Generation of a femoral non-union model utilizing phosphate deficient mice

Abstract

Fracture non-unions occur when the biological process of fracture healing fails to complete. The events that occur in the fracture healing process of mice are similar to the events that occur in humans. Inorganic phosphate is essential for maintaining healthy bones. In this study mice are placed on a phosphate deficient diet two days prior to fracture of the right femur. The mice were then maintained for 5, 10, 15, and 20 days of restricted diet and compared to control animals. The progression of fracture healing was assessed by plain film x-ray radiography and biological healing was assessed by analyzing mRNA expression for marker genes for cartilage and bone formation. Initial removal of the phosphate from the diet will delay the completion of the normal fracture healing process and produce delayed union with progressively longer periods of delay commensurate with the period of dietary restriction. When phosphate is re- introduced to the diet, the fracture healing process is reinitiated; however, progressively longer periods of times are needed to achieve union based on the period of initial phosphate restriction.