GelMA hydrogel scaffold containing curcumin-loaded solid lipid nanoparticles promotes the regeneration of degenerative discs

Abstract Intervertebral disc degenerative disease (IDD), which usually causes lower back and neck pain, is one of the most widespread musculoskeletal disorders and often causes a low quality of life. However, the surgical and conservative treatments commonly used in clinical practice are not effective. Previous studies have identified curcumin (Cur) as a potential therapeutic agent. However, its development in this regard has been limited due to its low dissolution, instability in water, and rapid metabolism. In this study, we developed a novel anti-inflammatory composite hydrogel scaffold with curcumin encapsulated in solid lipid nanoparticles and mixed it with gelatin methacrylate (GelMA) hydrogel to treat IDD. The hydrogel scaffold, denoted Cur-solid lipid nanoparticles (SLNs)/GelMA, promoted the restoration of Collagen type II (Col II) and aggrecan expression levels in vivo, indicating that the regeneration of the intervertebral discs was effective. Combined in vitro studies showed that Cur-SLNs inhibited the expression of the inflammatory factors TNF-α and IL-6. Additionally, immunofluorescence and western blotting experiments verified that Cur-SLNs regulated the recovery of Col II and aggrecan in an inflammatory environment and promoted the metabolic homeostasis of the extramedullary cell matrix. In conclusion, this study provides a new strategy to promote IDD regeneration, which brings new application prospects.