Mast cells in areas of experimental bone resorption and remodelling.

Investigation on the presence of mast cells in the remodelling adductor longus-pectineus exostosis, induced by either surgical or BAPN stimulation, and in the healing fracture callus, demonstrated that mast cells were not pathognomonic for the bone lesions of BAPN-treated animals. Numerous mast cells were found in association with the endosteum of the skeletal trabeculae and throughout the new marrow replacing the trabeculae of the experimental lesions, with no increase in the mast cell numbers in the original marrow of the femoral shaft. Mast cells were not present in areas of cartilage resorption, but they were present when resorption and remodelling of the endochondral trabeculae commenced. It is surmised that mast cells play a role in connective tissue resorption and remodelling by supplying a factor necessary for the release of hydrolytic enzymes.