目的  成年肾近端小管（PT）是急性肾小管病变最常累及同时也最易修复的节段，探讨基于三维可视化对发生发育期PT的形态发生进行时空性分析。   方法  取胚胎期（E）及生后（P）多时间点小鼠肾脏每组各3只，制备5 μm石蜡切片，Claudin-2免疫组织化学染色标记PT，体视学测量PT在肾皮质中体积密度；制备2.5 μm连续树脂切片并使之图像化，基于数字追踪和可视化软件展示PT的空间走行，同时测量其长度。   结果  P1小鼠PT在皮质中的体积密度明显大于胚胎期；随后经历了下降（P3、P5）、上升（P7）开始至稳定的成年水平（P28）；E14.5、E17.5和P5小管三维可视化显示，发生发育PT的长度、曲部的盘曲数随小管成熟逐渐增加，但低于成年PT；E14.5、E17.5 PT的基本空间走行与成年相似，而PT起始段的走行及PT直部在髓放线走行的毗邻关系则较成年差异较大；P5部分PT的走行接近成年PT。   结论  PT的发育，无论是皮质中的体积密度、长度、空间走行，与肾的整体发育一致，始于S小体期，贯穿于胚胎期并延续至生后，止于肾发育成熟（P28）。

Objective  Adult proximal tubule (PT) is not only the segment most frequently involved in acute renal tubule injury, but also the easiest to repair. It may be consistent with the rapid growth and differentiation mechanism of this segment during the development of the kidney, while the developing information is insufficient. Therefore, we three-dimensional visualized the developing PT to analysis its spatiotemporal morphogenesis.    Methods  The kidneys were obtained from mice at various developing time point, embryonic day (E), postnatal day (P). The volume density of Claudin-2 positive PT in the cortex was measured using a stereological method  in paraffin sections. After image recording and alignment of the serial sections, the spatial courses of the developing PT were traced and visualized in three dimensions using computer-assisted program. The length of the developing PT was calculated at the same time.    Results  The volume density of PT in the cortex of P1 mice was significantly higher than that in the embryonic stage. Then it experienced a decline (P3, P5), an increase (start at P7) to a stable adult level (P28). The tubular tracing showed that the lengths of developing PT and the number of convolutions of their convoluted part increased with the maturation, but lower than that of adultin E14.5, E17.5 and P5 PT in E14.5 and E17.5 mice were similar to that of adult with respect to general spatial courses. They were, however, significantly different from adult in the initial direction of PT and the arrangement of the straight part of PT in the medullary rays. While, it was in P5 that the spatial pattern of some PT was gradually approaching to the adult model.    Conclusion  This study demonstrated that the development of PT was consistent with the kidney development in terms of its volume density in cortex, length and spatial course. It started at the S-shaped body, kept throughout the embryonic period and continued to postnatal, ended at kidney maturation (P28).