Ishii K, Sugimoto T, Kamikawa S, Kanazawa T, Nakatani T, Yamamoto K, Kishimoto T, Funae Y
Department of Urology, Osaka City University Medical School.
Hinyokika Kiyo. 1998 Apr;44(4):245-51.
To elucidate the intrarenal distribution of oxalate and to reveal the first site of calcium oxalate crystal fixation along the nephron, we carried out 14C-oxalate renal microautoradiography by the thaw mount method 30, 60 and 90 min after intravenous administration of 14C-oxalate, in normal rats and in hyperoxaluric rats fed a vitamin B6-deficient diet for 4 and 9 weeks. In normal rats, radioactivity was observed in the entire kidney area at 30 min after the injection and at 90 min there was radioactivity only in the papilla, where radioactivity appeared in the parenchyma, mamely the epithelial cells of collecting ducts and the surrounding interstitial tissue. In hyperoxaluric rats, microautoradiograms showed the spotted deposits of 14C-oxalate in both renal papilla and medulla. In 600 x magnification of the autoradiograms, most of the deposits were detected in the epithelial cells of collecting ducts and the surrounding interstitial tissue. These deposits were identified by a polarizing microscope and X-ray microanalysis as crystal deposits of calcium oxalate. These results indicated that oxalate remained for an extended period of time in the epithelial cells of collecting ducts and in the surrounding interstitial tissue in renal papilla, and the calcium oxalate crystals fixed to the same tissue was the first step in the development of calcium oxalate stones.
为了阐明草酸盐在肾脏内的分布，并揭示草酸钙晶体沿肾单位固定的首个部位，我们通过冻融法对正常大鼠以及喂食缺乏维生素B6饮食4周和9周的高草酸尿大鼠在静脉注射14C-草酸盐后30、60和90分钟进行了14C-草酸盐肾脏显微放射自显影。在正常大鼠中，注射后30分钟时在整个肾脏区域观察到放射性，而在90分钟时仅在肾乳头处有放射性，放射性出现在实质中，即集合管的上皮细胞和周围的间质组织中。在高草酸尿大鼠中，显微放射自显影片显示14C-草酸盐在肾乳头和髓质中均有斑点状沉积。在自显影片600倍放大时，大部分沉积物在集合管的上皮细胞和周围的间质组织中被检测到。通过偏光显微镜和X射线微分析将这些沉积物鉴定为草酸钙晶体沉积物。这些结果表明，草酸盐在肾乳头集合管的上皮细胞和周围的间质组织中长时间留存，并且固定在同一组织中的草酸钙晶体是草酸钙结石形成的第一步。
