甘氨酸经内质网途径对严重烧伤大鼠心肌保护效应及机制研究

The prevention of myocardial damage at early phase is effective to alleviate ischemic and anoxic damage to organism from severe burn injury. The previous study from author indicated that myocardial cell has glycine receptors on its membrane, which can be bind with glycine and exert preventive effects for the cell when hypoxia occurs. Furthermore, it was found under confocal laser scanning microscope that fluorescin-labeled glycine accumulated on endoplasmic reticulum of myocardial cell. Therefore, the effect of glycine, in preventing myocardial cell by binding to its receptor and altering membrane potentials of endoplasmic reticulum via P13K/Akt signal transduction pathway, deserves to be discussed. On the basis of the previous results, the aim of the current study is two-fold. First, to determine the presence of glycine receptors on endoplasmic reticulum of myocardial cells, using immunocytochemical method, receptor protein and radioligand-binding assay, RNA interference and other experimental approaches. Second, to research the mechanism on which glycine and its receptor activate P13K/Akt signal transduction pathway in endocytoplasmic reticulum. The study was to explain the mechanisms of preventive effects of glycine for myocardial cell, which has significance in preventing and alleviating ischemic and anoxic damage, and thereby decreasing cardiac complications of burn injury and improving patients' recovery rate.

早期心肌损害的防治是减轻严重烧伤缺血缺氧的有效策略之一。申请者的前期研究表明，心肌细胞膜存在甘氨酸受体，缺氧后甘氨酸与其在心肌细胞膜上的受体结合，发挥了其保护作用。同时经前期的预实验发现，采用量子点标记的甘氨酸（绿）与内质网（红）在激光显微镜下共定位显示进入心肌细胞的甘氨酸大量聚集在内质网，提示我们在心肌细胞内质网是否也存在甘氨酸受体？如果存在，甘氨酸对心肌的保护作用是否通过与其在内质网膜上的受体结合后，改变内质网膜电位，进而发挥其下游细胞保护效应尚待研究。本项目在以往研究基础上，拟采用免疫细胞化学法、受体蛋白测定、放射配体结合测定法以及RNA干扰技术等多种方法，确证心肌细胞内质网膜甘氨酸受体的存在，并探讨具体是何种途径激活PI3K／Akt信号转导途径来保护心肌细胞。旨在阐明甘氨酸对心肌细胞保护作用及其多种作用机制，对防治和减轻心肌缺血缺氧，减少内脏并发症，提高治愈率均有重要意义