大鼠心脏移植后淋巴细胞5种免疫分子表达的变化

The expression of 5 kinds of immune molecules of rat peripheral leucocytes after heart transplantation

目的 :观察大鼠异体异位心脏移植术后不同时间点 ,淋巴细胞相关免疫分子的表达水平、供心存活率及心肌组织的病理学改变 ,探讨免疫排斥反应的相关时间进程。方法 :分别经供体SD大鼠的心脏主动脉、肺动脉与受体Wistar大鼠的腹主动脉及下腔静脉吻合 ,进行异位心脏移植术。于术前及术后不同时间点 ,取血分离淋巴细胞。用流式细胞仪分别检测淋巴细胞上CD4、CD8、IL 2R、ICAM I和MHC II类分子的表达水平。对供心心肌组织进行常规病理学检查。结果 :于移植后2 4h ,只有MHC II类分子的表达水平增加 ,CD4、IL 2R和I CAM I的表达水平降低 ,CD8无改变。术后 72h,CD4、CD8及IL 2R的表达增加 ,其中CD8和IL 2R达峰值。术后 7～ 10d ,除CD4的表达继续增加外 ,其他 4种免疫分子的表达水平逐渐降低。术后不同时间点移植心脏的存活率分别为 :10 0 % (2 4h)、85 .7% (72h)、16 .7% (7d)、0 (10d和 12d)。病理学检查显示 ,移植后 2 4h ,心肌组织无明显的病理学变化 ,术后 3d ,7只大鼠中 4只出现ⅠA级及以上病理改变。术后 7d ,6只大鼠全部发生Ⅱ级以上的病理学变化。结论 :大鼠心脏移植后的 2 4h内 ,外周血淋巴细胞为以MHC II分子表达为主的抗原识别、呈递期 ,并伴有一过性免疫功能降低 ;术后 2 4～ 72h为T细胞活化期 。

AIM: 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. METHODS: Donor’s heart derived from SD species rat was transplanted into the abdomen cavity of Wistar species 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. RESULTS: 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 gradeⅠ A pathological change. Grade Ⅱ and above grade II pathological changes were observed in all 6 grafts at the 7th day after operation. CONCLUSION: 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.