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目的 :通过对扬子鳄胚胎后肾组织发生过程的观察 ,探讨其后肾发生及分化的规律和特点。材料与方法 :用组织学及细胞化学染色法 ,在光镜下对 9个不同发育时期的胚胎进行了观察。结果 :孵育第 18天 ,从泄殖腔附近发出的输尿管芽向生后肾组织侵入生长 ,生后肾组织产生许多生后肾小泡。第 2 4天出现集合管及肾小管、肾小囊的雏形。第 30天肾小管显著伸长并发生折叠 ,出现近曲小管、远曲小管和肾小管中间段的形态分化。第 4 0～ 62天 ,肾小体逐渐发育成熟 ,肾小管各段逐步出现机能分化。在后肾发育过程中 ,PAS阳笥物质首先出现于集合管上皮细胞 ,其次是远曲小管 ,最后是肾小管中间段和近曲小管。第 2 4～ 30天中 ,集合管、肾小管及肾小囊上皮细胞中 RNA含量均丰富 ,呈弥散型分布 ,第 4 0天以后肾组织中 RNA含量迅速减少。结论 :扬子鳄后肾不同区域肾单位的发生与分化存在明显的时间差异。肾单位的分化中 ,集合管与远曲小管分化较早 ,肾小管中间段及近曲小管分化较迟
OBJECTIVE: To observe the occurrence and differentiation of renal allografts in Alligator sinensis embryos by observing the process of posterior kidney tissue. MATERIALS AND METHODS: Nine embryos of different developmental stages were observed under light microscope by histology and cytochemical staining. Results: On the 18th day of incubation, the ureteral buds emerging from the vicinity of the cloaca developed invaded growth to the posterior kidney tissue. After birth, the kidney tissue produced many postnatal kidney vesicles. On the 24th day, the rudiments of collecting tube, renal tubule and renal capsule appeared. On the 30th day, the renal tubules were significantly elongated and folded, showing the morphological differentiation of proximal tubule, distal tubule and middle tubule. From the 40th to the 62nd day, the renal bodies gradually developed and matured, and the tubular segments gradually developed functional differentiation. In the process of development of the kidneys, PAS sulcus material first appeared in the collecting duct epithelial cells, followed by distal convoluted tubules, and finally in the middle of the renal tubules and proximal convoluted tubules. From the 24th to the 30th day, the contents of RNA in collecting duct, tubule and cystic epithelial cells were rich and diffusely distributed, and the content of RNA in renal tissues rapidly decreased after the 40th day. Conclusion: The occurrence and differentiation of nephrons in different areas of posterior kidney of Chinese alligator have obvious time difference. Differentiation of the nephrons, collection tube and distal convoluted tubule earlier, the middle of the tubular and proximal tubule later