The effects of nephrectomy on the developing fetus

Bilateral renal pathologies such as renal agenesis and renal dysplasia and lower urinary tract obstruction have been reported to result in pulmonary hypoplasia. Although oligohydramnios and resultant thoracic compression was suggested to be the cause of pulmonary hypoplasia, the exact mechanism is still unknown. Additionally the effect of absence of renal tissue on the development of the fetus has not been previously studied in detail. Therefore an experimental study was planned to investigate the effects of fetal nephrectomy on development. The fetuses from 27 New Zealand white rabbits were studied on the 23rd day of gestation. Right ovarian-end fetuses underwent bilateral nephrectomy or sham operations. Rabbits underwent hysterectomy on gestational day 30, and live fetuses were studied. Fetal body, lung, heart and liver weights, and lung, heart and thorax volumes were determined, organ weight/body weight ratios were calculated. Additionally, lungs were evaluated by histological examination. Although fetal nephrectomy resulted in decreased body weight (BW), lung, heart, liver weights and heart weight/BW ratio (p < 0.05), lung weight/BW and liver weight/BW ratios did not differ. Additionally, heart and thorax volumes were significantly decreased in the nephrectomy group (p < 0.05). However lung volume and thorax volume/BW ratio did not differ between groups. The histological evaluation of lungs revealed exfoliated cells but normal lung development. Bilateral fetal nephrectomy results in small-for-gestational age (SGA) status during birth without affecting the development of organic systems. Since SGA status may be associated with decreased placentofetal blood flow, bilateral nephrectomy may act through decreasing placentofetal blood flow and/or through the lack of kidney-related growth factors.