Figure 4: Biocompatibility Assessment and Muscle Fiber Morphology Quantification

(A) Hematoxylin and eosin (H&E) stained transverse section showing healthy fiber morphology. (B) Macrophages were stained with CD68 as shown (black arrow). (C) Extracellular matrix stained with a laminin antibody (green) and nuclei were counter stained (blue) for saline (n = 11), human umbilical cord matrix (hUC) (n = 10), and skeletal muscle matrix (SKM) (n = 9) treated animals. (D) Percent ECM was measured from laminin stained slides. (E) Percent of fibers with centrally located nuclei. (F) Average fiber area. (G) Average fiber circularity. (H) Average fiber roundness. Scale bars are 100 μm and all images are representative from an SKM hydrogel treated animal. *p < 0.05, **p < 0.01, ***p < 0.001, and αp < 0.001 compared to all other groups.