Objective: This study tests whether sialic acid is a mediator of the lung injury following lower extremity ischemia/reperfusion (I/R). Design. Prospective randomised study.
Materials and methods: Thirty-one Sprague-Dawley rats were randomised into four groups: group 1, aorta was exposed but not clamped; group 2, aorta clamped for 3 h, followed by 1 h of reperfusion; group 3, 50 mg/kg pentoxifylline administrated before the aorta was clamped; and group 4, 1 mg/kg dexametasone administrated before the aorta was clamped. Serial arterial blood samples for blood gas, tumor necrosis factor-alpha (TNF-alpha), and total SA (TSA) assay were obtained. The lungs were removed and histologically examined for evidence of injury.
Results: Groups 2, 3, and 4 had significantly higher peak serum TSA concentrations compared with groups 1 (group 1 vs. 2, p=0.001; group 1 vs. 3, p=0.002; group 1 vs. 4, p=0.001). Group 3 had lower peak serum TSA concentration. Groups 2 and 4 had significantly higher peak serum TNF-alpha concentrations (p=0.0001) compared with groups 1 and 3. Group 3 had lower peak serum TNF-alpha concentration. Lower TSA and TNF-alpha levels are associated with lesser degrees of lung injury.
Conclusions: TSA and TNF appear during events that lead to lung injury following lower extremity I/R.