Temperature-sensitive, 1- bromoheptafluorooctane-containing hydrogels in repairing bone defect in rabbits

Abstract

Bone defects are common consequences of bone trauma. The application of biomaterials as tissue scaffolds combined with oxygenating agents, as bone regeneration promoters, is an interesting strategy to improve bone repair. The present study aimed to investigate the potential of a temperature-sensitive hydrogel containing 1-bromoheptafluorooctane in repairing rabbit bone defects and its possible mechanism of action. Bone defects were surgically created in the femoral condylar of New Zealand White rabbits. The animals were divided into three groups: A) treated with the temperature-sensitive hydrogel containing 1-bromoheptafluorooctane with oxygen release; B) treated with the temperature-sensitive hydrogel containing 1-bromoheptafluorooctane without oxygen release; and C) received no treatments. At four and 12 weeks post-operation, the specimens from all groups were collected. The new bone formation was studied by morphological observation, X-ray, Micro-CT, Masson’s trichrome, and CD31 immunohistochemical staining. At 12 weeks post-operation, the bone defects were completely healed in groups A and B, while a major bone defect was still present in group C. Micro-CT showed that TMD, BVF, Tb.Th and Tb.N in group A were significantly higher compared to the other groups at each time point post-operation. The SMI value of group A showed a significant difference from the other groups at 12 weeks post-operation. The number of micro-vessels in group A was significantly higher compared to the other groups at four and 12 weeks post-operation. The oxygenating temperature-sensitive hydrogel containing 1-bromoheptafluorooctane could effectively promote new bone formation while increasing tissue vascularization, highlighting a good clinical application prospect.

Keywords

• Bone defect
• Bone tissue engineering
• 1-bromoheptafluorooctane
• Temperature-sensitive hydrogel
• New Zealand white rabbit