Dj. Loegering et al., EFFECT OF IGG-COATED ERYTHROCYTES AND LIPOPOLYSACCHARIDE (LPS) TOLERANCE ON THE DEPRESSION OF VASCULAR REACTIVITY CAUSED BY LPS, Shock, 2(3), 1994, pp. 192-195
Previous studies have shown that the injection of IgG-coated erythrocy
tes (EIgG) increased the mortality rate caused by bacterial lipopolysa
ccharide (LPS) and that animals made tolerant to LPS show a decrease i
n the mortality rate caused by LPS. The present study determined the e
ffect of the injection of EIgG and of LPS tolerance on the depression
of vascular reactivity caused by LPS in vivo or in vitro. For in vivo
studies, LPS was injected intravenously into rats 2 h after the inject
ion of E or EIgG. Aortae were removed 90 min after the injection of LP
S, and cumulative concentration-response curves to phenylephrine were
performed in helically cut aortic strips. LPS (.1 mg/kg) caused a 21%
decrease in the maximum tension developed in response to phenylephrine
in aortae from animals given erythrocytes. In contrast, animals given
EIgG showed a 63% decrease in maximum tension following the injection
of this dose of LPS. For in vitro studies, the depression of vascular
reactivity caused by incubation with LPS of aortae from rats injected
with EIgG was determined. As with the in vivo studies, there was a gr
eater depression of vascular reactivity caused by incubation with LPS
of aortae taken from animals injected with EIgG. Similar studies were
carried out with rats made tolerant to LPS. Tolerance was induced by g
iving a regimen of five daily injections of LPS. Following the injecti
on of LPS (1 mg/kg), the maximum tension of aortae from sham tolerant
animals was depressed 63%, while aortae from LPS tolerant animals were
depressed only 16%. LPS tolerance completely prevented the depression
of maximum tension caused by incubation of aortae with LPS. Thus, the
injection of EIgG exacerbates and LPS tolerance abates the LPS-stimul
ated depression of vascular reactivity. These changes in vascular reac
tivity may contribute to the effects that the injection of EIgG and LP
S tolerance have on the survival rate following LPS administration.