| Popis: |
Background and Objectives: In this study, the spatial courses of the connecting tubule (CNT) of nephron from different depth of cortex and the collecting duct (CD) in mouse kidney was established with the aid of three-dimensional visualization technology. Subjects and Methods: Kidneys from three C57/BL/6J mice were removed after perfusion fixation. The tissue blocks were cut perpendicular to the longitudinal axis of the kidney and embedded in Epon-812. A total of 2000, 2.5-μm-thick consecutive sections were obtained from the renal capsule to papilla. After acquiring the digitalized images and alignment, the CNT from 137 nephrons were traced with the custom-made programs. The spatial arrangement of the CNT was visualized, and the length was measured. Results: Each CD received CNT from 5 to 7 nephrons. The CNT from different level of cortex all drained into the CD at superficial cortex but took different path. The CNT from superficial cortical nephron joined CD directly, while the CNT from middle and juxtamedullary cortical nephron joined each other to form an arcade, and the latter drained into CD at superficial cortex. The length of the arcade ranged 400–800 μm. Conclusions: The CNT joined CD at superficial cortex, which means the fluid along the CD from the cortex would not be added from outside, contributing to stabilization of the hormone regulation in the transportation of solutes and water along the CD from cortex to medulla. |
