Bogaert G A, Gluckman G R, Mevorach R A, Kogan B A
Department of Urology, University of California School of Medicine, San Francisco 94143-0738, USA.
J Urol. 1995 Aug;154(2 Pt 2):694-9. doi: 10.1097/00005392-199508000-00094.
To determine whether the increase in renal blood flow and preservation of renal function that we demonstrated after 10 days of chronic partial bladder obstruction in the third trimester fetal lamb also occur after earlier longer obstruction, we modified our preparation and studied the effects of 35 days of obstruction begun during the second trimester. Partial bladder obstruction was created in 10 fetal lambs at 90 days of gestation (term equals 147 days). At repeat surgical intervention 28 days later vascular catheters and a left renal artery flow transducer were placed, and catheters were externalized. We then studied renal blood flow and function at gestational ages 120 days and 125 days after 30 days and 35 days of obstruction, respectively. Tissue was obtained for histology at the time of sacrifice. Eight control fetal lambs without obstruction were studied in a similar way. Bilateral hydroureteronephrosis was noted in all fetal lambs after partial obstruction, whereas the kidneys and bladders of the control animals had a normal appearance. Renal blood flow was higher in the obstructed fetal lambs than in controls (20.2 +/- 4.9 versus 10.2 +/- 0.9 ml. per minute per kg., p < 0.05 after 30 days and 17.1 +/- 2.7 versus 9.7 +/- 0.9 per minute per kg., p < 0.05 after 35 days). There was no evidence of decreased renal function by any parameter and, in fact, glomerular filtration rate and urine volume were increased after 30 days of obstruction (1.59 +/- 0.32 versus 0.69 +/- 0.07 ml. per minute per kg., p < 0.05 and 15.7 +/- 4.3 versus 5.2 +/- 0.8 ml. per hour per kg., p < 0.05, respectively). Histological studies demonstrated normal architecture of the kidneys but thinned cortex. We conclude that the physiological responses of the fetus are such that partial lower urinary tract obstruction in our preparation results in a prolonged increase in renal blood flow and preservation of renal function.
为了确定在孕晚期胎羊慢性部分膀胱梗阻10天后我们所证实的肾血流量增加和肾功能保留在更早的更长时间梗阻后是否也会出现，我们改进了实验准备并研究了在孕中期开始的35天梗阻的影响。在妊娠90天（足月为147天）时对10只胎羊造成部分膀胱梗阻。28天后再次进行手术干预时，放置血管导管和左肾动脉血流换能器，并将导管引出体外。然后我们分别在梗阻30天和35天后的孕龄120天和125天时研究肾血流量和功能。处死时获取组织进行组织学检查。以类似方式研究了8只未梗阻的对照胎羊。部分梗阻后所有胎羊均出现双侧输尿管肾盂积水，而对照动物的肾脏和膀胱外观正常。梗阻胎羊的肾血流量高于对照组（30天后分别为20.2±4.9与10.2±0.9毫升每分钟每千克，p<0.05；35天后为17.1±2.7与9.7±0.9每分钟每千克，p<0.05）。没有任何参数表明肾功能下降，事实上，梗阻30天后肾小球滤过率和尿量增加（分别为1.59±0.32与0.69±0.07毫升每分钟每千克，p<0.05；15.7±4.3与5.2±0.8毫升每小时每千克，p<0.05）。组织学研究显示肾脏结构正常但皮质变薄。我们得出结论，胎儿的生理反应使得我们实验准备中的部分下尿路梗阻导致肾血流量长期增加和肾功能保留。
