Effects of lipid A analogues of the strains of E. coli on complement and myeloperoxidase activation in myocardial reperfusion following ischaemia in rats

The aim of the study was to evaluate the ability of lipid A analogues obtained from the native strain (LAS) or strains of E. coli resistant to either an amine oxide (modLANO) or to a quaternary ammonium salt (modLBr) to reduce myocardial ischaemia and reperfusion injury in rats. The 0.5, 2, 4, 24 h pretreatment of rats with lipid A from a strain of E. coli resistant to an amine oxide (modLANO 0.5 mg/kg i.v.) in an in vitro model of myocardial ischemia lasting 10 min followed by 10 min reperfusion did not reduce the myeloperoxidase (MPO) and complement activities. In an in vivo study, the 24 h pretreatment of rats with modLANO in a dose of 0.5 mg/kg i.v. only significantly decreased both the MPO and complement activities in serum (p<0.01). The analogues of lipid A indicate abilities to influence the myocardial ischaemia-reperfusion injury in times-dependent and structures-dependent ways.