Williams R H, Thomas C E, Navar L G, Evan A P
Kidney Int. 1981 Apr;19(4):503-15. doi: 10.1038/ki.1981.48.
We studied ischemic acute renal failure in 28 dogs by micropuncture, microsphere, morphologic, and whole kidney hemodynamic techniques, 18 to 24 hours after the renal artery was clamped (clamping time, 60 to 90 min). Before the artery was clamped, renal blood flow (RBF) averaged 3.49 +/- (SEM) 0.23 ml/min x g and was not significantly different (3.70 +/- 0.34 ml/min x g) 18 hours after the ischemic episode. RBF autoregulatory capability was, however, significantly reduced. Fractional outer cortical blood flow decreased slightly from 41 +/- 2 to 36 +/- 3% (P less than 0.05) postischemia. Single nephron glomerular filtration rate (SNGFR) was highly variable from one animal to the next and ranged from 0 to 87 nl/min (mean, 36 +/- [SEM] 7 nl/min) in a manner similar to whole kidney inulin clearance, which ranged from 0 to 0.56 ml/min x g (mean, 0.30 +/- 0.05 ml+min x g). The correlation coefficient between SNGFR and inulin clearance was highly significant, indicating an association between SNGFR and whole kidney GFR. Proximal tubule pressure (PTP) averaged 20 +/- (SEM) 1 mm Hg. In 6 dogs, the glomerular filtration coefficient (Kf) was determined by measurements of stop-flow pressure, colloid osmotic pressure, SNGFR, PTP, and single nephron filtration fraction, Kf was below that obtained for control animals. Scanning electron microscopy (SEM) studies indicated that the endothelial fenestrations were reduced in number and size. These studies suggest that one major characteristic of ischemic nephropathy in the dog is a derangement in the filtration process. The maintenance of RBF in the postischemic phase may occur by utilization of the autoregulatory reserve of the renal vasculature.
我们通过微穿刺、微球、形态学和全肾血流动力学技术，对28只犬在肾动脉夹闭（夹闭时间60至90分钟）后18至24小时的缺血性急性肾衰竭进行了研究。在动脉夹闭前，肾血流量（RBF）平均为3.49±（标准误）0.23毫升/分钟×克，缺血发作后18小时无显著差异（3.70±0.34毫升/分钟×克）。然而，RBF的自身调节能力显著降低。缺血后，皮质外层血流分数从41±2%略微降至36±3%（P<0.05）。单肾单位肾小球滤过率（SNGFR）在不同动物之间差异很大，范围为0至87纳升/分钟（平均，36±[标准误]7纳升/分钟），其方式与全肾菊粉清除率相似，全肾菊粉清除率范围为0至0.56毫升/分钟×克（平均，0.30±0.05毫升/分钟×克）。SNGFR与菊粉清除率之间的相关系数非常显著，表明SNGFR与全肾肾小球滤过率（GFR）之间存在关联。近端小管压力（PTP）平均为20±（标准误）1毫米汞柱。在6只犬中，通过测量停流压力、胶体渗透压、SNGFR、PTP和单肾单位滤过分数来确定肾小球滤过系数（Kf），Kf低于对照动物。扫描电子显微镜（SEM）研究表明，内皮窗孔的数量和大小减少。这些研究表明，犬缺血性肾病的一个主要特征是滤过过程紊乱。缺血后阶段RBF的维持可能是通过利用肾血管系统的自身调节储备来实现的。
