Direct in vivo visualization of renal microcirculation by intravital CCD videomicroscopy

Several types of experimental techniques have been developed for the evaluation of renal microcirculation. Although each methodology possesses excellent and unique characteristics, it requires substantial artificial manipulation that might alter the renal microvascular responsiveness. To circumvent such limitation of previous ex vivo or in vitro approaches to glomerular microcirculation, we have developed a pencil lens-probe charge-coupled device (CCD) intravital videomicroscopic system which allows us to evaluate both systemic hemodynamics and renal microcirculation. Furthermore, real-time images of afferent and efferent arterioles as well as glomeruli can be continuously assessed, which would facilitate the functional characterization of these microvessels in vivo. Finally, the tapered nature of the CCD probe of this videomicroscopy may allow direct observation of the renal microvasculature in small animals (e.g., rats and mice). In conclusion, this novel technique is a valuable tool for unveiling the in vivo, in situ and intact renal microvascular behavior, and may provide further approaches to the understanding of renal microcirculation.