In Vivo Fluorescence Microscopy of Microcirculation in the Renal Cortex of Mice

Abstract

In vivo fluorescence microscopy was used for experimental studies of the renal cortical microcirculation in mice. The effects of i.v. infusions of mannitol and iohexol were studied in untreated mice as well as in mice after temporary renal ischemia. All infusions produced marked effects on the distribution and velocity of cortical blood flow with no differences between iohexol and mannitol. The renal cortical blood flow was inhomogeneous with respect to different capillaries and there was an initial rise in the number of capillaries with increased blood flow after infusions of both mannitol and iohexol. There was an initial increase in the number of capillaries with a decreased blood flow following 30 min of ischemia. This increase was reduced by both types of infusions, suggesting a beneficial effect on renal cortical blood flow. Neither mannitol nor contrast medium exhibited any adverse effects in ischemic kidneys that would be likely to affect renal function. However, 5 min after the infusions there was an increasing number of capillaries with decreased blood flow in all groups.