Cissus quadrangularis L. hexane extract infused glyoxal cross-linked chitosan-collagen scaffold elicits early osteoinduction

Background

The induction of osteoblast activity by natural materials would possibly eliminate toxicity concerns and can serve as a better approach for regenerative drug development studies. Cissus quadrangularis Linn. (CQ) extract is a good source of β-sitosterol, phytoestrogens, β-carotene, flavonoids, etc., and aqueous CQ extract is traditionally used for bone fracture healing.

Purpose

This study presents histopathological evidence for the significant osteoinductive potential of CQ hexane extract in a mechanically reinforced natural scaffold in rat models of critical sized calvarial defects.

Study design

To validate the bone regeneration potential of glyoxal cross-linked, mechanically reinforced, CQ hexane extract-infused chitosan-collagen scaffold (CHCOHE) in vivo in a critical-size rat calvarial defect model. (Controls: SHAM (defect without scaffolds) operated control and chitosan collagen scaffold (CHCO)).

Materials and methods

Glyoxal cross-linked chitosan-collagen scaffold is prepared as per the procedure we have reported recently. A critical-size defect (6 mm diameter × 2 mm thickness) was made at the dorsal calvarium using a trephine burr. The 6 mm critical sized calvarial defects were created and the scaffolds (CHCOHE and CHCO) were implanted into the defect. SHAM served as a negative control. The animals were sacrificed after 4 and 12 weeks to analyze the extent of new bone formation.

Results

Histopathological evaluation of CHCOHE implanted critical-size calvarial defect in rats indicates the presence of osteoblast cells, neovascularization along with evidence of scaffold degradation by giant cells after 4 weeks. Continual examination designates the formation of mature lamellar bone formation at 12 weeks both in the middle and periphery regions of the defect site. Although CHCO scaffold alone also promoted healing, the quantitative assessment of new bone formation is significantly greater for CHCOHE than CHCO group. SHAM-operated controls did not elicit any new bone formation.

Conclusion

This study highlights the high competency of CQ hexane extract (even at a very low concentration) and the efficacy of glyoxal cross-linked chitosan-collagen natural scaffold as a potential osteoinductive biodegradable scaffold for repairing critical-size bone defects.