转基因表达KLK1抵抗压力负荷引起的心室重构

Transgenic Expression Klk1 Resists Ventricular Remodeling Caused By Pressure Load

目的 KLK1基因对高血压具有保护作用,KLK1在心脏中也有所表达,但目前对KLK1基因在心肌中的作用所知甚少。本研究通过建立KLK1基因转基因小鼠,在压力负荷的条件下,研究KLK1对心室重构的作用。方法把人KLK1基因插入鸡β-肌动蛋白启动子下游,构建转基因表达载体,显微注射法建立C57BL/6JKLK1转基因小鼠,PCR鉴定转基因小鼠基因型。采用Western Blot鉴定KLK1在心脏、大血管和肾脏中的表达筛选高表达转基因品系。用无创血压仪测量血压,利用超声影像分析技术和病理学观察转基因小鼠心脏结构与功能改变。结果建立了在心脏、肾脏和大血管壁高表达KLK1基因的转基因小鼠。在正常情况下,与同窝转基因阴性小鼠相比,转基因小鼠心脏结构和功能无显著变化。主动脉缩窄术后1个月,由于压力负荷的存在,同窝阴性小鼠左心室壁厚病理性肥厚,而转基因表达的KLK1可明显地抑制左心室壁肥厚的进程;主动脉缩窄术后2个月,同窝阴性小鼠心脏进入到病理性扩张阶段,KLK1也表现出对心肌病理性扩张的抑制,同时,组织学染色显示KLK1转基因小鼠心肌肥厚与纤维化程度减弱。结论转基因表达KLK1可抵抗压力负荷引起的心室重构。

Objective KLK1 gene is involved in the protection of hypertension. KLK1 was found also expressing in tissue of heart, but the role of KLK1 gene in heart is little known yet. In the current paper, we establish a KLK1 gene transgenic mouse line and study the effect of KLK1 gene in ventricular remodeling using this transgenic mouse model. Methods The transgenic vector was constructed by inserting the human KLK1 gene into the down stream of chicken β-actin promoter. The transgenic mice were created by the method of microinjection. The genotype of transgenic line was identified by PCR and the expression level of target gene was determined by Western blot. Blood pressure was measured by noninvasive blood pressure meter. The structural and functional changes of the heart were analyzed with echocardiography and light microscopy observation. Results One line of C57BL/6J transgenic mice with high levels of KLK1 expression in heart, kidney and great vessels tissues was established. In normal condition, the transgenic expression of KLK1 did not change the structure and function of the heart obviously. After thoracic aorta constriction for a month, the non-transgenic mice showed left ventricular pathologic hypertrophy caused by pressure load, however the transgenic expression of KLK1 inhibit the process of left ventricular pathologic hypertrophy significantly. After thoracic aorta constriction for two months, the non-transgenic mice showed pathologic dilatoriness, the transgenic expression of KLK1 also inhibit the process. Meanwhile myocardial hypertrophy and fibrosis were attenuated in KLK1 gene transgenic mice observed in histological staining. Conclusion Transgenic expression KLK1 resists ventricular remodeling caused by pressure load.