Dextran vs. hydroxyethylstarch in inhibition of postischemic leukocyte adherence in striated muscle

Microvascular injury associated with ischemia/reperfusion (I/R) is characterized by both "no reflow" and "reflow paradox." Prophylactic isovolemic hemodilution with dextran 60 to a hematocrit of 30% has been shown to prevent I/R-induced capillary no reflow in striated muscle. The objective of the present study was to analyze whether hemodilution prior to ischemia has the potential to reduce postischemic leukocyte-endothelium interaction, which is known to be one of the major components of I/R-induced reflow paradox. Syrian golden hamsters (n = 21) were fitted with a dorsal skinfold chamber, which contains striated muscle and subcutaneous tissue and allows for repetitive analyses of the microcirculation by means of intravital fluorescence microscopy. Four hr of pressure-induced ischemia and 30 min of subsequent reperfusion (controls, n = 7) resulted in a significant (P < 0.05) increase of microvascular leukocyte accumulation (40,630 +/- 12,731 mm-3) and adherence to the endothelial lining of postcapillary venules (74.2% +/- 11.5%) when compared to preischemic baseline (7,502 +/- 1,700 mm-3 and 3.4% +/- 1.0%, respectively). Recovery was not complete after an observation period of 24 hr reperfusion [13,735 +/- 2,666 mm-3 (P < 0.05) and 18.5% +/- 6.0% (P < 0.05)]. Prophylactic isovolemic hemodilution with 6% dextran 60 (Dx60) to a hematocrit of 30% (Dx60, n = 7) significantly attenuated postischemic leukocyte accumulation (23,402 +/- 13,837 mm-3; P < 0.05 vs. controls) and adherence (22.6% +/- 6.4%; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)