Effect of herbal extracts on bone regeneration in a rat calvaria defect model and screening system

Abstract

Objectives: The aim of this study was to evaluate the effects of herbal extracts on bone regeneration. Two known samples were screened.

Materials and methods: We previously established a rat calvaria defect model using a combination of collagen scaffold and herbal extracts. An 8 mm diameter trephine bur with a low-speed dental hand piece was used to create a circular calvaria defect. The experimental group was divided into 4 classifications: control, collagen matrix, Danshen with collagen, and Ge Gan with collagen. Animals in each group were sacrificed at 4, 6, 8, and 10 weeks after surgery, and bone regeneration ability was evaluated by histological examination.

Results: Results revealed that both Danshen and Ge Gan extracts increased bone formation activity when used with collagen matrix. All groups showed almost the same histological findings until 6 weeks. However, after 6 weeks, bone formation activity proceeded differently in each group. In the experimental groups, new bone formation activity was found continuously up to 10 weeks. In the Danshen and Ge Gan groups, grafted materials were still present until 10 weeks after treatment, as evidenced by foreign body reactions showing multinucleated giant cells in chronic inflammatory vascular connective tissue.

Conclusion: Histological analyses showed that Danshen and Ge Gan extractions increased bone formation activity when used in conjunction with collagen matrix.

Keywords: Bone regeneration; Danshen; Ge Gan; Herb extract; Rat calvaria defect.

Fig. 1. Representative H&E sections depicting the new bone formation at 4, 6, 8, and 10 weeks for each groups (H&E staining, A–P: ×200, inset: ×1,000). (OB: osteoblasts [double arrows], GM: grafted material, OS: osteoid)

Fig. 2. Representative H&E section depicting healing process in defect area at 10-week trial (H&E staining, A–D: ×400). A, B. Fibroblastic dense collagen tissue without inflammation in control and collagen group. C, D. Grafted materials (GMs) are surrounded by foreign body reaction showing multinucleated giant cells in chronic inflammatory vascular connective tissue in Danshen and Ge Gan groups, respectively.