BACKGROUND: Intestinal mucosal hypoperfusion and loss of barrier function during sepsis may contribute to maintaining the septic state. Free radicals are produced during sepsis and antioxidants improve survival from experimental sepsis. It is unclear whether endothelial cell injury from free radicals results in altered microvascular reactivity. Lazaroids are antioxidants which scavenge radicals and block lipid radical chain reactions. The authors sought to determine whether lazaroids altered the intestinal microvascular responses to sepsis. METHODS: In vivo video microscopy was used to study the ileal microcirculation of the rat. A1 (inflow) arteriolar diameter and flow, A3 (premucosal) arteriolar diameters, and cardiac output were measured. Lazaroid or vehicle was infused before a bolus injection of live Escherichia coli or saline. RESULTS: Lazaroid alone had no effect on the intestinal vessels or haemodynamics. E. coli caused vasoconstriction (A1, -21 per cent, A3, -19 per cent of baseline) and hypoperfusion (-36 per cent) despite increased cardiac output (+31 per cent). Lazaroid significantly attenuated both constriction (A1, -11 per cent; A3, 10 to -1 per cent) and hypoperfusion (-15 per cent), but did not increase cardiac output (30 per cent). CONCLUSION: E. coli bacteraemia led to intestinal vasoconstriction and hypoperfusion. Lazaroid reduced this effect without altering central haemodynamic responses, suggesting that free radicals have a deleterious effect on the intestinal microcirculation during bacteraemia.
BACKGROUND: Intestinal mucosal hypoperfusion and loss of barrier function during sepsis may contribute to maintaining the septic state. Free radicals are produced during sepsis and antioxidants improve survival from experimental sepsis. It is unclear whether endothelial cell injury from free radicals results in altered microvascular reactivity. Lazaroids are antioxidants which scavenge radicals and block lipid radical chain reactions. The authors sought to determine whether lazaroids altered the intestinal microvascular responses to sepsis. METHODS: In vivo video microscopy was used to study the ileal microcirculation of the rat. A1 (inflow) arteriolar diameter and flow, A3 (premucosal) arteriolar diameters, and cardiac output were measured. Lazaroid or vehicle was infused before a bolus injection of live Escherichia coli or saline. RESULTS:Lazaroid alone had no effect on the intestinal vessels or haemodynamics. E. coli caused vasoconstriction (A1, -21 per cent, A3, -19 per cent of baseline) and hypoperfusion (-36 per cent) despite increased cardiac output (+31 per cent). Lazaroid significantly attenuated both constriction (A1, -11 per cent; A3, 10 to -1 per cent) and hypoperfusion (-15 per cent), but did not increase cardiac output (30 per cent). CONCLUSION: E. coli bacteraemia led to intestinal vasoconstriction and hypoperfusion. Lazaroid reduced this effect without altering central haemodynamic responses, suggesting that free radicals have a deleterious effect on the intestinal microcirculation during bacteraemia.