Increased hindlimb leukocyte concentration in a chronic rodent model of venous hypertension

Background The pathophysiologic mechanism for tissue damage in chronic veno us insufficiency (CVI) is venous hypertension (VH), the primary mediator be hind leukocyte trapping in tissues. We developed a new rodent model of chro nic hindlimb VH to allow testing of the microvascular dysfunction that occu rs in clinical CVI. Materials and methods. Hindlimb VH was created in adult rats (similar to 35 0 g, male, Wistar) by ligation of the inferior vena cave, bilateral common iliac veins, and bilateral common femoral veins. In a sham group, a loose t ie was placed around the same vessels. One week later, pressure catheters w ere placed in the right common carotid artery, right internal jugular vein (forelimb), and right superficial epigastric vein (hindlimb). Measurements were taken 15 min later, to allow for stabilization. Bilateral forelimb and hindlimb skin specimens were harvested. The myeloperoxidase (MPO) assay, a n indicator of tissue leukocyte trapping, was performed using a well-descri bed, standard technique. Results. In the chronic rats (n = 8), the hindlimb pressures (12.6 +/- 3.2 mm Hg) were significantly elevated (P < 0.05) when compared to forelimb pre ssures (1.75 +/- 0.71) and to chronic sham rat (n = 6) hindlimb (3.3 +/- 1. 2) pressures. There was a significant (P < 0.05) elevation of MPO activity in hindlimbs of the chronic group (32.9 +/- 13.9 units) when compared to fo relimbs (17 +/- 11.3) and sham hindlimbs (18 +/- 10.2). Conclusions. In our chronic model, as in clinical studies and previous acut e investigations, we have demonstrated, using an MPO assay, an increase in the amount of cutaneous leukocytes in the hindlimbs with chronic VB but not in experimental forelimbs or sham hindlimbs or forelimbs. (C) 1999 Academi c Press.