Toubeau G, Nonclercq D, Zanen J, Laurent G, Schaudies P R, Heuson-Stiennon J A
Laboratory of Histology and Experimental Cytology, Faculty of Medicine, Mons-Hainaut University, Belgium.
Exp Nephrol. 1994 Jul-Aug;2(4):229-39.
Rat kidneys undergoing tubular regeneration after ischaemic injury have been examined with regard to EGF, EGF receptor and vimentin, using immunohistochemical techniques. Renal ischaemia was induced in male Sprague-Dawley rats by 35-min clamping of renal arteries. Groups (n = 4-6) of experimental animals were killed at different time intervals (12, 24, 48, 72 h, 7 and 14 days) after reperfusion. One hour before sacrifice, each rat received i.p. 200 mg/kg 5-bromo-2'-deoxyuridine (BrdU) for the immunocytological demonstration of DNA synthesis. Renal necropsies were processed to reveal by immunohistochemistry EGF, EGF receptor, vimentin, and BrdU incorporated into DNA of S-phase cells. Tubular necrosis particularly involved proximal straight tubules in the outer stripe of the outer medulla and was followed by tubular regeneration, with a peak of cell proliferation at 48-72 h and an apparent dedifferentiation of tubular epithelium. As soon as 12 h after ischaemia, there was a substantial reduction of EGF immunostaining and the incidence of distal tubules showing EGF immunoreactivity reached a nadir at 48 h. In control kidneys, EGF receptor was mostly immunolocalized in proximal tubules although juxtaglomerular cells also exhibited immunolabelling. EGF receptor immunostaining in tubular epithelium showed no major change during the episode of tubular necrosis (12-24 h) but disappeared in tubular profiles undergoing regenerative hyperplasia (48-72 h). No vimentin immunostaining was found in tubules of control kidneys. Tubular epithelium remained mostly vimentin negative during the early phase of tubular necrosis/regeneration (12-72 h). By contrast, 7 days after ischaemia numerous dedifferentiated tubules expressed vimentin. In conclusion, tubular regeneration after ischaemia is associated with a typical sequence of transient events: (1) reduction of EGF immunostaining; (2) disappearance of EGF receptors during the mitogenic response; (3) expression of vimentin in tubular epithelium, and (4) return to a normal appearance.
利用免疫组织化学技术，对缺血性损伤后正在经历肾小管再生的大鼠肾脏进行了关于表皮生长因子（EGF）、EGF受体和波形蛋白的研究。通过夹闭雄性Sprague-Dawley大鼠肾动脉35分钟诱导肾缺血。在再灌注后的不同时间间隔（12、24、48、72小时、7天和14天）处死实验组动物（每组n = 4 - 6）。在处死前1小时，每只大鼠腹腔注射200mg/kg 5-溴-2'-脱氧尿苷（BrdU），用于免疫细胞化学法显示DNA合成。对肾脏进行尸检，通过免疫组织化学方法揭示EGF、EGF受体、波形蛋白以及掺入S期细胞DNA中的BrdU。肾小管坏死尤其累及外髓质外带的近端直小管，随后是肾小管再生，细胞增殖高峰出现在48 - 72小时，肾小管上皮出现明显的去分化。缺血后12小时，EGF免疫染色就大幅减少，显示EGF免疫反应性的远端小管发生率在48小时达到最低点。在对照肾脏中，EGF受体大多免疫定位在近端小管，尽管球旁细胞也显示免疫标记。肾小管上皮中的EGF受体免疫染色在肾小管坏死期（12 - 24小时）无明显变化，但在经历再生性增生的肾小管轮廓中消失（48 - 72小时）。在对照肾脏的小管中未发现波形蛋白免疫染色。在肾小管坏死/再生的早期阶段（12 - 72小时），肾小管上皮大多仍为波形蛋白阴性。相比之下，缺血7天后，许多去分化的小管表达波形蛋白。总之，缺血后肾小管再生与一系列典型的短暂事件相关：（1）EGF免疫染色减少；（2）在有丝分裂反应期间EGF受体消失；（3）波形蛋白在肾小管上皮中的表达；（4）恢复正常外观。
