小鼠心脏Telocyte间质细胞的存在与特点

Existence and features of Telocyte cells in the mouse heart

背景:有研究发现Telocyte间质细胞可能在急性心肌梗死、房颤、心脏瓣膜病及心肌淀粉样变性等心脏疾病发挥作用,但其机制尚不清楚,相关心脏Telocyte间质细胞的基础研究具有重要的临床价值。目的:多种技术探讨小鼠心脏Telocyte间质细胞的存在与特点。方法:选择10 d-10周龄昆明小鼠59只(由福州吴氏实验动物中心提供),以胃肠道Cajal间质细胞及膀胱Telocyte间质细胞为对照组进行对比研究。ACK2(c-kit单克隆抗体)作为指标,进行心肌组织免疫组化染色(n=13);体外心脏Telocyte间质细胞分离与培养(n=41),之后进行细胞免疫荧光激光共聚焦显微镜以观察细胞形态及突起情况;透射电镜(n=5)观察细胞超微结构。结果与结论:(1)免疫组化染色显示在小鼠胃肠道、膀胱组织发现c-kit阳性表达产物,心脏组织未发现c-kit阳性表达,体外原代培养发现c-kit阳性表达;(2)免疫荧光激光共聚焦显微镜和透射电镜观察均发现心脏Telocyte间质细胞,镜下心脏Telocyte间质细胞嵌插于心肌纤维束间及毛细血管周围,胞体呈梭形或不规则形,心室Telocyte间质细胞突起与毛细血管间发现长条形"致密物质"。与对照组比较胞体大小、突起数量无显著性差异(P> 0.05),但细胞突起长度有显著性差异(P <0.05);(3)结果提示,利用原代培养、免疫荧光及透射电镜技术确定小鼠心脏存在c-kit阳性表达的Telocyte间质细胞,其胞体大小、突起数量与胃肠道Cajal间质细胞或膀胱Telocyte间质细胞类似;心室Telocyte间质细胞突起最长,心房Telocyte间质细胞突起最短,心室Telocyte间质细胞突起与毛细血管间存在紧密连接。

BACKGROUND:Studies have found that Telocyte interstitial cells may play a role in heart diseases,such as acute myocardial infarction,atrial fibrillation,valvular heart disease and myocardial amyloidosis,but the mechanism is unclear.The basic research of cardiac Telocyte interstitial cells is of important clinical value.OBJECTIVE:To explore the existence and characteristics of Telocyte interstitial cells in the mouse heart.METHODS:Fifty-nine Kunming mice aged from10days to10weeks(provided by Fuzhou Wu’s Experimental Animal Center in China)were chosen.The gastrointestinal tract Cajal interstitial cells and bladder Telocyte interstitial cells were used as controls.ACK2(c-kit monoclonal antibody)was used as an indicator for the immunohistochemical staining of myocardial tissue in13mice.Cardiac Telocyte cells from another41mice were isolated,cultured in vitro and observed for cell morphology and protrusion under immunofluorescence laser confocal microscope.Ultrastructure of Cajal and Telocyte interstitial cells from the remaining five mice was observed by transmission electron microscopy.RESULTS AND CONCLUSION:(1)Positive expression of c-kit was found in the gastrointestinal and bladder tissues by immunohistochemical staining,but not in the cardiac tissues.However,in vitro cultured cells were positive for c-kit.(2)Under the immunofluorescence laser confocal microscope and transmission electron microscope,the cardiac Telocyte cells with spindle or irregular bodies were discovered in myocardial fibers or around the capillaries,and dense strips were found between cell protrusions from cardiac Telocyte cells and the capillaries.There was no difference in the shape of cell body and the number of cell protrusion compared with the control group,but a significant difference in the length of cell protrusions was found(P<0.05).In conclusion,the presence of Telocyte cells with positive expression of c-kit in the mouse heart is confirmed by primary culture,immunofluorescence staining and transmission electron microscopy.The body size and number of cell protrusions are similar to those of gastrointestinal tract Cajal interstitial cells or bladder Telocyte interstitial cells.Ventricular Telocyte interstitial cell protrusion is the longest,atrial Telocyte interstitial cell protrusion is the shortest,and ventricular Telocyte interstitial cell protrusion is tightly connected with the capillaries.