Protective effect ofp-methoxyl-diphenyl diselenide in lethal acute liver failure induced by lipopolysaccharide and d-galactosamine in mice

Toxicology and pharmacology of synthetic organoselenium compounds: an update

Here, we addressed the pharmacology and toxicology of synthetic organoselenium compounds and some naturally occurring organoselenium amino acids. The use of selenium as a tool in organic synthesis and as a pharmacological agent goes back to the middle of the nineteenth and the beginning of the twentieth centuries. The rediscovery of ebselen and its investigation in clinical trials have motivated the search for new organoselenium molecules with pharmacological properties. Although ebselen and diselenides have some overlapping pharmacological properties, their molecular targets are not identical. However, they have similar anti-inflammatory and antioxidant activities, possibly, via activation of transcription factors, regulating the expression of antioxidant genes. In short, our knowledge about the pharmacological properties of simple organoselenium compounds is still elusive. However, contrary to our early expectations that they could imitate selenoproteins, organoselenium compounds seem to have non-specific modulatory activation of antioxidant pathways and specific inhibitory effects in some thiol-containing proteins. The thiol-oxidizing properties of organoselenium compounds are considered the molecular basis of their chronic toxicity; however, the acute use of organoselenium compounds as inhibitors of specific thiol-containing enzymes can be of therapeutic significance. In summary, the outcomes of the clinical trials of ebselen as a mimetic of lithium or as an inhibitor of SARS-CoV-2 proteases will be important to the field of organoselenium synthesis. The development of computational techniques that could predict rational modifications in the structure of organoselenium compounds to increase their specificity is required to construct a library of thiol-modifying agents with selectivity toward specific target proteins.

The hypolipidemic action of a diet supplemented with p,p'-methoxyl-diphenyl diselenide is not directly related to its antioxidant property

The present study investigated whether a p,p'-methoxyl-diphenyl diselenide (MeOPhSe)2-supplemented diet causes toxicity in rats. A second aim of this study was to determine whether a 10 ppm (MeOPhSe)2-supplemented diet has hypolipidemic effect on Triton WR-1339-induced hyperlipidemia in rats. To rule out the antioxidant property of (MeOPhSe)2 in its hypolipidemic action, parameters of oxidative stress were carried out. Wistar rats were fed with 3, 10, or 30 ppm of (MeOPhSe)2-supplemented diet for 30 days. None of (MeOPhSe)2-supplemented diets caused alteration in general parameters of toxicity and lipid profile of rats. The hypolipidemic effect of 10 ppm of (MeOPhSe)2-supplemented diet on rats treated with Triton WR-1339 (400 mg/kg, intraperitoneal) was investigated. The (MeOPhSe)2-supplemented diet partially protected against the levels of total cholesterol (TC) and non-HDL-C and reduced the atherogenic index (AI) increased by Triton WR-1339 in rats. A positive correlation between TC and triglyceride levels (r = 0.679) and non-HDL-C levels (r = 0.929) and AI (r = 0.889) was demonstrated. Triton WR-1339 altered parameters of oxidative stress in livers of rats but (MeOPhSe)2-supplemented diet did not protect against these alterations. The results demonstrated that the hypolipidemic action of (MeOPhSe)2-supplemented diet is not directly related to its antioxidant property and devoid of systemic toxicity in rats at the parameters analyzed.

Cerium oxide nanoparticles alleviate oxidative stress and decreases Nrf-2/HO-1 in D-GALN/LPS induced hepatotoxicity

Translocation of the master regulator of antioxidant-response element-driven antioxidant gene, nuclear factor erythroid 2 (Nrf-2) from the cytoplasm into the nucleus and triggering the transcription of hemoxygenase-1 (HO-1) to counteract the oxidative stress is a key feature in D-galactoseamine and lipopolysaccharide (D-GALN/LPS) induced hepatotoxicity. We mainly aimed to study the effect of cerium oxide (CeO2) nanoparticles on Nrf-2/HO-1 pathway whereas; it has previously shown to have an antioxidant effect in liver models. Administration of CeO2 nanoparticles significantly decreased the translocation of the cytoplasmic Nrf-2 with a concomitant decrement in the gene expression of HO-1 as it reveals a powerful antioxidative effect as indicated by the significant increase in the levels of glutathione (GSH), glutathione peroxidase (GPX1), glutathione reductase (GR), superoxide dismutase (SOD) and catalase. In synchronization, a substantial decrement in the levels of inducible nitric oxide synthase (iNOS), TBARS and percentage of DNA fragmentation was established. These results were confirmed by histopathology examination which showed a severe degeneration, haemorrhages, widened sinusoids and focal leukocyte infiltration in D-GALN/LPS treatment and these features were alleviated with CeO2 administration. In conclusion, CeO2 is a potential antioxidant that can effectively decrease the translocation of the cytoplasmic Nrf-2 into the nucleus and decrease HO-1 in D-GALN/LPS induced hepatotoxicity.

Triptolide attenuate the oxidative stress induced by LPS/D-GalN in mice

Triptolide, a diterpene triepoxide, is one of the major components of most functional extracts of Tripterygium wilfordii Hook f, which is known to have various biological effects, including immunosuppressive, anti-inflammatory and anti-tumor functions. We studied the inhibitory effect of triptolide on endotoxemia (ETM)-induced oxidative stress, which was induced in C57BL/6 mice by lipopolysaccharide (LPS) and D-galactosamine (D-GalN). Pretreatment with triptolide decreased the reactive oxygen species (ROS) levels, mortality rate and liver injury after LPS/D-GalN injection. We utilized comprehensive proteomics to identify alterations in liver protein expression during pretreatment with triptolide or N-acetylcysteine (NAC) after LPS/D-GalN injection, 44 proteins were found to be related to oxidative stress, mitochondria, metabolism and signal transduction, and 23 proteins of them seemed to be significantly up- or down-regulated. Furthermore, both triptolide and NAC inhibited activation of c-jun NH2-terminal kinases (JNK) and mitogen-activated protein kinase p38 (p38), phosphorylation of inhibitor of nuclear factor-kappa B (IκB) and activation of nuclear factor-κB (NF-κB). These results demonstrated that triptolide inhibited the activation of JNK and p38 by decreasing ROS levels, which in turn inhibited the hepatic injury. In addition, we set and validated the phosphorylation model of extracellular signal-regulated kinase (ERK) and proposed that triptolide probably induced ERK phosphorylation through inhibiting its dephosphorylation rates. These results showed that triptolide can effectively reduce the oxidative stress and partially rescue the damage in the liver induced by LPS/D-GalN.

Protective effect of chloral hydrate against lipopolysaccharide/D-galactosamine-induced acute lethal liver injury and zymosan-induced peritonitis in mice

In recent years, certain anesthetics have been shown to have protective effects against acute inflammation in experimental animals, an observation that may yield new options for adjunctive treatment of acute inflammation. In this study, we investigated the effects of chloral hydrate (CH) on the acute inflammatory response in BALB/c mice using lipopolysaccharide/D-galactosamine (LPS/D-GalN)-induced acute lethal liver injury and zymosan A-induced peritonitis models. The survival of mice following LPS/D-GalN treatment was significantly improved by a single injection with chloral hydrate, which could be administered simultaneously or as late as 3h after challenge with LPS/D-GalN; liver injury was also attenuated. A sharp rise in serum levels of MCP-1, IL-6 and TNF-alpha was attenuated or delayed after chloral hydrate treatment. Furthermore, the mechanism by which chlorate hydrate inhibits inflammation was associated with an attenuated increase in nuclear factor kappaappaB (NF-kappaB) activity in NF-kappaB-RE-luc mice upon LPS/D-GalN treatment. In mice with acute peritonitis, leukocyte number and protein concentration in peritoneal exudates peaked with a 16h lag, and serum levels of MCP-1, IL-6 and TNF-alpha were significantly lower at certain time points in the chloral hydrate-treated group compared to those in the normal saline (NS)-treated control group. In addition, chloral hydrate treatment in vitro attenuated the upregulation of TNF-alpha and IL-6 by peritoneal macrophages and NF-kappaB activity in RAW264.7 cells stimulated with LPS, suggesting that monocytes/macrophages may be a target of chloral hydrate. These results indicate that chloral hydrate has a protective effect against LPS/D-GalN-induced acute lethal liver injury in mice, which may be associated with an inhibition of NF-kappaB activity and delays in proinflammatory cytokine production. However, this phenomenon was not associated with levels of serum corticosterone. Chloral hydrate also attenuated the inflammatory response in zymosan A-induced acute peritonitis, a model of mild inflammation. In conclusion, treatment with only a single injection of chloral hydrate could significantly attenuate acute inflammation in mice treated with LPS/D-GalN and zymosan A. These effects are also likely associated with the inhibition of NF-kappaB activity.