Induced acute ischaemia in dog bones: age-related effects.

Acute ischaemia was induced in the lower limb of both growing and adult dogs by injection of the femoral artery with a suspension of carborundum and ground glass in physiological saline. Besides the gangrenous process observed in all the animals, the most striking finding was the quite different reaction between the two groups of dogs. The ischaemic bones of the growing dogs presented a tremendous periosteal woven bone formation and, to a lesser extent, an endosteal one. This new bone apposition was accompanied by compact bone resorption. The osteogenic phenomenon involved in some degree metaphyseal and epiphyseal intertrabecular spaces. This process took place from the 12th day of experiment and was never observed in the adult dogs. It can be interpreted as the result of the transitory periosseous vascular system activity originating from the surrounding soft tissues. Furthermore, the physiological inactivity of the periosteal osteogenic layer in the adult animals is probably responsible for the absence of osteogenic reaction in this experimental group.