FIG. 9.

Representative safranin-O/fast green stained samples from different experimental groups at 12 weeks after operation in rat caudal spines. In the normal disc (A, E, I), the boat-shaped NP comprised a large area in the disc space and was stained strongly for safranin-O (A, E). The annulus fibrosus displayed a normal pattern of fibrocartilage lamellas (I). In the NF scaffold group (B, F, J), the engineered NP contained abundant new extracellular matrix (B, F), and the annulus was similar to the normal group although with a slightly wavy structure (J). In the SW group (C, G, K), the engineered NP was hypocellular and consisted of larger areas of fibrous tissue (C, G), the annulus showed a serpentine appearance (K). In the sham control group (D, H, L), the nucleus pulpous structure nearly completely disappeared and the disc space was collapsed (D), with evident inhomogeneous tissue invasion (H). The annulus fibrosus in this group showed a severe serpentine appearance (L). The scale bars represent 200 μm in (A–D), 100 μm in (E–L). Color images available online at www.liebertpub.com/tea