Differences in angiogenesis and osteogenic effects between autogenous bone and mixed bone in guided bone regeneration

Abstract

BACKGROUND: Angiogenesis is a key factor in the success of guided bone regeneration, but the impact of different bone graft materials on angiogenesis and osteogenic effects remains unclear. OBJECTIVE: To compare the angiogenesis and osteogenic effects of autologous bone powder and the mixture of autologous bone powder and artificial bone powder during guided bone regeneration. METHODS: Preoperative scanning of the jawbone data of New Zealand white rabbits using cone beam CT was performed to extract a rabbit jawbone model, which was then 3D printed to create a bone cutting guide plate. Twenty-one New Zealand white rabbits were used to construct a rabbit mandibular bone defect model. Each rabbit had two bone defect areas on both sides, one side was the autologous bone powder + artificial bone powder group, implanted with a mixture of autologous bone powder and artificial bone powder at a volume ratio of 1:1; the other side was the autologous bone powder group, implanted with autologous bone powder only. Angiogenesis and osteogenesis in the bone defect area were detected at 2, 5, 7, 14 days and 4, 8, 12 weeks after modeling. RESULTS AND CONCLUSION: (1) At 12 weeks postoperatively, the tissue morphology and angiogenesis of the autologous bone powder group and the autologous bone powder + artificial bone powder group were similar; (2) The number of vascular cross-sections in the autologous bone powder group showed a more significant upward trend at 2-7 days, while the trends of the two groups were similar in other periods; (3) At 8 weeks postoperatively, the distribution range of new bone in the autologous bone powder + artificial bone powder group was not as large as that in the autologous bone powder group. At 12 weeks, the continuity and density of bone tissue in both groups were better, close to normal bone tissue morphology; (4) At 8 weeks, the bone volume fraction of the autologous bone powder group was significantly higher than that of the autologous bone powder + artificial bone powder group (P < 0.05). At 12 weeks, there was no significant difference in bone volume parameters between the two groups (P > 0.05); (5) The results indicate that early angiogenesis and bone regeneration were more obvious with autologous bone powder implantation, but by 12 weeks postoperatively, the effect of mixed implantation of autologous bone powder and artificial bone powder was similar to that of autologous bone powder alone in repairing rabbit mandibular defects, indicating that with the progress of bone remodeling, the comprehensive effects of the two materials tend to be consistent.

1. Introduction

Guided bone regeneration (GBR) is a minimally invasive and efficient bone repair method that has gradually become a key approach for treating bone defects [1]. This technique utilizes a barrier membrane to prevent rapidly migrating cells from entering the defect area, creating a favorable environment for osteogenic cells and promoting bone healing [2]. In the field of oral and maxillofacial surgery, GBR is widely applied for reconstructing alveolar bone defects due to its maturity and reliability [3-4]. Current research on GBR mainly focuses on guided bone tissue, while morphological studies on early neovascularization during GBR are relatively scarce, and the growth pattern of blood vessels after bone graft material implantation remains unclear.

Early angiogenesis in the bone defect area is crucial for the success of GBR [5]. When osteoblasts are more than 100-200 μm away from blood vessels, they die due to hypoxia and nutrient deficiency [6-7]. Therefore, sufficient vascular ingrowth can supply blood, providing essential oxygen, nutrients, growth factors, and hormones to osteoblasts, while effectively removing metabolic waste, ensuring a stable and healthy cellular environment [8-9]. Moreover, during later bone tissue repair and regeneration, blood vessels are closely connected with newly formed bone tissue, and the ingrowth of new blood vessels provides a suitable microenvironment for the migration, proliferation, and differentiation of osteoprogenitor cells, promoting bone matrix synthesis and mineralization [10-11].

Bone graft materials, along with blood clots, serve as scaffolds for new blood vessels and bone tissue to 'climb' in the GBR defect area, guiding new bone regeneration to a predetermined height [12]. Currently, commonly used bone graft materials include autogenous bone, allograft bone, xenograft bone, and alloplastic bone [13]. Although autogenous bone is considered the gold standard for bone defect repair due to its osteoconductivity, osteoinductivity, and osteogenicity, it has limitations such as limited availability, the need for a second surgical site causing patient morbidity, and high resorption rate after transplantation, which restrict its clinical application [14]. Therefore, autogenous bone is often combined with bone substitutes in clinical practice [15]. This study selected Hai'ao bone powder, which is widely used clinically in China, as the artificial bone powder. Hai'ao bone repair material is made from bovine decellularized bone matrix, with a three-dimensional porous structure highly similar to human cancellous bone, exhibiting excellent biocompatibility and osteoconductivity, and playing an important role in maintaining a stable osteogenic environment and promoting neovascularization [16]. However, further research on the relationship between new blood vessels and bone powder is insufficient, and the impact of different bone graft materials on angiogenesis and osteogenesis remains unclear.