Bioactive and degradable collagen-based hydrogel encapsulated with microspheres containing basic fibroblast growth factor (bFGF) and interleukin (IL)-10 promotes recovery following traumatic spinal cord injury in rats

Traumatic spinal cord injury (TSCI) is a severe event within the central nervous system, leading to the impairment of sensory and motor abilities at the injury site in the spinal cord. Current therapeutic approaches offer limited efficacy in improving recovery, underscoring the need to explore alternative treatments. In the present study, we examined the sustained co-delivery of basic fibroblast growth factor (bFGF) and interleukin-10 (IL-10), encapsulated in microspheres and incorporated into a collagen-based hydrogel, for its effects on the healing of TSCI in an animal model. Seventy-five male Sprague Dawley rats were randomly divided into five groups: control, TSCI, hydrogel, microspheres, and hydrogel loaded with microspheres (Hyd + Micro). Tissue samples were collected from the injury site for further evaluation. Compared to the TSCI group, treatment groups demonstrated notably higher numerical densities of neurons and greater motor neuron health, as well as increased levels of vascular endothelial growth factor (VEGF) and antioxidative factors (catalase [CAT], glutathione [GSH], and superoxide dismutase [SOD]), and improved neurological function scores (electromyography [EMG], Basso–Beattie–Bresnahan (BBB) test, and narrow beam-walking test [NBT]). These changes were most pronounced in the Hyd + Micro group. The treatment also led to a significant decrease in the counts of apoptotic and glial cells, alongside reduced levels of malondialdehyde (MDA) and pro-inflammatory cytokines (IL-1β and TNF-α), with the most notable enhancements seen in the Hyd + Micro group. These findings indicate that the co-delivery of bFGF and IL-10 encapsulated in microspheres within a collagen-based hydrogel provides enhanced neuroprotective effects in TSCI animal models.