Histological and immunohistochemical evaluation of the effect of local exogenous application of VEGF on bone healing (experimental study in rat)

Abstract

Background: The repair of bone defects remains a major clinical orthopaedic challenge. Bone is a highlyvascularised tissue reliant on the close spatial and temporal connection between blood vessels and bone cells tomaintain skeletal integrity. Angiogenesis thus plays a pivotal role in skeletal development and bone fracture repair.The role of angiogenic and osteogenic factors in the adaptive response and interaction of osteoblasts andendothelial cells during the multi step process of bone development and repair will be highlighted in this study. Thisstudy aimed to identify the role of local exogenous vascular endothelial growth factor in bone healing and toanalyze the expression of VEGF by immunohistochemistry in created bone defect after application with differentbiomaterials in a rat model.Materials and methods: In this experimental study eighteen male Albino rats, weighing (300-400) gram, aged (6-8)months were used and maintained under control conditions of temperature, drinking and food consumption. Theanimals were subjected for a surgical operation of medial sides of both tibiae bone ( right side was considered asexperimental site ,while left be the control one), in control group the bone defect treated with local application of1μm of normal saline, while experimental treated with local application of 1μm of VEGF .The rats were sacrificed at3,7,10 days after surgery(six rats for each period). Bone healing was histologically examined withimmunohistochemical localization of VEGFResults: Bone defect treated with local application of VEGF shows an early osteoid tissue deposition with high cellcount for osteoblast, osteocyte and osteoclast. Immunohistochemical evaluation for VEGF by stromal cells, reportedto be higher with significant difference in VEGF group in comparison to control.Conclusion: The study illustrated that low application of VEGF could be an effective therapeutic expression for boneinjuries; these data are promising for a possible future clinical usage