The possible role of the fibroblast in granuloma‐induced bone resorption in the rat

Granulomas were produced over the calvaria of rats by injection of a mixture of turpentine and peanut oil. The granulomas induced localised areas of bone resorption and these resorptive lesions were examined at the fine structural level. A close association was found between osteoclasts and fibroblasts at resorbing surfaces. Furthermore, fibroblasts but not osteoclasts were observed to engulf and phagocytose bone collagen fibrils. It is suggested that the fibroblast either alone or in collaboration with the osteoclast is involved in the destruction of bone collagen during chronic inflammatory disorder of bone.