Chronic intrauterine exposure to endotoxin does not alter fetal nephron number or glomerular size

A reduced nephron endowment early in life adversely impacts on long-term functional reserve in the kidney. A recent study has shown that acute exposure to chorioamnionitis during late gestation can adversely impact on nephrogenesis. The present study aimed to examine the effects of chronic, low-dose endotoxin exposure in utero, during the period of nephrogenesis, on nephron number and glomerular size in preterm lambs. Ewes were administered either: endotoxin (lipopolysaccharide, LPS; 1mg/day) or saline at 110 to 133 days of gestation (term 147 days) via surgically implanted osmotic mini-pumps within the amniotic cavity. The ewes were induced to deliver preterm at 133 days gestation and the kidneys of the lambs were analysed at 8 weeks post term-equivalent age. Nephron number per kidney was determined using an unbiased optical disector/fractionator stereological approach; renal corpuscle size was also stereologically measured. At 8 weeks after term-equivalent age there was no significant effect of in utero exposure of endotoxin on body weight or kidney weight and there were no significant differences in nephron number, nephron density, or renal corpuscle volume between groups. We conclude that chronic intrauterine inflammation during the period of nephrogenesis may not adversely impact on the number of nephrons formed within the kidney or on the volume of the renal corpuscle. This article is protected by copyright. All rights reserved.