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.