Marcel de Vries P A, Navis G, de Boer E, de Jong P E, de Zeeuw D
Groningen Institute for Drug studies (GIDS), Department of Internal Medicine, State University Hospital, The Netherlands.
Kidney Int. 1997 Jul;52(1):244-7. doi: 10.1038/ki.1997.327.
Renal function measurement by clearance methods relies on accurately timed urine collection. In small experimental animals, renal function measurement is usually performed under anesthesia and/or with the application of bladder catheters to ensure accurate urine collection. To avoid both anesthesia and the need for bladder catheters we developed a method to measure glomerular filtration rate (GFR) in spontaneously voiding conscious rats. GFR was measured as the urinary clearance of constantly infused 125I-iothalamate. To correct for incomplete bladder emptying urinary clearance of 125I-iothalamate was multiplied by the ratio of plasma and urinary clearance of simultaneously infused 131I-hippuran, a correction method that has been previously validated in humans. Reproducibility of the technique was evaluated by analysis of the results of four consecutive clearance periods during the day (intra-assay variation) in a group of 17 rats and of two consecutive clearance periods on two or three separate days in a group of 20 rats (inter-assay variation), all with normal renal function. Application of the correction method reduced the intra-assay coefficient of variation (mean +/- SD) from 37.4 +/- 14.3 to 5.4 +/- 2.3% (P < 0.05). The mean inter-assay coefficient of variation fell slightly from 23.4 +/- 10.3 to 11.0 +/- 7.2% (P < 0.10). In rats with moderately impaired renal function (N = 8) the intra-assay variation fell from 27.9 +/- 20.7 to 2.7 +/- 1.6% (P < 0.05). Our data show that this correction method is a useful technique to assess renal function in conscious, spontaneously voiding rats.
通过清除率方法测量肾功能依赖于准确计时的尿液收集。在小型实验动物中，肾功能测量通常在麻醉状态下和/或使用膀胱导管来确保准确的尿液收集。为了避免麻醉和使用膀胱导管的需求，我们开发了一种在自然排尿的清醒大鼠中测量肾小球滤过率（GFR）的方法。GFR通过持续输注的125I - 碘肽酸盐的尿清除率来测量。为校正膀胱排空不完全的情况，125I - 碘肽酸盐的尿清除率乘以同时输注的131I - 马尿酸的血浆清除率与尿清除率的比值，这种校正方法先前已在人类中得到验证。通过分析一组17只大鼠在一天内四个连续清除期的结果（批内变异）以及一组20只大鼠在两到三个不同日子的两个连续清除期的结果（批间变异）来评估该技术的可重复性，所有大鼠肾功能均正常。应用校正方法使批内变异系数（平均值±标准差）从37.4±14.3降至5.4±2.3%（P<0.05）。批间变异系数平均值从23.4±10.3略降至11.0±7.2%（P<0.10）。在肾功能中度受损的大鼠（N = 8）中，批内变异从27.9±20.7降至2.7±1.6%（P<0.05）。我们的数据表明，这种校正方法是评估清醒、自然排尿大鼠肾功能的一种有用技术。
