胰岛细胞抗体分型与胰岛细胞凋亡的实验研究

研究通过大量临床糖尿病病人胰岛细胞抗体（Islet Cell Antibody,ICA)检测，发现ICA阳性反应有两种完全不同的形态学表现；弥漫型ICA和边缘型ICA，经免疫组织化学双标技术鉴别。弥漫型ICA可同时有着染α细胞和β细胞，边缘型ICA则仅着染α细胞。这种只着染α细胞的ICA国内外尚未见有报道，为探讨其在糖尿病发病中所起的作用。选择1型糖尿病（1-DM）的弥漫型ICA和边缘型ICA各3例。另选正常3例作对照，用患血清分别以2、4、8小时三个时相与分离并贴壁生长的正常人胰岛细胞孵育后，进行原位细胞凋亡检测。结果发现，弥漫型ICA，边缘型ICA均可导致胰岛细胞产生凋亡，其中弥漫型ICA使β细胞及α细胞出现凋亡；边缘型ICA使α细胞产生凋亡，这一结果提示；糖尿病发病机制除与分泌胰岛素的β细胞有密切关系的经典途径之外，可能还与分泌胰高血糖素的α细胞存在某种关系。

EXPERIMENTAL STUDY ON THE ICA SUBSETS AND APOPTOSIS OF PANCREATIC ISLET CELLS

This study found that there were two conspicuous and differentpatterns in morphological distribution of the ICA (Islet Cell Antibody) positive reactive cells: the diffuse pattern and the peripheral pattern, this is on the basis of detecting a great deal of ICA from diabetes mellitus patients. Identification by double-labeling immunohistochemical techniques showed that both α-and β-cells in pancreatic islet were stained in the diffuse pattern, but only α-cells were stained in the peripheral pattern. These α-cells stained by only ICA were neither reported nor in China and abroad. In order to study the role of ICA on the onset of diabetes mellitus, we particularly Chose the sera from each 3 cases in the I-DM (type I-diabetes mellitus) patients with the diffuse and peripheral patterns ICA, and that of another 3 cases of normal persons as controls, and detected in situ cell apoptosis of isolated islet cells of normal persons after incubation with the patient's serum of three phases of 2、4、8 hours respectively. Our results showed that both diffuse pattern and the peripheral pattern could induce islet cells to occur apoptosis, among which the diffuse pattern induced more β cells and a small amount of α cells gaving rise to apoptosis; while the peripheral pattern mainly α cells. In conclussion, These results indicate that the pathogenic mechanism of diabetes mellitus may have some correlation with glucagon secution of α cells in addition to the classical mechanism of insulin secretion by β cells.