非T细胞来源细胞因子在小鼠心脏移植急性排斥反应模型中的表达

Expression of non-T cell derived cytokines in acute rejection after heart transplantation: experiment with mouse model

目的研究急性排斥反应性细胞因子在小鼠心脏移植中的表达状况,进一步阐明器官移植急性排斥反应的复杂发生机制。方法采用C57BL/6和Balb/c近交系小鼠,建立小鼠腹腔异位心脏移植模型。随机分为Balb/c-Balb/c同基因对照组(A组)和C57BL/6-Balb/c急性排斥反应组(B组)两组,每组26只。分别于移植术后1、3、5、7 d各处死5只小鼠留取移植心脏标本,采用RT-PCR及W estern印迹方法动态检测组织中IL-15、IL-2、TNF-α及IFN-γ的表达状况,同时行HE染色检测。另外,A、B两组各保留6只小鼠设为亚组,观察移植心脏存活时间。结果A组移植心均获长期存活(>100 d),B组移植心存活时间为8.0 d±0.9 d(t=251.95,P<0.01)。A组各个时间点移植心均未发现排斥现象,B组术后第3天开始出现排斥反应。A组各时间点IL-15 mRNA与TNF-αmRNA呈弱表达,IL-2 mRNA与IFN-γmRNA无表达。B组IL-15 mRNA、TNF-αmRNA、IL-2 mRNA及IFN-γmRNA均明显升高,于第5天达到高峰。A组各时间点可见IL-15、TNF-α、IFN-γ和IL-2蛋白的低水平表达;B组IL-15与IL-2自术后第3天始、TNF-α与IFN-γ自术后第1天始,蛋白表达水平开始升高。结论多种细胞因子,包括非T细胞来源细胞因子,参与了同种异体急性排斥反应的发生。

Objective to investigate the expression of non-T cell derived cytokines in acute rejection after heart transplantation. Methods The hearts of 26 C57BL/6 mice were transplanted into the abdominal cavities of 26 Balb/c mice （acute rejection group ）. The hearts of 26 Balb/c mice were transplanted into the abdominal cavities of another 26 Balb/c mice （ syngeneic control group ）. After the operation, heart beat was felt with finger at the abdomen every day to determine the survival of the transplanted heart. One, three, five, and seven days after the operation the transplanted hearts were taken out from 5 mice in each group respectively to undergo microscopy. RT-PCR was used to detect the mRNA expression of these cytokines： interleukin （IL）-2, IL-15, tumor necrosis factor （TNF）-α, and interferon （IFN）-γ. Western blotting was used to detect the protein expression of these cytokines. Six mice in each group, totally 12, were used to observe the survival time of transplanted heart. Results The mice of the control group recovered more rapidly in comparison with the nice of the acute rejection group. The survival times of the transplanted hearts of the control group were all longer than 100 days, significantly longer than those of the acute rejection group （7-9 days, P 〈0.01 ）. No sign of acute rejection was found in the hearts of the control group, and significant lymphocyte infiltration was seen in the myocardium of the acute rejection group 3-7 days after the operation. In the control group, no mRNA expression of IL-2 and IFN-was seen at any time-point, and IL-15 mRNA and TNF-α mRNA were expressed at low level at any time-point. However, in the acute rejection group the mRNA expression of IL-2, TNF-α, and IL-15 could be detected since the first day post-operatively and peaked on the day 5, but the mRNA expression of IFN-γ could be detected and peaked only on the 5 th post-operative day. The mRNA expression levels of these 4 cytokines atany time point of the acute rejection group were all significantly higher than those of the control group （ P 〈 0.01 or P 〈 0.05 ）. The proteins of the 4 cytokines were all expressed at low level at any time point in the control group. However, in the acute rejection group the protein expression levels of IL-15 and IL-2 began to increase since the third day after operation and the protein expression levels of TNF-α and IFN-γ began to increase since the first day after operation. Conclusion Many cytokines, including T cell derived and non- T cell derived cytokines, are involved in the pathogenesis of acute rejection after allogeneic organ transplantation.