结缔组织生长因子在大鼠心脏移植慢性排斥反应中的表达及意义(英文)

Role and significance of connective tissue growth factor expression in a rat model of chronic heart allograft rejection

背景：慢性排斥反应限制了心脏移植患者的长期存活．有报道结缔组织生长因子因其与细胞增殖和胶原合成有关，似乎参与了此过程。目的：假设结缔组织生长因子在大鼠心脏移植慢性排斥反应中发挥作用，实验拟验证其表达与心脏慢性排斥反应病理过程的关系。设计、时间及地点：随机对照动物实验，于2007—04／08在中南大学湘雅二医院动物实验中心完成。材料：取20只Wistar大鼠作为供体，20只SD大鼠作为受体，制作腹部异位心脏移植模型20例次；另选择10只Wistar大鼠作为对照。方法：大鼠腹部异位心脏移植术后，给予环孢素A、霉酚酸酯和甲泼尼龙三联免疫抑制治疗。移植后2．8周分别按随机数字表法麻醉后处死10只受体大鼠．取心脏；10只Wistar大鼠心脏作为对照。主要观察指标：采用苏木精-伊红染色及Van Gieson染色观察心肌病理形态、心肌血管密度及心脏血管狭窄程度：并进行心肌纤维化半定量评分。采用免疫组织化学法检测心肌组织结缔组织生长因予蛋自的表达：并分析结缔组织生长因子表达与慢性排斥反应过程中心肌血管病变及纤维化的相关性。结果：①术后8周移植心脏血管狭窄程度、心肌纤维化评分及结缔组织生长因子蛋白表达量明显高于术后2周及正常心脏（P〈0．05-0．01）；术后8周移植心脏血管密度低于正常心脏（P〈0．05）；结缔组织生长因子在正常心脏基本没有表达。②心肌组织结缔组织生长因子蛋白表达灰度值与心肌纤维化、血管狭窄程度均呈负相关（r=0．734，-0．713，P〈0．01），表明结缔组织生长因子表达与心肌纤维化及血管狭窄程度呈正相关。结论：结缔组织生长因子在有心肌血管病变的移植心畦心肌组织中表达增强，其表达与心肌纤维化和心肌血管病变形成有关，在心肌移植排斥反应的病理过程中起重要作用。

BACKGROUND： Chronic rejection limits the long-term success of cardiac transplantation and the underlying causes of the disease are unknown. Connective tissue growth factor （CTGF） is considered as a mitogenic and chemotactic factor for fibroblasts and is associated with cell proliferation and collagen synthesis. OBJECTIVE： To evaluate the role and significance of expression of CTGF in rat chronic rejection heart allografts. DESIGN, TIME AND SETTING： A randomized controlled animal experiment was performed at the Laboratory Animal Center of the Second Xiangya Hospital between April and August 2007. MATERIALS： Twenty Wistar rats serving as donors and twenty Sprague-Dawely （SD） rats serving as recipients were included. An additional 10 Wistar rats were included as controls. METHODS： After intra-abdominal heterotopic heart transplantations, rats received cyclosporine A, mycophenolate, and methylprednisolone immunosuppression. Ten recipient rats were anesthetized and sacrificed for heart harvesting at 2 and 8 weeks postoperation, respectively. MAIN OUTCOME MEASURES： Coronary vessel density, fibrosis grade, and intimal occlusion were observed by hematoxylin-eosin staining and Van Gieson staining. Myocardial fibrosis was semi-quantitatively scored. CTGF expression was detected by immunohistochemistry. The associations between CTGF expression and allograft fibrosis and CAV formation were analyzed. RESULTS： Allografts harvested at 8-week post-surgery showed more obvious coronary intimal proliferation, fibrosis and higher CTGF expression compared with the 2-week allografts and the contlols （P 〈 0.05-0.01） while the cardiac artery density was lower than the control group （P 〈 0.05）. However, the control group in our study showed negligible CTGF expression. There were strong negative correlations between the gray value of CTGF protein expression and cardiac fibrosis and coronary intimal occlusion （r = -0.734, -0.713, P 〈 0.01）, demonstrating that CTGF protein expression was positively correlated with cardiac fibrosis and coronary intimal occlusion. CONCLUSION： CTGF is expressed in cardiac myocyte with CAV. The increased expression of CTGF in the cardiac allograft is associated with CAV development and fibrosis formation and is involved in the pathogenesis of chronic heart rejection