Abstract
BackgroundThe supraceliac aortic cross-clamping can be an option to save patients with hipovolemic shock due to abdominal trauma. However, this maneuver is associated with ischemia/reperfusion (I/R) injury strongly related to oxidative stress and reduction of nitric oxide bioavailability. Moreover, several studies demonstrated impairment in relaxation after I/R, but the time course of I/R necessary to induce vascular dysfunction is still controversial. We investigated whether 60 minutes of ischemia followed by 30 minutes of reperfusion do not change the relaxation of visceral arteries nor the plasma and renal levels of malondialdehyde (MDA) and nitrite plus nitrate (NOx).MethodsMale mongrel dogs (n = 27) were randomly allocated in one of the three groups: sham (no clamping, n = 9), ischemia (supraceliac aortic cross-clamping for 60 minutes, n = 9), and I/R (60 minutes of ischemia followed by reperfusion for 30 minutes, n = 9). Relaxation of visceral arteries (celiac trunk, renal and superior mesenteric arteries) was studied in organ chambers. MDA and NOx concentrations were determined using a commercially available kit and an ozone-based chemiluminescence assay, respectively.ResultsBoth acetylcholine and calcium ionophore caused relaxation in endothelium-intact rings and no statistical differences were observed among the three groups. Sodium nitroprusside promoted relaxation in endothelium-denuded rings, and there were no inter-group statistical differences. Both plasma and renal concentrations of MDA and NOx showed no significant difference among the groups.ConclusionSupraceliac aortic cross-clamping for 60 minutes alone and followed by 30 minutes of reperfusion did not impair relaxation of canine visceral arteries nor evoke biochemical alterations in plasma or renal tissue.
Highlights
The supraceliac aortic cross-clamping can be an option to save patients with hipovolemic shock due to abdominal trauma
Despite a good understanding about the pathogenesis of I/R injury, the time course of I/R necessary to induce vascular dysfunction is still controversial [12,13,14,15]. This fact motivated us to investigate whether 60 minutes of ischemia followed by 30 minutes of reperfusion do not change the endothelium-dependent and -independent relaxation of visceral arteries nor the plasma and renal levels of malondialdehyde (MDA, an index of lipid peroxidation) and nitrite plus nitrate (NOx)
Values were considered to be statistically significant at p values less than 0.05. Vascular function Both Ach and A23187 caused concentration-dependent relaxation in endothelium-intact rings of celiac trunk, renal and superior mesenteric arteries and no statistical differences were observed among the three groups (Figures 1 and 2)
Summary
The supraceliac aortic cross-clamping can be an option to save patients with hipovolemic shock due to abdominal trauma This maneuver is associated with ischemia/reperfusion (I/R) injury strongly related to oxidative stress and reduction of nitric oxide bioavailability. Despite a good understanding about the pathogenesis of I/R injury, the time course of I/R necessary to induce vascular dysfunction is still controversial [12,13,14,15] This fact motivated us to investigate whether 60 minutes of ischemia (simulating the clinical time of supraceliac aortic cross-clamping for surgical control of bleeding) followed by 30 minutes of reperfusion do not change the endothelium-dependent and -independent relaxation of visceral arteries nor the plasma and renal levels of malondialdehyde (MDA, an index of lipid peroxidation) and nitrite plus nitrate (NOx). If our hypothesis is true, efforts should be made to establish an effective treatment protocol to prevent the organ failure in this period
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