Myocardial connective tissue metabolism in response to injury. II. Investigation of the mucopolysaccharides involved in isoproterenol-induced necrosis and repair in rat hearts.

Myocardial necrosis was produced in rats by administering isoproterenol, and the increase in hexosamine-containing materials in the injured myocardium was investigated. Total hexosamine, galactosamine, neutral sugars, and uronic acids were determined on various fractions isolated from the hearts. Mucopolysaccharides were precipitated as the cetyl pyridinium chloride complex and fractionated according to their solubility in NaCl solutions. Of the hexosamine in the heart, approximately 50% was retained after proteolytic digestion and dialysis. Approximately one-fourth to one-third of the nondialyzable hexosamine was in mucopolysaccharides. The hyaluronic acid fraction of the mucopolysaccharides increased during the early edematous reaction observed in the hearts. The chondroitin sulfate fraction increased in conjunction with the beginning fibrinogenic processes and remained elevated during repair. There was evidence that the glycoproteins may be involved in the myocardial necrosis and repair. ADDITIONAL