Quercetin, coenzyme Q10, and L-canavanine as protective agents against lipid peroxidation and nitric oxide generation in endotoxin-induced shock in rat brain

The present study was designed to evaluate the possible protective effect of quercetin, coenzyme Q10 (CoQ10), or L-canavanine treatments against endotoxin-induced shock in rat brain. Shock was induced by i.p. injection of 10 mg x kg(-1)of lipopolysaccharide (LPS) and was biochemically manifested 2 h after injection as an increase in brain malondialdehyde (MDA), total nitrite/nitrate (NO(x)), glutathione peroxidase (GSHPx), and blood lactate level/activity. On the other hand, endotoxemia resulted in reduced brain glutathione (GSH) and phospholipids' content as well as the serum sulfhydryl groups' (SH-group) value. Pretreatment with quercetin (200 mg x kg(-1)per os) 2 h before LPS injection diminished the shock-induced increases in brain MDA, and NO(x)levels while elevating the reduced brain phospholipids' and serum SH groups' content. CoQ10 administered at a dose of 200 mg x kg(-1)per os for 7 days prior to shock induction, reduced the elevated levels of brain MDA, NO(x), and GSHPx level/activity due to redundancy. The same treatment caused a 3-fold increase in the reduced brain GSH level and normalized the depressed phospholipids' content. Treatment of animals with L-canavanine (50 mg x kg(-1)i.p.) simultaneously with LPS injection, reduced the elevated level of blood lactate. Brain superoxide dismutase (SOD) level was neither affected by endotoxin nor by different treatments. In conclusion, this study indicates that SOD may not reflect the level of peroxidation and points to the value of quercetin, CoQ10, and L-canavanine in ameliorating the oxidative status of brain during the early phase of endotoxic shock.

Calcium and reactive oxygen species as messengers in endotoxin action on adrenocortical cells

The effect of Escherichia coli 0111:B4 endotoxin (lipopolysaccharide, LPS) on the intracellular Ca2+ and reactive oxygen metabolite content of both rat isolated fasciculata-reticularis and glomerulosa cells was evaluated by flow cytometry to know the role of these mechanisms in the initiation of cell injury produced by LPS on adrenocortical cells during endotoxic shock. A rapid increase of intracellular calcium was induced by endotoxin in both cell types. In fasciculata-reticularis cells, this [Ca2+]i increase was mainly due to an important mobilization of intracellular stores. Dose-dependent increases in [Ca2+]i were also observed when both cell types were incubated with LPS for 20 min in the presence of extracellular calcium. This treatment abolished the increase in intracellular calcium induced by ACTH and angiotensin II. On the other hand, the endotoxin produced a fast and dose-dependent increase in reactive oxygen species in both cell types, higher in glomerulosa than in fasciculata-reticularis cells. LPS-pretreated cells showed more susceptibility to the oxidative stress induced by Fe2+. These results can be related to functional alterations previously described showing the involvement of calcium and reactive oxygen species as messengers in the endotoxin action on adrenocortical cells.

Studies of endotoxin-dependent fever in pre-pubertal pigs following acute activation of the pituitary-adrenocortical axis: towards a new hypothesis of fever regulation

The possibility that adrenocortical activation might alter the pyretic effects of bacterial lipopolysaccharide endotoxin in growing pigs was investigated. In a series of four experiments, animals received increasing doses of porcine adrenocorticotrophic hormone ACTH (1.5, 4.5, 13.5 IU kg-1) or CRH (7 microg kg-1), all of which markedly affected cortisol release. Unexpectedly, these treatments tended to increase body temperature during the early and middle stages of the febrile response, although they did appear to induce an earlier deferscence. These results suggest that acute stress may not modify fever induced by immunological challenge, although a different situation could obtain during chronic stress. Furthermore, a hypothesis of fever regulation is proposed which attempts to reconcile the present findings with those from previous studies in swine.