| BackgroundMuscle injury is one of the most common injuries in sports;however,the ability of muscle tissue to repair itself is limited,and severe muscle injury can lead to volumetric muscle loss(VML),and extensive muscle injury and tissue loss can lead to permanent loss of function.Autologous transplantation of healthy muscle tissue is the current clinical standard for the treatment of severe muscle injury.However,surgical transplantation has significant limitations and faces problems including lack of donor tissue,loss of donor site function,and survival of the transplanted tissue.An in situ regeneration strategy based on skeletal muscle tissue engineering is a promising approach to repair skeletal muscle injury.ObjectiveConstruction of a micro-and nano-structured piezoelectric composite hydrogel as a functional tissue engineering scaffold to promote the repair of skeletal muscle tissue damage.Methods1.Chemically cross-linked sodium hyaluronate grafted with double bonds and sodium carboxymethylcellulose with aldehyde groups,compounded with piezoelectric nanoparticles of barium titanate modified with polypyrrole,to prepare the obtained hydrogels,and then endowed the hydrogels with grating-like microstructures,and characterized the physicochemical properties of the prepared micro-and nanostructured composite piezoelectric hydrogels.2.To evaluate the biocompatibility of the hydrogels;to investigate the role of different scale microstructures on myogenic cell morphology by staining the cytoskeleton with ghost pen cyclic peptide.3.To model the tibialis anterior muscle in rats and implant hydrogel scaffolds at the defect site,and evaluate the effect of different hydrogel scaffolds on repairing muscle damage by histological staining(H&E and Masson)and immunolabeling.Results1.HGA4C/2BTO group hydrogels had a uniformly distributed high porosity(82.93±2.31%)microstructure,a pore size of about 22.15±7.11 μm,and suitable mechanical properties.2.HGA4C/2BTO group hydrogels had good biocompatibility,and the grating-like microstructure of 50 μm size can better induce myogenic cells to be arranged in a directional manner.3.The 50 pm microstructured hydrogel scaffold was able to promote the repair of skeletal muscle injury,as well as induce the polarization of macrophages towards the pro-repair M2 type and the regeneration of microvessels.ConclusionIn the present study,we successfully constructed a micro-and nano-structured piezoelectric composite hydrogel.This hydrogel has similar physicochemical properties to the extracellular matrix of skeletal muscle and has good biocompatibility.The hydrogel with 50μm size microstructure can better induce directional alignment of myogenic cells;it can significantly promote the regeneration of rat skeletal muscle tissue in vivo,as well as promote macrophage polarization and microangiogenesis,providing evidence for in situ regeneration of damaged skeletal muscle. |
