Prenatal evaluation of kidney function in mice using dynamic contrast-enhanced magnetic resonance imaging

Glomerular differentiation starts as soon as embryonic stage 12 in mice and suggests that kidneys may be functional at this stage. Dynamic contrast-enhanced magnetic resonance microscopy, a noninvasive imaging technique, was used to assess renal function establishment in utero. Indeed, in adults (n=3), an intravenous injection of gadolinium-DOTA induced in a first step a massive and rapid drop in kidney signal intensity followed, in a second step, by a drop in bladder signal intensity. The delay in signal changes between kidney and bladder reflected glomerular filtration. Pregnant mice underwent anatomical and dynamic contrast-enhanced magnetic resonance microscopy on postcoital days 12–13 (n=2), 13–14 (n=1), 14–15 (n=3), 15–16 (n=2), 16–17 (n=3), 17–18 (n=3), and 18–19 (n=1). Kidneys and bladder were unambiguously depicted prior to contrast agent injection on stage 15–16 embryos. Contrast agent injection allowed kidney, detection as early as stage 12–13 but not bladder. Kinetics of signal changes demonstrated that glomerular filtration is established at embryonic stage 15–16 in mice. Thus, anatomical and dynamic contrast-enhanced magnetic resonance microscopy may be a powerful noninvasive method for in vivo prenatal developmental and functional studies.