Development of a new formulation based on in situ photopolymerized polymer for the treatment of spinal cord injury

Spinal Cord Injury (SCI) promotes a cascade of inflammatory events that are responsible for neuronal death and glial scar formation at the site of the injury, hindering tissue neuroregeneration. Among the main approaches for the treatment of SCI, the use of biomaterials, especially gelatin methacryloyl (GelMA), has been proposed because it is biocompatible, has excellent mechanical properties, favoring cell adhesion and proliferation. In addition, it can act as a carrier of anti-inflammatory drugs, preventing the formation of glial scars. The present work presents the development and in situ application of a light-curing formulation based on GelMA containing a natural extract rich in anti-inflammatory, antioxidant and neuroprotective substances (hydroalcoholic extract of red propolisHERP) in an experimental model of SCI in rats. The formulations were prepared and characterized by time of UV exposition, FTIR, swelling and degradation. The hydrogels containing 1 mg/mL of HERP were obtained by the exposure to UV radiation of 2 L of the formulation for 60 s. The locomotor evaluation of the animals was performed by the scale (BBB) and demonstrated that after 3 and 7 days of the injury, the GelMA-HERP group (BBB = 5 and 7) presented greater recovery compared to the GelMA group (BBB = 4 and 5). Regarding the inflammatory process, using histomorphological techniques, there was an inflammation reduction in the groups treated with GelMA and GelMA-HERP, with decreases of cavitation in the injury site. Therefore, it is possible to conclude that the use of GelMA and GelMA-HERP hydrogel formulations is a promising strategy for the treatment of SCI when applied in situ, as soon as possible after the injury, improving the clinical and inflammatory conditions of the treated animals. View Full-Text This work was supported by the Banco do Nordeste (grant FUNDECI/2016.0015), National Council for Scientific and Technological (CNPq), Research and Technological Innovation Support Foundation of the State of Sergipe (Fapitec) and Coordination for the Improvement of Higher Education Personnel (CAPES). RLCAJ (309458/2019-6) and PS (301964/2019-0) thank CNPq for the financial support of the PQ scholarship. JCC thanks CNPq for the financial support of the DT scholarship (312451/2021/2). EBS acknowledges the Portuguese Science and Technology Foundation (FCT) for the project UIDB/04469/2020 (strategic fund) funded by national funds, and co-financed Education (FCT/MEC) from national fund