Trimethylamine N-oxide promotes hyperlipidemia acute pancreatitis via inflammatory response

Trimethylamine N-oxide (TMAO), a metabolite of gut microbiota, is involved in the regulation of lipid metabolism and inflammatory response; however, the role of TMAO in hyperlipidemia acute pancreatitis (HAP) is not clear. In this study, HAP mice were used as an animal model to explore the effects and possible mechanism of TMAO on HAP, which may provide new ideas for the treatment of HAP. Results found that the levels of triglycerides, total cholesterol, low-density lipoprotein cholesterol, nonestesterified fatty acid, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, α-amylase, TMAO, and flavin-containing monooxygenase 3 were significantly increased, the levels of high-density lipoprotein cholesterol and insulin were significantly decreased, and there was an obvious pancreatic injury and inflammatory response in the model group. The choline analogue 3,3-dimethyl-1-butanol (DMB) treatment reversed the changes of serum biochemical parameters, alleviated the pancreatic tissue injury, and reduced the levels of inflammatory cytokines. Further studies of toll-like receptor (TLR)/p-glycoprotein 65 (p65) pathway found that the expressions of TLR2, TLR4, and p-p65/p65 in the model group were significantly increased, which was more obvious after Escherichia coli (Migula) Castellani & Chalmers treatment, while activation of the TLR/p65 pathway was inhibited by DMB. The results indicated that TMAO promotes HAP by promoting inflammatory response through TLR/p65 signaling pathway, suggesting that TMAO may be a potential target of HAP.

S-ketamine alleviates carbon tetrachloride-induced hepatic injury and oxidative stress by targeting the Nrf2/HO-1 signaling pathway

The aim of the present study was to investigate the protective effect of S-ketamine (S-KET) against carbon tetrachloride (CCl4) - induced liver damage and oxidative stress, as well as to elucidate the related underlying mechanisms. Blood was collected to measure biochemical parameters (alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), total bilirubin (TB) and γ-glutamyltransferase (γ-GT)) and the liver was harvested for histopathological analysis of enzymes related to the antioxidant response (malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), and glutathione peroxidase (GSH-PX)). Liver cell apoptosis was evaluated using the TUNEL assay. In addition, the expression levels of apoptosis-related proteins and the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway were detected by Western blot analysis to explore potential mechanisms. S-KET protected the liver from CCl4-induced damage. The changes to the liver biochemical parameters (increased ALT, AST, ALP, TB, and γ-GT) and oxidative stress-related indicators (increased MDA; depleted SOD, GSH, and GSH-PX) induced by CCl4 were inhibited by S-KET. S-Ket also inhibited CCl4-induced cell apoptosis, the changes in expression of related proteins, and blocked CCl4-induced liver injury and oxidative stress via activation of the Nrf2/HO-1 signaling pathway. S-KET effectively protected the liver by inhibition of CCl4-induced damage via upregulation the Nrf2/HO-1 signaling pathway.

Rosuvastatin corrects oxidative stress and inflammation induced by LPS to attenuate cardiac injury by inhibiting the NLRP3/TLR4 pathway

Rosuvastatin has been found to possess antioxidant and anti-inflammatory properties. The aim of the current study was to evaluate whether rosuvastatin was effective in attenuating cardiac injury in lipopolysaccharide (LPS) - challenged mice and H9C2 cells and identify the underlying mechanisms, focusing on the nod-like receptor protein 3 (NLRP3)/toll-like receptor 4 (TLR4) pathway. Cardiac injury, cardiac function, apoptosis, oxidative stress, inflammatory response, and the NLRP3/TLR4 pathway were evaluated in both in vivo and in vitro studies. LPS-induced cardiomyocyte injury was markedly attenuated by rosuvastatin treatment, evidenced by increased cell proliferation of H9C2 cells, rescued cardiac function, and improved morphological changes in mice and reduced lactate dehydrogenase (LDH), creatine kinase MB fraction (CK-MB), and troponin I (cTnI) in serum. Apoptosis was clearly ameliorated in myocardial tissue and H9C2 cells co-treated with rosuvastatin. In addition, after LPS challenge, excessive oxidative stress was present, indicated by increases in malondialdehyde (MDA) content, NADPH activity, and reactive oxygen species (ROS) production and decreased superoxide dismutase (SOD) activity. Rosuvastatin improved all the indicators of oxidative stress, with an effect similar to that of N-acetylcysteine (NAC) (an ROS scavenger). Notably, LPS-exposed H9C2 cells and mice showed significant NLRP3 and TLR4/nuclear factor-κB (NF-κB) pathway activation and inflammatory responses. Administration of rosuvastatin reduced the increases in NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), pro-caspase-1, TLR4, and p65 expression and decreased the tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), IL-18, and IL-6 contents, with an effect similar to that of MCC950 (an NLRP3 inhibitor). In conclusion, inhibition of the inflammatory response and oxidative stress contributes to cardioprotective effect of rosuvastatin against cardiac injury induced by LPS, and the effect of rosuvastatin was achieved through inactivation of the NF-κB/NLRP3 pathway.

The role of microRNA-146a in regulating the expression of IRAK1 in cerebral ischemia-reperfusion injury

MicroRNA-146a (miR-146a) is reportedly implicated in the pathogenesis of ischemia-reperfusion (I/R) injury; however, its role in cerebral I/R injury is unclear and requires further investigation. In this study, cerebral I/R injury was established in mice via middle cerebral artery occlusion, and the expression of miR-146a was detected in the brain tissue via quantitative real-time PCR. We found that the expression of miR-146a was upregulated. Furthermore, the endogenous miR-146a was antagonized by its specific inhibitor. The results indicated that the inhibition of miR-146a deteriorated I/R-induced neurobehavioral impairment, exaggerated the infarct size, and exacerbated blood-brain barrier leakage. Cerebral I/R injury-induced generation of inflammatory cytokines, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, was further promoted by miR-146a inhibitor. The expression of interleukin-1 receptor associated kinase 1 (IRAK1), a target of miR-146a, was upregulated upon miR-146a inhibition. In addition, the nuclear factor κB (NF-κB) signaling pathway was over-activated when miR-146a was antagonized as manifested by the increased levels of phospho-NF-κB inhibitor α and nuclear p65. In summary, our findings demonstrate that the elevation of miR-146a may be one of the compensatory responses after the cerebral I/R injury and suggest miR-146a as a potential therapeutic target for cerebral I/R injury.