Glycosaminoglycan Changes in Healing Myocardial Infarction

Abstract
Experimental myocardial infarcts were produced in mongrel dogs by ligation of the circumflex coronary artery. Surviving animals were killed at times varying from 1 h to 90 days after injury. Damaged and undamaged areas of the heart were immediately removed, minced and freeze-dried. Samples were digested with papain and the glycosaminoglycans were separated by cellulose acetate electrophoresis and further identified by chondroitin AC lyase and chondroitin ABC lyase. The most striking change was a 30-fold increase of the chondroitin-4-sulfate fraction in the injured tissue after 10 days with significant elevations of this component 3 days post-injury. The increased uronic acid together with the electrophoretic distribution of glycosaminoglycans also indicated increased hyaluronic acid and dermatan sulfate fractions in injured tissue. These dramatic changes in glycosaminoglycan composition were supported by morphological studies which demonstrated a brisk fibroblastic activity and a large increase of P.A.S. [periodic acid-Schiff] staining material in the injured tissue at 10 days post-injury. By 90 days, the chondroitin-4-sulfate was much decreased but was still elevated as compared with uninjured tissue.