FIG. 5.

Gross morphology and histological comparison of tissue retrieved from implant region of injured TA muscle 12 weeks after keratin-based hydrogel treatment. As shown by the representative macroscopic tissue images of the leg, there were quite obvious differences in the gross appearance of the injured TA region among treatment groups. For example, the injury site was quite apparent in the NR animals and to a much lesser extent in the KN-treated groups. In fact, the KN-alone (no growth factor) TA muscle is virtually indistinguishable from an uninjured TA muscle. Although BAM implantation did not promote robust functional recovery, significant volume reconstitution was apparent. Also shown are hematoxylin–eosin staining (A, B, E, F, I, J, M, N, Q, R, U, V), wherein nuclei are stained in blue-purple and cytoplasm and cellular proteins are stained in red-pink, as well as Mason's Trichrome (C, D, G, H, K, L, O, P S, T, W, X), in which tissue stains red, collagen stains blue, and nuclei stain black. In all cases, staining was performed on longitudinal sections of TA muscle obtained from the injured regions of the respective treatment groups. Schematic representation on the upper left corner shows the region of the tibialis anterior where histological analysis was performed. (A-–D) NR, (E–-H) BAM, (I-–L) KN, (M–-P) KN+I, (Q–-T) KN+b, and (U–-X) KN+I+b. Yellow arrows denote regions with new muscle fiber formation. *Denotes regions with native muscle. Yellow inset on (P) highlights new vessel formation. Color images available online at www.liebertpub.com/tea