Multiprotein collagen/keratin hydrogel promoted myogenesis and angiogenesis of injured skeletal muscles in a mouse model

Volumetric loss is one of the challenging issues in muscle tissue structure that causes functio laesa. Tissue engineering of muscle tissue using suitable hydrogels is an alternative to restoring the physiological properties of the injured area. Here, myogenic properties of type I collagen (0.5%) and keratin (0.5%) were investigated in a mouse model of biceps femoris injury. Using FTIR, gelation time, and rheological analysis, the physicochemical properties of the collagen (Col)/Keratin scaffold were analyzed. Mouse C2C12 myoblast-laden Col/Keratin hydrogels were injected into the injury site and histological examination plus western blotting were performed to measure myogenic potential after 15 days. FTIR indicated an appropriate interaction between keratin and collagen. The blend of Col/Keratin delayed gelation time when compared to the collagen alone group. Rheological analysis revealed decreased stiffening in blended Col/Keratin hydrogel which is favorable for the extrudability of the hydrogel. Transplantation of C2C12 myoblast-laden Col/Keratin hydrogel to injured muscle tissues led to the formation of newly generated myofibers compared to cell-free hydrogel and collagen groups (p < 0.05). In the C2C12 myoblast-laden Col/Keratin group, a low number of CD31+ cells with minimum inflammatory cells was evident. Western blotting indicated the promotion of MyoD in mice that received cell-laden Col/Keratin hydrogel compared to the other groups (p < 0.05). Despite the increase of the myosin cell-laden Col/Keratin hydrogel group, no significant differences were obtained related to other groups (p > 0.05). The blend of Col/Keratin loaded with myoblasts provides a suitable myogenic platform for the alleviation of injured muscle tissue.