Evaluation of different scaffolds for bone regeneration in rat calvarial bone defects

Abstract

Scaffold plays a key role in the context of tissue engineering. It not only provides a structural support for cells, but also creates an appropriate milieu for recruited cells, enhancing the therapeutic effects of cell-based treatments, and enabling the controlled release of biological cues such as growth factors. Collagen is widely used scaffold material in tissue engineering, particularly in periodontal and bone regeneration. Other natural polymers, however, have been developed and can be useful. Therefore, in this study, we aim to investigate the ability of four different natural polymers including collagen, chitosan, silk fibroin, and silk fibroin/gelatin hydrogel in promoting bone regeneration in vivo using rat calvarial bone defect. Two critical-sized defects (5-mm diameter) were created on the right and left calvarium of 8-week-old male Wistar rats. The rats were randomly assigned to one of the four treatment groups (n=3-4/group) and implanted with collagen, chitosan, silk fibroin, or silk fibroin/gelatin hydrogel scaffolds, respectively. Empty defect was used as a control. Four weeks after surgery, all animals were sacrificed and the calvarial bones were dissected for bone volume/total volume percentage (BV/TV%) measurement using micro-computed tomography, and subsequent histological analysis using hematoxylin & eosin and Masson's trichrome staining. The collagen scaffold resulted in significantly higher BV/TV than the other groups (p<0.05) with the greatest amount of new bone formation. There was no significant difference between other scaffolds and control group. Within the limitation of this study, collagen is the most effective scaffold in promoting bone regeneration in rat calvarial bone defects.