Tanner G A, Evan A P
Department of Physiology and Biophysics, Indiana University School of Medicine, Indianapolis.
Kidney Int. 1989 Dec;36(6):1050-60. doi: 10.1038/ki.1989.300.
This study examined the effect of blocking proximal tubule lumens on glomerular and early proximal tubular morphology. Single nephrons in the rat kidney were blocked with wax by micropuncture. After one day, one week, or one month of obstruction, the kidneys were fixed with glutaraldehyde by intravascular perfusion, and nephron structure was examined by light and electron microscopy. Following obstruction, glomerular changes developed more slowly than tubular changes. After one day, the only change noted in some glomeruli was the presence of inflammatory cells. The only tubule change upstream to the block was a focal loss of apical microvilli. This is in contrast to the severe damage previously reported (Evan, Tanner: Kidney Int 30: 818-827, 1986) in downstream proximal tubule segments at this time. After one month of obstruction, glomerular size was decreased and the glomerular filtration membrane was abnormal. Tubular cell size was decreased, apical microvilli were lost, basolateral interdigitations were reduced, and mitochondria were fewer and abnormally oriented. Interstitial fibrosis was present. Changes in nephron structure develop slowly after obstruction, perhaps because continued filtration and reabsorption maintain nephron integrity. Eventually, blocked nephrons atrophy, probably because of reduced blood flow, disuse, and inflammatory responses.
本研究探讨了阻塞近端肾小管管腔对肾小球及早期近端肾小管形态的影响。通过微穿刺用蜡阻塞大鼠肾脏中的单个肾单位。在阻塞1天、1周或1个月后，通过血管内灌注用戊二醛固定肾脏，并通过光学显微镜和电子显微镜检查肾单位结构。阻塞后，肾小球的变化比肾小管的变化发展得更缓慢。1天后，在一些肾小球中观察到的唯一变化是存在炎性细胞。阻塞部位上游的肾小管唯一变化是顶端微绒毛的局灶性缺失。这与此前报道的（埃文、坦纳：《肾脏国际》30: 818 - 827, 1986）此时下游近端肾小管节段的严重损伤形成对比。阻塞1个月后，肾小球大小减小，肾小球滤过膜异常。肾小管细胞大小减小，顶端微绒毛缺失，基底外侧指状突减少，线粒体数量减少且方向异常。存在间质纤维化。阻塞后肾单位结构的变化发展缓慢，可能是因为持续的滤过和重吸收维持了肾单位的完整性。最终，阻塞的肾单位萎缩，可能是由于血流减少、废用和炎症反应。
