Shea S M, Morrison A B
J Cell Biol. 1975 Nov;67(2PT.1):436-43. doi: 10.1083/jcb.67.2.436.
Kidney from normal male albino rats, of body weight 170-200 g, was fixed by arterial perfusion with buffered tannic acid-glutaraldehyde, and postfixed with osmium tetroxide. Random and isotropic ultrathin sections from 23 different glomeruli from five rats were mounted on slot grids for staining and electron microscopy. Prints of whole glomeruli at a magnification of 3,909 were analyzed by stereological methods. The mean glomerular volume was (8.048 +/- 0.474) X 10(5) mum3 if the glomeruli are treated as spheres. The area of the basement membrane was 0.281 +/- 0.017 mm2 per glomerulus, of which 0.184 +/- 0.011 mm2 represents peripheral basement membrane. The aggregate epithelial slit length per glomerulus was 65.19 +/- 3.84 cm, of which 48.69 +/- 2.87 cm represents epithelial slits abutting on the peripheral basement membrane. Assuming that a slit diaphragm is 390 A wide, and that the pores of the slit diaphragm represent 26% of its area, the mean pore area is 3.96 cm2, of which 2.96 cm2 represents the area of peripheral pores. These findings are discussed in the context of the hydrodynamic theory of glomerular ultrafiltration. We conclude that the porous substructure of the glomerular slit diaphragm is significant in determining the hydraulic conductivity of the glomerulus and hence also solute flux during ultrafiltration.
选用体重170 - 200克的正常雄性白化大鼠的肾脏，通过动脉灌注缓冲单宁酸 - 戊二醛进行固定，然后用四氧化锇进行后固定。从五只大鼠的23个不同肾小球中随机选取各向同性的超薄切片，安装在槽形网格上用于染色和电子显微镜观察。通过体视学方法分析放大3909倍的整个肾小球的照片。如果将肾小球视为球体，其平均肾小球体积为(8.048±0.474)×10(5)立方微米。每个肾小球基底膜的面积为0.281±0.017平方毫米，其中0.184±0.011平方毫米为外周基底膜。每个肾小球上皮裂隙的总长度为65.19±3.84厘米，其中48.69±2.87厘米为邻接外周基底膜的上皮裂隙。假设裂孔隔膜宽390埃，且裂孔隔膜的孔隙占其面积的26%，则平均孔隙面积为3.96平方厘米，其中2.96平方厘米为外周孔隙面积。在肾小球超滤的流体动力学理论背景下讨论了这些发现。我们得出结论，肾小球裂孔隔膜的多孔亚结构在决定肾小球的水力传导率以及因此在超滤过程中的溶质通量方面具有重要意义。
