Hydrogels have been used as promising
biomaterials for regeneration and control of pathophysiological events after traumatic
spinal cord injuries (TSCI). However, no systematic comparison was conducted to show the effect of
hydrogels on pathophysiological events. This study was designed to address this issue and evaluate the regenerative potential of
hydrogels after TSCI. From 2857 records found in MEDLINE and EMBASE databases (April 23, 2021), 49 articles were included based on our inclusion/exclusion criteria. All studies discussing the effect of
hydrogels on at least one of the main pathophysiological events after TSCI, including
inflammation, axon growth, remyelination,
glial scar formation, cavity size, and locomotor functional recovery were included. For statistical analysis, we used mean difference with 95% confidence intervals for locomotor functional recovery. The results showed that both natural and synthetic
hydrogels could reduce the inflammatory response, hinder
glial scar formation, and promote axon growth and vascularization. Also, the meta-analysis of the BBB score showed that using the
hydrogels can lead to locomotor functional recovery. It was found that
hydrogels are more efficient when used in transection and hemisection
injuries (SMD: 1.89; 95% CI: 1.26, 2.52; P < .00001) compared to other injury models. The pre-formed implanted
hydrogels (SMD: 1.79; 95% CI: 1.24, 2.34; P < .00001) found to be more effective compared to injection (SMD: 1.58; 95% CI: 0.64, 2.52; P = 0.0009). In conclusion, based on the available evidence, it was concluded that
hydrogel composition as well as implantation method are dominant factors affecting tissue regeneration after TSCI and should be chosen according to the injury model in animal studies.