Ideura T, Solez K, Heptinstall R H
Am J Pathol. 1980 Jan;98(1):123-50.
Acute renal failure was produced in vasopression-pretreated rabbits by clamping the left renal pedicle for one hour and removing the opposite kidney. Treatment with clonidine, as antihypertensive drug that blunts the kidney's response to vasopressin, resulted in significantly higher creatinine clearance and urine flow rate in the first 6 hours after unclamping. Clonidine (30 microgram/kg given intravenously 30 minutes before unclamping) also significantly lessened the number of hyaline casts in outer medullary tubules and inner medullary loops of Henle 6 hours after unclamping and reduced the number of abnormal tubular contours in microadiograms produced by infusing barium sulfate into the renal artery at sufficient pressure to rupture glomerular capillaries, causing an escape of contrast material into the tubules. The spaces consistently observed between the ends of barium columns and hyaline casts in microdissection studies and the great lengths of the hyaline casts suggest that hyaline casts obstruct the flow of tubular fluid. Clonidine treatment resulted in fewer, shorter, and thinner hyaline casts. These results indicate that tubular obstruction by hyaline casts plays an important role in early postischemic acute renal failure, and that clonidine's beneficial effect is due in part to a reduction in cast formation.
通过夹闭左肾蒂一小时并切除对侧肾脏，在接受血管加压素预处理的家兔中制造急性肾衰竭。可乐定作为一种能减弱肾脏对血管加压素反应的抗高血压药物，在解除夹闭后的最初6小时内，其治疗使肌酐清除率和尿流率显著升高。可乐定（在解除夹闭前30分钟静脉注射30微克/千克）在解除夹闭6小时后，也显著减少了外髓质肾小管和髓袢升支粗段内透明管型的数量，并减少了在以足够压力向肾动脉注入硫酸钡以致使肾小球毛细血管破裂，造影剂逸入肾小管所产生的微血管造影中异常肾小管轮廓的数量。在显微解剖研究中，在钡柱末端和透明管型之间始终观察到的间隙以及透明管型的巨大长度表明，透明管型阻碍了肾小管液的流动。可乐定治疗使透明管型数量减少、长度变短且变细。这些结果表明，透明管型所致的肾小管梗阻在缺血后早期急性肾衰竭中起重要作用，并且可乐定的有益作用部分归因于管型形成的减少。
