Cell-scaffold transplant of hydrogel seeded with rat bone marrow progenitors for bone regeneration.

Bone is the second most frequently transplanted tissue in humans and efforts are focused on developing cell-scaffold constructs which can be employed for autologous implantation in place of allogenic transplants. The objective of the present study was to examine the efficacy of a gelatin-based hydrogel scaffold to support osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (MSCs) and its application in a cranial defect model. MSCs which were cultured on hydrogel under osteogenic conditions demonstrated typical osteogenic differentiation which included cluster formation with positive Alizarin Red S staining, sedimentation of calcium phosphate as defined by SEM and EDS spectroscopy and expression of mRNA osteogenic markers. Empty scaffolds or those containing either differentiated cells or naïve cells were implanted into cranial defects of athymic nude mice and the healing process was followed by μCT. Substantial bone formation (65%) was observed with osteogenic cell-scaffold constructs when compared to the naïve cell construct (25%) and the cell free scaffold (10%). Results demonstrated the potential of hydrogel scaffolds to serve as a supportive carrier for bone marrow-derived MSCs.