RESUMEN
Objective To study the expression of intercellular adhesion molecule-1 (ICAM-1 ) in the rat cardiac heterotopic allo- grafts and the effect of cyclosporin A on prevention of allograft rejection. Methods Heart transplantated animals were divided into three groups: Group Ⅰ(control), Group Ⅱ(CsA 7. 5mg/kg B W, daily) and Group Ⅲ(CsA l5mg/kg B W, daily). Acute cardiac rejection grade was valued by the standrd of ISHLT(1990 ). Immunohistochemistry was performed to analyze the expression of ICAM-1 in heart grafts and donor aorta segments. Results After heart transplantation, it was found that from day 1 to 3, there was sligtly inflammatory infiltratiation, the rejection was graded 1A of 1B, But from day 11 to 12, there were disseminated inflammation and cardiac necrosis with serous hyperemia, exutation, edema, acute vasculitis and myocarditis. The rejection grade was 3B or 4, and could be reduced 1to 2. 5 grades by administration of CsA. It was also found that both in heart graft and donor aorta segments the expression of ICAM-1 on the endothelium cells, infiltrated lymphocytes was clearly increased. It was time-dependent and could be down-regulated by administra- tion of CsA. On Day 1 and Day 3 the suppressing function of CsA on expressing of ICAM-1 showed singificant dosage-dependent. But from Day 7 to Day 11, it appeared dosage- independent. Conclusiou Trea tment with CsA is an effect ive methed to down- regulate I - CAM-1 expression and could reduce the lympphocyte migration and filtration. These results may explain, in part, the mechanism of CsA reducing acute rejection in a rat cardiac transplantation medel.