Ursodeoxycholic and chenodeoxycholic bile acids attenuate systemic and liver inflammation induced by lipopolysaccharide in rats.

Bacterial lipopolysaccharide (LPS) induces general inflammation, by activating pathways involving cytokine production, blood coagulation, complement system activation, and acute phase protein release. The key cellular players are leukocytes and endothelial cells, that lead to tissue injury and organ failure. The aim of this study was to explore the anti-inflammatory, antioxidant, and cytoprotective properties of two bile acids, ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) in LPS-induced endotoxemia in rats. The experiment involved six distinct groups of Wistar rats, each subjected to different pretreatment conditions: control and LPS groups were pretreated with propylene glycol, as a bile acid solvent, while the other groups were pretreated with UDCA or CDCA for 10 days followed by an LPS injection on day 10. The results showed that both UDCA and CDCA reduced the production of pro-inflammatory cytokines: TNF-α, GM-CSF, IL-2, IFNγ, IL-6, and IL-1ß and expression of nuclear factor-κB (NF-κB) induced by LPS. In addition, pretreatment with these bile acids showed a positive impact on lipid profiles, a decrease in ICAM levels, an increase in antioxidant activity (SOD, |CAT, GSH), and a decrease in prooxidant markers (H2O2 and O2-). Furthermore, both bile acids alleviated LPS-induced liver injury. While UDCA and CDCA pretreatment attenuated homocysteine levels in LPS-treated rats, only UDCA pretreatment showed reductions in other serum biochemical markers, including creatine kinase, lactate dehydrogenase, and high-sensitivity troponin I. It can be concluded that both, UDCA and CDCA, although exerted slightly different effects, can prevent the inflammatory responses induced by LPS, improve oxidative stress status, and attenuate LPS-induced liver injury.

Anti-ganglioside monoclonal antibody AA4 selectively inhibits IgE-induced signal transduction pathways in rat basophilic leukemia cells.

In rat basophilic leukemia 2H3 (RBL-2H3) cells, mAb AA4 binds to two derivatives of ganglioside GD1b that associate with the Src family kinase p53/56lyn and a serine kinase. Pre-incubation of cells with mAb AA4 blocks immunoglobulin E (IgE) mediated histamine release. In the present study we investigated the effect of incubation with mAb AA4 on signal transduction events. In addition to stimulation of the high affinity IgE receptor (Fc epsilonRI), cells were also activated by the calcium ionophore A23187 and the acetylcholine agonist carbachol in RBL-2H3 cells transfected with the G protein-coupled m3 muscarinic receptor. Incubation of cells with mAb AA4 in a dose-dependent manner inhibited the following Fc epsilonRI-induced signal transduction events: the increase of intracellular free calcium, phosphoinositol breakdown, tyrosine phosphorylation of proteins including the beta- of Fc epsilonRI and secretion. However, there was no inhibition of degranulation or of these biochemical events when cells were stimulated with calcium ionophore or activated via a G protein-coupled pathway. Our results demonstrate that mAb AA4 selectively blocks Fc epsilonRI-induced cell activation at a very early step upstream of receptor tyrosine phosphorylation. As mAb AA4 has previously been found to bind to gangliosides associated with Fc epsilonRI, inhibition of very early biochemical events may be due to interaction of mAb AA4 with the Fc epsilonRI induced signal transduction cascade at the receptor level.

[Secondary occlusal traumatism. 1. Histopathological changes of periodontal tissues in experimental occlusal traumatism]. / Sekundarni okluzioni traumatizam. Histoloske promene periodoncijuma eksperimentalnih zivotinja.

Six and nine months after the experimental occlusal traumatism, the following histopathological changes of periodontal tissues were observed: --Disorganisation and necrosis of the collagen fibers, abundant cellular infiltration and dilatation of the blood vasels of the periodontium; --The periodontal space was enlarged. Directions of principal collagen fibers was changed. This was especially visible in the region of transeptal fibers; --The observed periodontal changes were correlated with the duration of inflammation and occlusal trauma. The longer these factors persisted the more extensive these periodontal changes occurred.