Animal Models for Treating Spinal Cord Injury Using Biomaterials-Based Tissue Engineering Strategies

The aim of the study is to provide an up-to-date review of studies that used preclinical animal models for the evaluation of tissue engineering treatments for spinal cord injury (SCI), which involved the use of biomaterials with or without the addition of cells or biomolecules. Electronic search of the PubMed, Web of Science, and Embase databases was performed for relevant studies published between January 2009 and December 2019. In total, 1579 articles were retrieved, of which 58 studies were included for analysis. Among the included studies, rats were the most common species used for animal models of SCI, while complete transection was the most commonly used injury pattern. Immediate intervention after injury was conducted in the majority of studies, and 8 weeks was the most common final time point of outcome assessment. A wide range of natural and synthetic biomaterials with different morphologies were used as a part of tissue engineering treatments for SCI, including scaffolds, hydrogels, and particles. Experimental parameters in studies using SCI animal models to evaluate tissue engineering treatments should be carefully considered to match the purpose of the study. Biomaterials that have functional modifications or are applied in combination with cells and biomolecules can be effective in creating a permissive environment for SCI repair in preclinical animal models. Impact statement This review provides an up-to-date summary of the preclinical landscape where tissue engineering treatments involving biomaterials were tested in animal models of spinal cord injury (SCI). Using studies published within the last 10 years, novel perspectives were presented on the animal species used, injury pattern, timing of intervention and outcome measurement, and biomaterials selection, as well as a summary of the individual findings of each study. This review provides unique insight into biomaterials-based tissue engineering strategies that have progressed to testing in animal models of SCI, which will help shape future research in the field and propel the clinical translation of discoveries.