Thioacetamide (TAA) is widely used in the production of drugs, pesticides and dyeing auxiliaries. Moreover, it is a chemical that can cause liver damage and cancer. TAA has recently been identified to cause bone damage in animal models. However, the type of bone damage that TAA causes and its potential pathogenic mechanisms remain unclear. The toxic effects of TAA on the femurs of New Zealand white rabbits and the underlying toxicity mechanism were investigated in this study. Serum samples, the heart, liver, kidney and femurs were collected from rabbits after intraperitoneal injection of TAA for 5 months (100 and 200 mg/kg). The New Zealand white rabbits treated with TAA showed significant weight loss and femoral shortening. The activities of total bilirubin, total bile acid and gamma-glutamyl transpeptidase in the serum were increased following treatment with TAA. In addition, thinned cortical bone and significantly decreased trabecular thickness of TAA-treated rabbits was observed, which was accompanied by significantly decreased mineral density of the cortical and trabecular bone. Moreover, there was a significant decrease in modulus of elasticity and maximum load on bone stress in TAA-treated rabbits. The western blotting results showed that the expression of phosphorylated (p)-p38 and p-ERK in femur tissues of rabbits were increased after TAA administration. Collectively, these results suggested that TAA may lead to femoral damage in rabbits by activating the p38/ERK signaling pathway.
- MeSH
- femur MeSH
- játra * metabolismus MeSH
- králíci MeSH
- MAP kinasový signální systém MeSH
- signální transdukce MeSH
- thioacetamid * MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Histone deacylase 11 and human sirtuins are able to remove fatty acid-derived acyl moieties from the ε-amino group of lysine residues. Specific substrates are needed for investigating the biological functions of these enzymes. Additionally, appropriate screening systems are required for identification of modulators of enzymatic activities of HDAC11 and sirtuins. We designed and synthesized a set of activity probes by incorporation of a thioamide quencher unit into the fatty acid-derived acyl chain and a fluorophore in the peptide sequence. Systematic variation of both fluorophore and quencher position resulted "super-substrates" with catalytic constants of up to 15,000,000 M-1s-1 for human sirtuin 2 (Sirt2) enabling measurements using enzyme concentrations down to 100 pM in microtiter plate-based screening formats. It could be demonstrated that the stalled intermediate formed by the reaction of Sirt2-bound thiomyristoylated peptide and NAD+ has IC50 values below 200 pM.
- MeSH
- fluorescenční barviva chemie farmakologie MeSH
- fotochemické procesy MeSH
- histondeacetylasy chemie genetika metabolismus MeSH
- lidé MeSH
- molekulární struktura MeSH
- pozitronová emisní tomografie * MeSH
- sirtuiny antagonisté a inhibitory chemie metabolismus MeSH
- thioamidy chemie farmakologie MeSH
- transport elektronů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Acute liver failure (ALF) is known for extremely high mortality rate, the result of widespread damage of hepatocytes. Orthotopic liver transplantation is the only effective therapy but its application is limited by the scarcity of donor organs. Given the importance in the liver biology of Wnt/beta-catenin signaling pathway, we hypothesized that its stimulation could enhance hepatocyte regeneration and attenuate the course of thioacetamide (TAA)-induced ALF in Lewis rats. Chronic treatment with Wnt agonist was started either immediately after hepatotoxic insult ("early treatment") or when signs of ALF had developed ("late treatment"). Only 23 % of untreated Lewis rats survived till the end of experiment. They showed marked increases in plasma alanine aminotransferase (ALT) activity and bilirubin and ammonia (NH3) levels; plasma albumin decreased significantly. "Early" and "late" Wnt agonist treatment raised the final survival rate to 69 % and 63 %, respectively, and normalized ALT, NH3, bilirubin and albumin levels. In conclusion, the results show that treatment with Wnt agonist attenuates the course of TAA-induced ALF in Lewis rats, both with treatment initiated immediately after hepatotoxic insult and in the phase when ALF has already developed. Thus, the pharmacological stimulation of Wnt/beta-catenin signaling pathway can present a new approach to ALF treatment.
- MeSH
- akutní selhání jater chemicky indukované farmakoterapie metabolismus MeSH
- beta-katenin metabolismus MeSH
- játra účinky léků metabolismus MeSH
- potkani inbrední LEW MeSH
- preklinické hodnocení léčiv MeSH
- proteiny Wnt agonisté MeSH
- signální dráha Wnt účinky léků MeSH
- thioacetamid MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Acute liver failure (ALF) is a clinical syndrome with high mortality rate, resulting from widespread hepatocyte damage. Its pathophysiological background is still poorly understood and preclinical studies evaluating pathophysiology and new potential therapeutic measures are needed. The model of ALF induced by administration of thioacetamide (TAA) in Lewis rats is recommended as optimal; however, the limitation of previous studies was that they were performed predominantly in male rats. In view of the growing recognition that sex as a biological variable should be taken into consideration in preclinical research, we examined its role in the development of TAA-induced ALF in Lewis rats. We found that, first, intact male Lewis rats showed lower survival rate than their female counterparts, due to augmented liver injury documented by higher plasma ammonia, and bilirubin levels and alanine aminotransferase activity. Second, in female rats castration did not alter the course of TAA-induced ALF whereas in the male gonadectomy improved the survival rate and attenuated liver injury, reducing it to levels observed in their female counterparts. In conclusion, we found that Lewis rats show a remarkable sexual dimorphism with respect to TAA-induced ALF, and male rats display dramatically poorer prognosis as compared with the females. We showed that testosterone is responsible for the deterioration of the course of TAA-induced ALF in male rats. In most general terms, our findings indicate that in the preclinical studies of the pathophysiology and treatment of ALF (at least of the TAA-induced form) the sex-linked differences should be seriously considered.
- MeSH
- akutní selhání jater chemicky indukované metabolismus patologie MeSH
- karcinogeny toxicita MeSH
- krysa rodu rattus MeSH
- modely nemocí na zvířatech MeSH
- potkani inbrední LEW MeSH
- sexuální faktory MeSH
- testosteron metabolismus MeSH
- thioacetamid toxicita MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
We developed a one-step direct assay for the determination of histone deacylase (HDAC) activity by substituting the carbonyl oxygen of the acyl moiety with sulfur, resulting in thioacylated lysine side chains. This modification is recognized by class I HDACs with different efficiencies ranging from not accepted for HDAC1 to kinetic constants similar to that of the parent oxo substrate for HDAC8. Class II HDACs can hydrolyze thioacylated substrates with approximately 5-10-fold reduced kcat values, which resembles the effect of thioamide substitution in metallo-protease substrates. Class IV HDAC11 accepts thiomyristoyl modification less efficiently with an ∼5-fold reduced specificity constant. On the basis of the unique spectroscopic properties of thioamide bonds (strong absorption in spectral range of 260-280 nm and efficient fluorescence quenching), HDAC-mediated cleavage of thioamides could be followed by ultraviolet-visible and fluorescence spectroscopy in a continuous manner. The HDAC activity assay is compatible with microtiter plate-based screening formats up to 1536-well plates with Z' factors of >0.75 and signal-to-noise ratios of >50. Using thioacylated lysine residues in p53-derived peptides, we optimized substrates for HDAC8 with a catalytic efficiency of >250000 M-1 s-1, which are more than 100-fold more effective than most of the known substrates. We determined inhibition constants of several inhibitors for human HDACs using thioacylated peptidic substrates and found good correlation with the values from the literature. On the other hand, we could introduce N-methylated, N-acylated lysine residues as inhibitors for HDACs with an IC50 value of 1 μM for an N-methylated, N-myristoylated peptide derivative and human HDAC11.
- MeSH
- biokatalýza MeSH
- histondeacetylasy chemie genetika metabolismus MeSH
- inhibitory histondeacetylas chemie metabolismus MeSH
- kinetika MeSH
- lidé MeSH
- lysin chemie metabolismus MeSH
- thioamidy chemie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A new thiourea ligand (HL), namely N-(4-chlorophenyl)morpholine-4-carbothioamide and its Co(III), Ni(II) and Ag(I) complexes (1a, 1b and 1c) were synthesized and investigated by Fourier-transform infrared, 1H NMR and UV-visible spectroscopies. The compounds HL and 1c were characterized by single-crystal X-ray crystallography revealing the triclinic space group P[Formula: see text] for both compounds. The inhibitory effect of HL ligand, 1a, 1b, and 1c complexes was investigated with in vitro tests on Gram-positive and Gram-negative bacteria. For the 1c complex, the results showed that the coordination of the HL to Ag(I) ion increased its antibacterial effect especially against E. coli. The assays also indicated that for the same bacteria strains, the new complexes showed higher activity than the ligand, with the relative activity 1c > 1b > 1a > HL. Moreover, all samples were more suitable antimicrobial agents against the Gram-negative than those of the Gram-positive bacteria. Eventually, the relationship between the structure and bactericidal activities of these specimens was examined by calculating frontier molecular orbital (HOMO and LUMO) energies using density functional theory method at the 6-31 G*/LANL2DZ level of theory.
- MeSH
- antibakteriální látky chemická syntéza chemie farmakologie MeSH
- gramnegativní bakterie účinky léků MeSH
- grampozitivní bakterie účinky léků MeSH
- komplexní sloučeniny chemická syntéza chemie farmakologie MeSH
- krystalografie rentgenová MeSH
- magnetická rezonanční spektroskopie MeSH
- mikrobiální testy citlivosti MeSH
- molekulární struktura MeSH
- morfoliny chemická syntéza chemie farmakologie MeSH
- spektrofotometrie ultrafialová MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- thioamidy chemická syntéza chemie farmakologie MeSH
- thiomočovina metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
AIM/BACKGROUND: Pistacia terebinthus is used as a coffee substitute in the East and Southern Anatolia regions of Turkey. It contains unsaturated fatty acids, tocopherols, polyphenols and carotenoids. P. terebinthus has anti-inflammatory and potential antioxidant activity. In this study we evaluated the protective effects of P. terebinthus coffee (PTC) on thioacetamide (TAA)-induced liver injury in rats. MATERIALS AND METHODS: Twenty-eight male Sprague-Dawley rats were equally randomized into four groups. Chronic liver injury was induced with TAA (100 mg/kg i.p. three times weekly). The first group of rats served as control and received only tap water (G1), and the remaining groups of rats received PTC, p.o (G2); TAA (G3); TAA plus PTC, p.o (G4), respectively. RESULTS: After 8 weeks, PTC intake significantly reduced fibrosis/inflammation scores (p PTC intake reduced transforming growth factor beta (TGF-β) concentrations in the liver (p PTC intake. DISCUSSION AND CONCLUSION: PTC intake provided beneficial effects against TAA-induced liver injury in rats. PTC probably suppresses the proinflammatory cytokines through NF-κB signaling pathway.
- MeSH
- antioxidancia farmakologie MeSH
- bylinné čaje * MeSH
- experimentální cirhóza jater * chemicky indukované metabolismus patofyziologie prevence a kontrola MeSH
- játra * účinky léků metabolismus patologie MeSH
- krysa rodu rattus MeSH
- modely nemocí na zvířatech MeSH
- noxy toxicita MeSH
- oxidační stres účinky léků MeSH
- Pistacia * MeSH
- potkani Sprague-Dawley MeSH
- thioacetamid toxicita MeSH
- transformující růstový faktor beta metabolismus MeSH
- triterpeny farmakologie MeSH
- výsledek terapie MeSH
- zánět farmakoterapie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Acute liver failure (ALF) is a clinical syndrome resulting from widespread damage of hepatocytes, with extremely high mortality rate. Urgent orthotopic liver transplantation was shown to be the most effective therapy for ALF but this treatment option is limited by scarcity of donor organs. Therefore, hepatocyte transplantation (Tx) has emerged as a new therapeutical measure for ALF, however, the first clinical applications proved unsatisfactory. Apparently, extensive preclinical studies are needed. Our aim was to examine if hepatocytes isolated from transgenic "firefly luciferase" Lewis rats into the recipient liver would attenuate the course of thioacetamide (TAA)-induced ALF in Lewis rats. Untreated Lewis rats after TAA administration showed a profound decrease in survival rate; no animal survived 54 h. The rats showed marked increases in plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, in plasma level of bilirubin and ammonia (NH(3)), and in a significant decrease in plasma albumin. Hepatocyte Tx attenuated the course of TAA-induced ALF Lewis rats which was reflected by improved survival rate and reduced degree of liver injury showing as lowering of elevated plasma ALT, AST, NH(3) and bilirubin levels and increasing plasma albumin. In addition, bioluminescence imaging analyses have shown that in the TAA-damaged livers the transplanted hepatocyte were fully viable throughout the experiment. In conclusion, the results show that hepatocyte Tx into the liver can attenuate the course of TAA-induced ALF in Lewis rats. This information should be considered in attempts to develop new therapeutic approaches to the treatment of ALF.
- MeSH
- akutní selhání jater chemicky indukované mortalita terapie MeSH
- hepatocyty transplantace MeSH
- krysa rodu rattus MeSH
- míra přežití trendy MeSH
- potkani inbrední LEW MeSH
- thioacetamid toxicita MeSH
- transplantace buněk metody MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Acute liver failure (ALF) is a clinical condition with very high mortality rate. Its pathophysiological background is still poorly understood, which necessitates a search for optimal experimental ALF models with features resembling those of the human disorder. Taking into consideration reproducibility of induction of ALF, adequate animal size, cost of animals, the required time gap between insult and death of animals ("therapeutic window"), potential risk to investigator and other aspects, administration of thioacetamide (TAA) in rats is currently most recommended. However, the fundamental details of this ALF model have not yet been evaluated. This prompted us to investigate, first, the course of ALF as induced by intraperitoneal TAA at doses increasing from 175 to 700 mg/kg BW per day. The animals' survival rate, plasma alanine and aspartate aminotransferase activities, and bilirubin and ammonia levels were determined over the follow-up period. Second, we examined whether Wistar and Lewis rats exhibit any differences in the course of ALF induced by different TAA doses. We found that the optimal dose for ALF induction in rats is 350 mg.kg(-1) i.p., given as a single injection. Wistar rats proved more susceptible to the development of TAA-induced ALF compared with Lewis rats. Collectively, our present findings provide a sound methodological background for experimental studies aimed at evaluation of pathophysiology and development of new approaches in the therapy of ALF.
- MeSH
- akutní selhání jater chemicky indukované patologie MeSH
- druhová specificita MeSH
- játra patologie MeSH
- karcinogeny aplikace a dávkování toxicita MeSH
- krysa rodu rattus MeSH
- potkani inbrední LEW MeSH
- potkani Wistar MeSH
- thioacetamid aplikace a dávkování toxicita MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
