ABSTRACT Caryocar brasiliense Cambess., Caryocaraceae (pequi) is a typical Brazilian Cerrado tree. A previous study showed that the butanolic fraction of pequi leaves promotes endothelium-dependent relaxation mediated by nitric oxide and that it causes reversible hypotension in rats. In the present study, we investigated the cell signaling pathways associated with the butanolic fraction-induced nitric oxide release, and we characterized the chemical composition of its fraction. Vascular reactivity tests, a western blotting analysis, and a chemiluminescence assay were used to investigate the signaling pathways involved in the vasorelaxant effect of the butanolic fraction. Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry was used to characterize the butanolic fraction chemical composition. Vasorelaxation was mediated through the activation of the calmodulin and phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways, leading to subsequent endothelial nitric oxide synthase phosphorylation and nitric oxide production, as evidenced by western blotting and chemiluminescence assays, respectively. The chemical characterization of the butanolic fraction revealed the presence of 72 oxygenated compounds, whose molecular formulae are compatible with phenolic compounds, suggesting a potential contribution of these compounds for the butanolic fraction vasorelaxant effect. These findings show that the calmodulin and phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways are involved in the butanolic fraction-induced endothelial nitric oxide synthase activation and are promoted by polyphenol compounds present in the C. brasiliense leaves.

PRUPOSE: Bacterial translocation has been shown to occur in critically ill patients after extensive trauma, shock, sepsis, or thermal injury. The present study investigates mesenteric microcirculatory dysfunctions, the bacterial translocation phenomenon, and hemodynamic/metabolic disturbances in a rat model of intestinal obstruction and ischemia. METHODS: Anesthetized (pentobarbital 50 mg/kg, i.p.) male Wistar rats (250-350 g) were submitted to intestinal obstruction or laparotomy without intestinal obstruction (Sham) and were evaluated 24 hours later. Bacterial translocation was assessed by bacterial culture of the mesenteric lymph nodes (MLN), liver, spleen, and blood. Leukocyte-endothelial interactions in the mesenteric microcirculation were assessed by intravital microscopy, and P-selectin and intercellular adhesion molecule (ICAM)-1 expressions were quantified by immunohistochemistry. Hematocrit, blood gases, lactate, glucose, white blood cells, serum urea, creatinine, bilirubin, and hepatic enzymes were measured. RESULTS: About 86% of intestinal obstruction rats presented positive cultures for E. coli in samples of the mesenteric lymph nodes, liver, and spleen, and 57% had positive hemocultures. In comparison to the Sham rats, intestinal obstruction induced neutrophilia and increased the number of rolling (~2-fold), adherent (~5-fold), and migrated leukocytes (~11-fold); this increase was accompanied by an increased expression of P-selectin (~2-fold) and intercellular adhesion molecule-1 (~2-fold) in the mesenteric microcirculation. Intestinal obstruction rats exhibited decreased PaCO2, alkalosis, hyperlactatemia, and hyperglycemia, and increased blood potassium, hepatic enzyme activity, serum urea, creatinine, and bilirubin. A high mortality rate was observed after intestinal obstruction (83% at 72 h vs. 0% in Sham rats). CONCLUSION: Intestinal obstruction and ischemia in rats is a relevant model for the in vivo study of mesenteric microcirculatory dysfunction and the occurrence of bacterial translocation. This model parallels the events implicated in multiple organ dysfunction (MOD) and death.