[The expression of 5 immune molecules on rat peripheral leucocytes after heart transplantation]

To observe 5 kinds of immune molecule expressions on rat peripheral leucocytes at varying time points after ectopic heart transplantation and explore the mechanism of acute rejection reaction.

Donor's heart derived from SD rat was transplanted into the abdomen cavity of Wistar rat by anastomosis of donor's aorta and pulmonary artery to recipient's abdominal aorta and inferior-venacava for establishing coronary perfusion. Before and after transplantation, peripheral leucocytes were isolated from venous blood and labelled with the monoclonal antibodies(mAbs) against CD4, CD8, IL-2R, ICAM-I and MHC-II molecules, respectively. The these molecule levels were assessed by flowcytometry. Simultaneity, graft's pathological changes and their survival rate were observed.

At 24 hours after transplantation, MHC-II molecule expression was increased, while expressions of CD4, IL-2R and ICAM-I were significantly decreased, but CD8 expression had no change. At 72 hours after operation, the expressions of CD4, CD8 and IL-2R increased and expressions of CD8 and IL-2R reached to peak. At 7-10 days after operation, except that CD4 expression increased continuously, the expressions of 4 other molecules decreased gradually. The survival rate of graft at varying times after operation were 100%( 24 h), 85.7%(3 days), 16.7%(7 days) and, 0 (10 and 12 days), respectively. Pathological examination showed that there was no notable pathological change in cardiac muscle tissue. At the third day after operation, 4 out of 7 transplanted hearts had only grade I A pathological change. Grade II and above grade II pathological changes were observed in all 6 grafts at the 7th day after operation.

These data indicate that graft rejection reaction begin to appear in first 72 hours, and effector phase of the reaction appear mainly within 3-7 days after heart transplantation.