小鼠肾血管球滤过膜发育的电镜研究

A STUDY BY TRANSMISSION ELECTRON MICROSCOPY OF THE DEVELOPING GLOMERULAR FILTRATION MEMBRANE IN MOUSE KIDNEY

目的研究发育中小鼠血管球滤过膜的变化。方法应用透射电镜观察胚胎和新生小鼠血管球滤过膜的超微结构。结果在肾小体的发育过程中,足细胞形状明显变薄,足突数量逐渐增多,其形状逐渐窄小,足突间裂孔和裂孔膜出现;足细胞下、内皮细胞下先后出现基膜,而后两种基膜融合形成一层较厚的基膜。随着毛细血管袢的不断增生,在足细胞下方出现新合成的环状或袋状的基膜片段;内皮细胞形状也明显变薄,出现大量内皮孔。结论在小鼠肾小体的发育过程中,足细胞和内皮细胞逐渐分化成熟,基膜最早来源于足细胞,随后内皮也参与合成基膜,发育晚期基膜的合成和更新主要由足细胞来完成。

Objective To study the ultrastructural changes of the developing glomerular filtration membrane in mice. Methods The glomerular filtration membrane of embryonic and postnatal mice was observed by transmission electron microscope. Results The analysis of filtration membrane components showed that during the development of the renal corpuscle, the height of maturing podocytes became remarkably reduced. The number of their foot processes steadily increased, and they became slimmer and filtration slit diaphragms began to appear between them. Subepithelial basement membrane appeared firstly, and then subendothelial basement membrane came in its wake, and the fusion of both led to the formation of a thick basement membrane. As the tuft of the capillary glomerulus grew, newly formed fragments of the basement membrane in the form of loops and outpockets started to be evident beneath epithelial podocytes. Endothelial cells became greatly flattened, and numerous fenestrae through the cells appeared. Conclusion During the development of the renal corpuscle, podocytes and endothelial cells differentiate to maturity gradually, podocytes are the earliest source of the basement membrane, then endothelial cells participate in its formation, from then on, the basement membrane is synthesized and renewed mostly by epithelial podocytes.