Role of adhesion morecule between glomerular epithelial cells and basement membrane, and cytoskeleton in proteinuria

蛋白尿是肾小球肾炎的标志，可引起进行性肾功能不全。目前认为尿蛋白排泄的机制是肾小球毛细血管壁通透性障碍，但其确切机制尚不清楚。近期肾小球毛细血管壁的高通透性是由于肾小球上皮细胞和肾小球基底膜的紊乱所致。众所周知，在蛋白尿状态下，上皮细胞与基底膜分离。这可能是由于上皮细胞和基底膜之间的附着发生了某种程度的紊乱。近年来有报道称，整合素家族在维持上皮细胞和基底膜的附着方面起着重要作用。在本报告中，我们描述了整合素在肾小球中的表达量和状态。大鼠诱导PAN肾病和被动Heymann肾病，分别在第3天和第7天、第4天和第7天对PAN肾病和Heymann肾病肾切片进行免疫荧光检测。用激光共聚焦显微镜观察切片，并用计算机图像分析仪分析数据。在PAN肾病第3天，整合素的表达量增加，而在正常大鼠肾脏中，线性样表达量减少。在第7天，线性模式恢复。在第4天的Heymann肾病切片上，其表达量减少，第7天上皮细胞可见腺样样。这些结果强烈提示整合素在肾小球毛细血管壁的表达模式比其数量更为重要。

Proteiuria is a hallmark of glomerulonephritis, and induces progressive renal insufficiency. It is believed that the mechanism of urinary protein excretion is the disorder of permeability of glomerular capillary wall, but its precise mechanism is still unclear. Recently hyperpermeability of glomerular capillary wall is due to the disorder of glomerular epithelial cell and glomerular basement membrane. It is widely known that the epithelial cells detach from basement membrane in proteiuric state. This may be due to somehow derangement of attachment between epithelial cells and basement membrane. Recently it is reported that integrin family plays an important role for keeping attachment of epithelial cell and basement membrane. In this report we describe the amount and status of integrin expression in glomeruli.PAN nephrosis and passive Heymann nephrosis were induced in rats and immunofluorescence was carried out on the kidney sections from PAN nephrosis at day 3 and 7, from Heymann nephrosis at day 4 and 7. The sections were observed by confocal laser microscopy and data were analyzed computerized image analyzer. The amount of integrin expression has increased at day 3 of PAN nephrosis, but the linear like expression diminished which is observed on normal rat kidney. At day 7 the linear like pattern recovered. On the section of Heymann nephrosis at day 4, the amount of its expression decreased and day 7 the glanular pattern was observed in the epithelial cells. These results strongly indicated the pattern of integrin expression at glomerular capillary walls is more important than its amount.