ABSTRACT
OBJECTIVES: To investigate leukocyte adherence in intestinal venules in experimental endotoxemia after treatment with the 21-aminosteroid U-74389G. DESIGN AND SETTING: Prospective, randomized, controlled animal study in an experimental laboratory. SUBJECTS: Twenty-one male Wistar rats weighing 190 +/- 40 g. INTERVENTIONS: The rats were divided equally into three groups: (a) control group, (b) endotoxemia (5 mg/kg lipopolysacharide from Escherichia coli O55:B5), and (c) endotoxemia and U-74389G administration 30 min before (3 mg/kg) and 60 min after endotoxin challenge (1.5 mg/ kg). MEASUREMENTS AND MAIN RESULTS: The distal small intestine of the animals was examined using intravital fluorescence videomicroscopy 2 h after endotoxin challenge. Leukocytes were stained in vivo by means of rhodamine 6G. In the endotoxemic animals we observed a fourfold increase in the count of firmly adherent leukocytes in submucosal post-capillary and collecting venules. Treatment with the 21-aminosteroid U-74389G significantly attenuated the count of sticking leukocytes in the collecting venules (control, 61 +/- 10 cells/mm2; lipopolysaccharide, 237 +/- 42 cells/mm2; U-74389G 125 +/- 9 cells/mm2; p < 0.05). In these venules leukocyte rolling behavior was comparable to that in the control group without endotoxin challenge. CONCLUSIONS: Administration of U-74389G, which has radical scavenging properties, attenuates leukocyte adherence in selected populations of intestinal venules which is found increased during endotoxemia. Thus, 21-aminosteroids may have an impact in the treatment of endotoxin-induced intestinal injury.
Subject(s)
Antioxidants/pharmacology , Cell Adhesion/drug effects , Leukocytes/drug effects , Mesenteric Veins/drug effects , Pregnatrienes/pharmacology , Toxemia/drug therapy , Animals , Endotoxins/toxicity , Free Radicals/metabolism , Hemodynamics/drug effects , Intestine, Small/blood supply , Intestine, Small/drug effects , Male , Mesenteric Veins/immunology , Microcirculation , Microscopy, Fluorescence , Microscopy, Video , Prospective Studies , Random Allocation , Rats , Rats, Wistar , Reactive Oxygen Species/metabolism , Toxemia/etiology , Toxemia/immunologyABSTRACT
OBJECTIVE: To determine the effect of the 21-aminosteroid U-74389G on tumor necrosis factor (TNF)-alpha release in experimental endotoxemia. DESIGN: Prospective, randomized, controlled animal study. SETTING: Experimental laboratory. SUBJECTS: Twenty-one male Wistar rats weighing 190+/-40 g. INTERVENTIONS: The rats were divided equally into 3 groups: a) control; b) endotoxemia (5 mg/kg lipopolysaccharide [LPS] from Escherichia coli 055:B5); and c) endotoxemia and U-74389G administration 30 mins before (3 mg/kg) and 60 mins after (1.5 mg/kg) endotoxin challenge. MEASUREMENTS AND MAIN RESULTS: At 0, 120, and 240 mins, serum levels of TNF-alpha were measured using a specific rat TNF-alpha ELISA kit. U-74389G-treated endotoxemic animals showed significantly reduced TNF-alpha release 120 mins after endotoxin challenge (control, 2.5+/-2.1 pg/mL; LPS, 4041+/-871 pg/mL; U-74389G, 1627+/-474 pg/mL [p < .05]). Two hundred forty minutes after LPS administration, TNF-alpha levels decreased, whereas values in the untreated LPS group remained twice as high as those in the U-74389G group (LPS, 863+/-182 pg/mL; U-74389G, 369+/-54 pg/mL [p < .05]). CONCLUSIONS: The study demonstrated that administration of U-74389G, which has radical-scavenging and membrane-stabilizing properties, decreased TNF-alpha release during endotoxemia. Thus, 21-aminosteroids may lend themselves to evaluation in the treatment of septic states.
