Decellularized human amniotic particles reinforced with GelMA assist wound healing of the oral mucosa in vivo

Defects within the oral mucosa can result from a variety of causes, including tumors and trauma. Adults have limited ability to regenerate after tissue loss or injury, meaning autografts to reconstruct defects are often required. Due to shortcomings associated to tissue transplantation, the use of tissue engineering technology to reconstruct and regenerate oral tissues has gained attention. In this regard, HAM (human amniotic membrane) was utilized as a biological material for tissue engineering applications. However, its unfavorable properties have limited its use, and hybrid scaffolds based on HAM have been investigated. Thus, in this study, a biomimetic hybrid scaffold composed of gelatin methacryloyl and decellularized human amniotic particles (GelMA-dHAP) was prepared and used as a tissue substitute to promote wound healing of the oral mucosa in rabbits. First, the degradation and swelling characteristics of the scaffold were evaluated and found to be more desirable than those of GelMA alone. Then, the effects of the GelMA-dHAP stent on the proliferation and differentiation of human foreskin fibroblasts were studied in vitro using a cell counting kit-8 (CCK8) and immunofluorescence, respectively. This showed that the hybrid scaffold could significantly promote fibroblast proliferation and differentiation in comparison to controls. Following these initial assessments and to better understand the underlying mechanism of wound healing, in vivo histological and immunohistochemical studies were undertaken using a rabbit oral mucosa defect model. The results showed that GelMA-dHAP can promote angiogenesis and collagen expression within the oral mucosa. Importantly, the GelMA-dHAP scaffold was shown to assist wound healing better than GelMA alone, demonstrating the potential of the hybrid scaffold in tissue engineering.