Bone remodeling in puppies with experimental rickets.

Abstract

Abstract Biochemical and histological changes characteristic of rickets were produced in puppies fed two low-calcium diets, both deficient in vitamin D. Three criteria of surfaces undergoing bone formation—lamellae of bone of low density running parallel to a smooth surface seen microradiographically, high concentration of tetracycline labeling, and surfaces covered by osteoid—appear to be correlated in normal animals; this correlation was lost in the rachitic puppies. In the rachitic puppies the osteoid borders were wider and the amount of new tissue deposited (bone formation) during the test period was reduced. Internal surface of bone covered with osteoid may not be susceptible to resorption. This hypothesis was supported by the persistence of old periosteal bone and the decrease in number of secondary osteons.