Immunohistochemically Localization of Bone Morphogenetic Proteins 4 in Bone Defect Healing Treated by Local Application of Hydroxyapatite/Beta-Tricalcium Phosphate and Hyaluronic Acid in Rats

Abstract Background: Bone naturally has the ability to regenerate as part of the healing process after injury. There are specific signaling molecules that can strictly control and organize these cellular events. Some of these molecules are bone morphogenetic proteins (BMP). Objectives: The aim of this study was to estimate the localization of BMP4 in the healing of bone defects treated by hydroxyapatite/beta-tricalcium phosphate (HA/β-TCP) and hyaluronic acid (HY). Materials and Methods: Thirty-two male albino rats were used in this experimental study. Intrabony defects of about (2.5 mm) in width and (2.5 mm) in depth were created in the distal side of both the right and left femurs bones of each rat. Animals were divided into four groups, a control group was leaving to heal spontaneously, experimental group 1 received HY gel, experimental group 2 received HA/β-TCP materials, and experimental group 3 received a combination of HA/β-TCP and HY in a bony defect. The sacrifices of animals were performed after 2 and 4 weeks. Immunohistochemical tests for the localization of BMP4 were performed on all bone specimens. Results: Immunohistochemically localization of BMP4 revealed that using HA/β-TCP and HY boosted the positive expression of BMP4 by bone cells, particularly in 2 weeks intervals. Conclusions: The utilization of HA/β-TCP and HY when treating bony defects was accelerating bone healing by increasing the expression of BMP4 by bone cells.