Leukocytes extravasation in acute homocysteinemic rats

Homocysteine may promote atherogenesis and thrombogenesis by enhancing leukocyte–endothelium interactions. We explored this hypothesis in an acute hyperhomocysteinemia rat model, which was created by a continuous venous homocysteine infusion (4 ml/h/kg body weight) with 2.5 and 10 mg/ml d, l-homocysteine upto 90 min. Venous homocysteine levels were monitored periodically and varied 65–276 μmol/l, a range observed frequently in homocysteinemic and homocystinuric patients. We measured hemodynamic parameters in mesentery by intravital microscopy in rats infused with homocysteine ( N=5 for each dose) and saline ( N=7). Homocysteine infusion for 90 min did not change the mean carotid arterial blood pressure, velocity of red blood cells and rolling leukocyte flux. However at the dose of 10 mg/ml the venular wall shear rate was reduced to 66–69% of the pre-infusion value ( P