Collagenase activity of cartilage in rats with experimental lathyrism: a model of bone diseases.

Collagenolytic activity was estimated in skin and joint cartilage of lathyritic rats by means of a biological assay. Lathyrism was induced by feeding beta-aminopropionitrile fumarate for six weeks, and the lathyritic state was confirmed by characteristic radiographic, histomorphologic and biochemical findings. Both tissues in lathyritic animals revealed significantly increased collagenolytic activity in comparison with those of the control animals. Studies were performed using ethylendiaminetetraactate and normal rat serum to determine the origin of inhibition of the collagenolytic system inhibition. Since both agents showed no inhibition of collagenolysis, the highly increased collagenolytic activity in lathyritic skin and joint cartilage appears not to be derived from polymorphonuclear cells nor from serum, but from the tissue itself. Elevation of collagenase activity may be important with respect to the increased neutral salt solubility of collagen and hydroxyproline excretion observed in experimental lathyrism.