Tissue sections stained with Safranin-O for disc structure and constituent proteoglycan staining shown in red (A, 4 x magnification; B,10 x magnification). Arrow: hypertrophy chondrocytes. Five sections from four discs were used at each time point.</p
