Plastic foil technique attenuates inflammation in mesenteric intravital microscopy

Background Interpretation of intravital microscopic observations is complic ated by the "inflammatory"-type response to the trauma inflicted on the tis sue by the surgical preparation. The present study evaluates different expe rimental conditions for prolonged observations of the mesenteric microcircu lation in the rat. Methods. The mesentery was exteriorized through a median laparotomy and sub jected to an organ bath or a modified plastic foil technique. Hemodynamic, metabolic, respiratory, and microcirculatory data were analyzed. Results. In contrast to the plastic foil technique, which yielded stable ba seline values over a 5-h observation period, venular velocity and wall shea r rates decreased significantly in the organ bath technique, and leukocyte adhesion to the endothelium was significantly increased. Likewise, abdomina l blood how decreased significantly by 35% and base excess declined (-10.0 +/- 0.4 mmol/L) in the organ bath, with reduced pCO(2) (26.4 +/- 2.5 mm Hg vs 33.7 +/- 1.1 mm Hg in plastic foil technique) due to respiratory pH comp ensation. Conclusions. The plastic foil technique was found clearly superior to the o rgan bath technique for maintenance of stable baseline metabolic, hemodynam ic, and microcirculatory conditions in mesenteric intravital microscopy. (C ) 2000 Academic Press.