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1.
Xenobiotica ; : 1-12, 2024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-39279675

RESUMO

Isolated perfused rat liver (IPRL) experiments have been used to answer clearance-related questions, including evaluating the impact of pathological and physiological processes on hepatic clearance (CLH). However, to date, IPRL data has not been evaluated for in vivo CLH prediction accuracy.In addition to a detailed overview of available IPRL literature, we present an in-depth analysis of the performance of IPRL in CLH prediction.While the entire dataset poorly predicted CLH (GAFE = 3.2; 64% within 3-fold), IPRL conducted under optimal experimental conditions, such as in the presence of plasma proteins and with a perfusion rate within 2-fold of physiological liver blood flow and corrected for unbound fraction in the presence of red blood cells, can accurately predict rat CLH (GAFE = 2.0; 78% within 3-fold). Careful consideration of experimental conditions is needed to allow proper data analysis.Further, isolated perfused liver experiments in other species, including human livers, may allow us to address the current in vitro-in vivo disconnects of hepatic metabolic clearance and improve our methodology for CLH predictions.

2.
Regul Toxicol Pharmacol ; : 105709, 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39343352

RESUMO

Accurately determining the mutagenicity of small-molecule N-nitrosamine drug impurities and nitrosamine drug substance-related impurities (NDSRIs) is critical to identifying mutagenic and cancer hazards. In the current study we have evaluated several approaches for enhancing assay sensitivity for evaluating the mutagenicity of N-nitrosamines in the bacterial reverse mutagenicity (Ames) test. Preincubation assays were conducted using five activation conditions: no exogenous metabolic activation and metabolic activation mixes employing both 10% and 30% liver S9 from hamsters and rats pretreated with inducers of enzymatic activity. In addition, preincubations were conducted for both 60 minutes and 30 minutes. These test variables were evaluated by testing 12 small-molecule N-nitrosamines and 17 NDSRIs for mutagenicity in Salmonella typhimurium tester strains TA98, TA100, TA1535, and TA1537, and Escherichia coli strain WP2 uvrA (pKM101). Eighteen of the 29 N-nitrosamine test substances tested positive under one or more of the testing conditions and all 18 positives could be detected by using tester strains TA1535 and WP2 uvrA (pKM101), preincubations of 30 minutes, and S9 mixes containing 30% hamster liver S9. In general, the conditions under which NDSRIs were mutagenic were similar to those found for small-molecule N-nitrosamines.

3.
Int J Mol Sci ; 25(2)2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38256179

RESUMO

Oxidative stress is involved in a wide range of age-related diseases. A critical role has been proposed for mitochondrial oxidative stress in initiating or promoting these pathologies and the potential for mitochondria-targeted antioxidants to fight them, making their search and testing a very urgent task. In this study, the mitochondria-targeted antioxidants SkQ1, SkQ3 and MitoQ were examined as they affected isolated rat liver mitochondria and yeast cells, comparing SkQ3 with clinically tested SkQ1 and MitoQ. At low concentrations, all three substances stimulated the oxidation of respiratory substrates in state 4 respiration (no ADP addition); at higher concentrations, they inhibited the ADP-triggered state 3 respiration and the uncoupled state, depolarized the inner mitochondrial membrane, contributed to the opening of the mPTP (mitochondrial permeability transition pore), did not specifically affect ATP synthase, and had a pronounced antioxidant effect. SkQ3 was the most active antioxidant, not possessing, unlike SkQ1 or MitoQ, prooxidant activity with increasing concentrations. In yeast cells, all three substances reduced prooxidant-induced intracellular oxidative stress and cell death and prevented and reversed mitochondrial fragmentation, with SkQ3 being the most efficient. These data allow us to consider SkQ3 as a promising potential therapeutic agent to mitigate pathologies associated with oxidative stress.


Assuntos
Mitocôndrias Hepáticas , Saccharomyces cerevisiae , Animais , Ratos , Antioxidantes/farmacologia , Mitocôndrias , Membranas Mitocondriais , Espécies Reativas de Oxigênio
4.
Pharm Res ; 40(11): 2513-2523, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37349653

RESUMO

BACKGROUND: Understanding the impact of altered hepatic uptake and/or efflux on the hepatobiliary disposition of the imaging agents [99mTc]Mebrofenin (MEB) and [153Gd]Gadobenate dimeglumine (BOPTA) is important for proper estimation of liver function. METHODS: A multi-compartmental pharmacokinetic (PK) model describing MEB and BOPTA disposition in isolated perfused rat livers (IPRLs) was developed. The PK model was simultaneously fit to MEB and BOPTA concentration-time data in the extracellular space, hepatocytes, bile canaliculi, and sinusoidal efflux in livers from healthy rats, and to BOPTA concentration-time data in rats pretreated with monocrotaline (MCT). RESULTS: The model adequately described MEB and BOPTA disposition in each compartment. The hepatocyte uptake clearance was much higher for MEB (55.3 mL/min) than BOPTA (6.67 mL/min), whereas the sinusoidal efflux clearance for MEB (0.000831 mL/min) was lower than BOPTA (0.0127 mL/min). The clearance from hepatocytes to bile (CLbc) for MEB (0.658 mL/min) was similar to BOPTA (0.642 mL/min) in healthy rat livers. The BOPTA CLbc was reduced in livers from MCT-pretreated rats (0.496 mL/min), while the sinusoidal efflux clearance was increased (0.0644 mL/min). CONCLUSION: A PK model developed to characterize MEB and BOPTA disposition in IPRLs was used to quantify changes in the hepatobiliary disposition of BOPTA caused by MCT pretreatment of rats to induce liver toxicity. This PK model could be applied to simulate changes in the hepatobiliary disposition of these imaging agents in rats in response to altered hepatocyte uptake or efflux associated with disease, toxicity, or drug-drug interactions.


Assuntos
Fígado , Compostos Organometálicos , Ratos , Animais , Fígado/diagnóstico por imagem , Fígado/metabolismo , Hepatócitos , Compostos Organometálicos/farmacocinética , Bile , Transporte Biológico
5.
J Peripher Nerv Syst ; 28(1): 98-107, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36371610

RESUMO

To contribute to the knowledge of the autonomic innervation in liver regeneration, here we investigate the distribution of tyrosine hydroxylase (TH)- and choline acetyltransferase (ChAT)-like immunoreactive (LI) nerve fibers, to indicate noradrenergic and cholinergic nerves, respectively, in rats under different conditions of liver damage and repair. By immunohistochemistry and assessment of nerve fiber density, three models of induced hepatic regeneration were examined: the carbon tetrachloride (CCl4 ) intoxication, with two treatment periods of 14 weeks and 18 weeks; the partial hepatectomy (PH); the thyroid hormone (T3) treatment. TH- and ChAT-LI nerve fibers were detectable mostly in the portal spaces, the TH-LI ones occurring only around blood vessels while the ChAT-LI nerve fibers were also associated with secretory ducts. The density of TH-like immunoreactivity in the portal areas decreased after the CCl4 14 weeks treatment and PH and increased after T3. By contrast, ChAT-LI nerve fibers appeared particularly abundant around the neoductal elements in the CCl4 rats and were rare to absent in the PH and T3-treated groups. The ChAT-LI nerve fiber density within the portal areas revealed an increase in the CCl4 -treated rats while showing no change in the PH and T3-treated rats. The changes in the density of perivascular TH- and ChAT-containing nerve fibers suggest a finely tuned autonomic modulation of hepatic blood flow depending on the type of subacute/chronic induced hyperplasia, while the characteristic occurrence of the periductal cholinergic innervation after the CCl4 treatment implies a selective parasympathetic role in regulating the physiopathological regenerative potential of the rat liver.


Assuntos
Fibras Nervosas , Ratos , Animais , Hiperplasia , Imuno-Histoquímica
6.
J Biochem Mol Toxicol ; 37(10): e23443, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37365769

RESUMO

The study aimed to investigate the hepatoprotective effects of purinergic receptor (P2X7R) antagonism by A438079 in liver damage. An experimental model of inflammation was performed by intraperitoneal (i.p.) lipopolysaccharide (LPS) administration in the rat. The groups were Control, A438079, dimethyl sulfoxide (DMSO), LPS, LPS + DMSO, and LPS + A438079. Following LPS (8 mg/kg) injection, A438079 (15 mg/kg) and DMSO (0.1 mL) were administrated (i.p) in the study groups. The blood and the liver tissues were removed for histological, biochemical, and western blot analyses. In the biochemical analysis, serum aspartate transaminase (AST) and alanine transaminase (ALT) concentrations, the tissue glutathione (GSH) level, and superoxide dismutase (SOD) activity dramatically decreased and malondialdehyde (MDA) level increased in the LPS and LPS + DMSO groups compared to the LPS + A438079 group. In the histological analysis, severe sinusoidal dilatation, necrotic hepatocytes, and inflammatory cell infiltration were observed in the LPS and LPS + DMSO groups while these effects were lessened in the LPS + A438079 group. The relative protein expression levels of P2X7R, Nf-kB-p65, IL-6, and Caspase-3 were significantly higher in the LPS and the LPS + DMSO groups than in the LPS + A438079 group. On the other hand, these protein expressions were considerably lower in the Control, A438079, and DMSO groups compared to the LPS + A438079 group. In addition, Bcl-2 protein expression was significantly lower in the LPS and the LPS + DMSO groups and higher in the LPS + A438079 group compared to the other groups. The protective effect of A438079 against LPS-induced hepatic inflammation may be related to P2X7R antagonism, inflammatory mediators, and apoptotic cell death.


Assuntos
Doença Hepática Crônica Induzida por Substâncias e Drogas , Lipopolissacarídeos , Ratos , Animais , Lipopolissacarídeos/toxicidade , Receptores Purinérgicos P2X7/metabolismo , Dimetil Sulfóxido/metabolismo , Dimetil Sulfóxido/farmacologia , Doença Hepática Crônica Induzida por Substâncias e Drogas/metabolismo , Doença Hepática Crônica Induzida por Substâncias e Drogas/patologia , Fígado/metabolismo , Inflamação/metabolismo , Alanina Transaminase
7.
Eur Surg Res ; 64(2): 310-314, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36380647

RESUMO

Although rat liver transplantation (LT) is useful in training surgeons to perform microsurgery, mastering these surgical techniques remains difficult. Systematized training protocols that enable learning of the proper skills in a short period of time are needed. The present study describes an efficient five-step rat LT training protocol for surgeons designed to be mastered within 3 months through continuous training. The first step was to review all procedures by watching full videos of rat LT and to watch actual LT operations performed by a skilled surgeon, enabling recognition of the anatomy of rat abdominal organs. The second step was to perform ten donor operations, including ex vivo graft preparation, to learn the atraumatic and delicate techniques. The third step was to perform ten LTs, with the goal of achieving an anhepatic time <20 min and surviving until the next day. The fourth step was to perform ten additional LTs, with the goal of achieving 7 days of survival. The fifth step was to perform 5-10 more LTs, with the goal of achieving 7 days of survival in five consecutive LT operations. Systematizing the training was found to increase its efficiency. Furthermore, determining the specific number of operations in advance is useful to maintain motivation for training. Mastering efficient rat LT will not only enhance the success of preclinical research but will enable young surgeons to better perform vascular anastomoses under a microscope in humans.


Assuntos
Transplante de Fígado , Cirurgiões , Humanos , Ratos , Animais , Transplante de Fígado/educação , Transplante de Fígado/métodos , Anastomose Cirúrgica/métodos , Cirurgiões/educação , Microcirurgia/educação
8.
Ecotoxicol Environ Saf ; 256: 114829, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36989557

RESUMO

Heavy metals are ubiquitous environmental pollutants that are extremely dangerous for public health, but the molecular mechanisms of their cytotoxic action are still not fully understood. In the present work, the possible contribution of the mitochondrial ATP-sensitive potassium channel (mK(ATP)), which is usually considered protective for the cell, to hepatotoxicity caused by heavy metals was investigated using polarography and swelling techniques as well as flow cytometry. Using isolated liver mitochondria from adult male Wistar rats and various potassium media containing or not containing penetrating anions (KNO3, KSCN, KAcet, KCl), we studied the effect of mK(ATP) modulators, namely its blockers (5-hydroxydecanoate, glibenclamide, ATP, ADP) and activators (diazoxide, malonate), on respiration and/or membrane permeability in the presence of hepatotoxins such as Cd2+, Hg2+, and Cu2+. It has been shown for the first time that, contrary to Hg2+ and depending on media used, the mK(ATP) modulators affect Cd2+- and/or Cu2+-induced alterations in mitochondrial swelling and respiration rates, although differently, nevertheless, in the ways compatible with mK(ATP) participation in both these cases. On rat AS-30D ascites hepatoma cells, it was found that, unlike Cd2+, an increase in the production of reactive oxygen species was observed with the simultaneous use of Cu2+ and diazoxide; in addition, there was no protective effect of diazoxide against cell death, which also occurred in the presence of Cu2+. In conclusion, the relationships (functional, structural and/or regulatory) between mK(ATP), components of the mitochondrial electron transport chain (CI, CII-CIII and/or ATP synthase, CV) and mitochondrial permeability transition pores were discussed, as well as the role of these molecular structures in the mechanisms of the cytotoxic action of heavy metals.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Mercúrio , Metais Pesados , Ratos , Masculino , Animais , Mitocôndrias Hepáticas , Canais KATP/metabolismo , Canais KATP/farmacologia , Diazóxido/metabolismo , Diazóxido/farmacologia , Cádmio/toxicidade , Ascite/metabolismo , Carcinoma Hepatocelular/metabolismo , Ratos Wistar , Metais Pesados/metabolismo , Mercúrio/metabolismo , Neoplasias Hepáticas/metabolismo , Trifosfato de Adenosina/metabolismo
9.
Int J Mol Sci ; 24(23)2023 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-38069169

RESUMO

Our previous animal studies found that the preventive effects of lactoferrin (Lf) on alcoholic liver injury (ALI) are associated with nuclear factor E2-related factor 2 (Nrf2). To further explore the causality, experiments were performed using rat normal liver BRL-3A cells. Lf treatment reduced ethanol-induced death and apoptosis; meanwhile, Lf treatment alleviated excessive LDH release. These findings confirmed the protection of Lf against ethanol-induced injury in BRL-3A cells. Mechanistically, Lf treatment reversed the reduction in nuclear Nrf2 induced by ethanol without affecting the cytoplasmic Nrf2 level, which led to antioxidant enzyme activity restoration. However, the blocking of Nrf2 nuclear translocation by ML385 eliminated the protective effects of Lf. In a conclusion, Lf protects BRL-3A cells from ethanol-induced injury via promoting Nrf2 nuclear translocation.


Assuntos
Etanol , Lactoferrina , Ratos , Animais , Etanol/toxicidade , Etanol/metabolismo , Lactoferrina/farmacologia , Lactoferrina/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Linhagem Celular , Fígado/metabolismo , Antioxidantes/farmacologia , Estresse Oxidativo
10.
Chirality ; 34(1): 126-133, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34736290

RESUMO

An efficient, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) chiral analysis method was established for determination of chloroquine and hydroxychloroquine enantiomers in rat liver microsomes. Effects of polysaccharide chiral stationary phases and basic additives on chiral separations of two analytes were discussed in detail. Amylose tris(3, 5-dimethylphenylcarbamate)-coated chiral stationary phase showed the best separation performance for them with acetonitrile-diethylamine-ethanol-diethylamine mixture (90:0.1:10:0.1, v/v/v/v) among four chiral stationary phases. Then, multiple reaction monitoring mode was selected as the data acquisition for determination of two pairs of enantiomers. The proposed LC-MS/MS chiral analysis method was validated in terms of linearity, accuracy, precision, and specificity. Good linearity with correlation coefficient over 0.998 was obtained in the concentration range of 0.05-5 µM. Limits of quantification for chloroquine and hydroxychloroquine enantiomers were 5.0 and 1.0 nM, respectively. The recoveries ranged from 81.14% to 111.09%. The intra-day and inter-day relative standard deviation were less than 6.5%. Moreover, concentrations of chloroquine and hydroxychloroquine enantiomers in rat liver microsomes were determined through the proposed LC-MS/MS analysis method. After incubated with rat liver microsomes for 10 min, the enantiomeric factor of hydroxychloroquine decreased from 0.50 to 0.45 (p < 0.001). In brief, our developed determination method for chloroquine and hydroxychloroquine enantiomers through LC-MS/MS spectrometry showed the characteristics of high-efficiency, fast speed, and very low detection limit, and would be greatly beneficial for screening and quantitation of them in biological matrices.


Assuntos
Hidroxicloroquina , Espectrometria de Massas em Tandem , Animais , Cloroquina , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Microssomos Hepáticos , Ratos , Estereoisomerismo
11.
Int J Mol Sci ; 23(16)2022 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-36012228

RESUMO

Recent data have shown that the mitochondrial permeability transition pore (MPTP) is the complex of the Ca2+-modified adenine nucleotide translocase (ANT) and the Ca2+-modified ATP synthase. We found in a previous study that ANT conformational changes may be involved in Tl+-induced MPTP opening in the inner membrane of Ca2+-loaded rat liver mitochondria. In this study, the effects of thiol-modifying agents (eosin-5-maleimide (EMA), fluorescein isothiocyanate (FITC), Cu(o-phenanthroline)2 (Cu(OP)2), and embelin (Emb)), and MPTP inhibitors (ADP, cyclosporine A (CsA), n-ethylmaleimide (NEM), and trifluoperazine (TFP)) on MPTP opening were tested simultaneously with increases in swelling, membrane potential (ΔΨmito) decline, decreases in state 3, 4, and 3UDNP (2,4-dinitrophenol-uncoupled) respiration, and changes in the inner membrane free thiol group content. The effects of these thiol-modifying agents on the studied mitochondrial characteristics were multidirectional and showed a clear dependence on their concentration. This research suggests that Tl+-induced MPTP opening in the inner membrane of calcium-loaded mitochondria may be caused by the interaction of used reagents (EMA, FITC, Emb, Cu(OP)2) with active groups of ANT, the mitochondrial phosphate carrier (PiC) and the mitochondrial respiratory chain complexes. This study provides further insight into the causes of thallium toxicity and may be useful in the development of new treatments for thallium poisoning.


Assuntos
Mitocôndrias Hepáticas , Proteínas de Transporte da Membrana Mitocondrial , Reagentes de Sulfidrila , Tálio , Animais , Cálcio/metabolismo , Fluoresceína-5-Isotiocianato/metabolismo , Fígado , Mitocôndrias Hepáticas/efeitos dos fármacos , Mitocôndrias Hepáticas/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Poro de Transição de Permeabilidade Mitocondrial , Ratos , Ratos Wistar , Compostos de Sulfidrila/metabolismo , Reagentes de Sulfidrila/farmacologia , Tálio/farmacologia
12.
Molecules ; 27(7)2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35408639

RESUMO

The role of individual cytochrome P450 (CYPs) responsible for the drug metabolism can be determined through their chemical inhibition. During the pandemic, dexamethasone and remdesivir with omeprazole were used for the treatment of COVID-19, while Ibuprofen was taken to treat the symptoms of fever and headache. This study aimed to examine the potency of ibuprofen remdesivir, and omeprazole as inhibitors of cytochrome P450s using rat liver microsomes in vitro. Dexamethasone a corticosteroid, sometimes used to reduce the body's immune response in the treatment of COVID-19, was used as a probe substrate and the three inhibitors were added to the incubation system at different concentrations and analysed by a validated High Performance Liquid Chromatography (HPLC) method. The CYP3A2 isoenzyme is responsible for dexamethasone metabolism in vitro. The results showed that ibuprofen acts as a non-competitive inhibitor for CYP3A2 activity with Ki = 224.981 ± 1.854 µM and IC50 = 230.552 ± 2.020 µM, although remdesivir showed a mixed inhibition pattern with a Ki = 22.504 ± 0.008 µM and IC50 = 45.007 ± 0.016 µM. Additionally, omeprazole uncompetitively inhibits dexamethasone metabolism by the CYP3A2 enzyme activity with a Ki = 39.175 ± 0.230 µM and IC50 = 78.351 ± 0.460 µM. These results suggest that the tested inhibitors would not exert a significant effect on the CYP3A2 isoenzyme responsible for the co-administered dexamethasone drug's metabolism in vivo.


Assuntos
Dexametasona , Ibuprofeno , Microssomos Hepáticos , Omeprazol , Monofosfato de Adenosina/análogos & derivados , Alanina/análogos & derivados , Animais , Citocromo P-450 CYP3A/metabolismo , Inibidores das Enzimas do Citocromo P-450/farmacologia , Sistema Enzimático do Citocromo P-450/metabolismo , Dexametasona/metabolismo , Dexametasona/farmacologia , Ibuprofeno/farmacologia , Isoenzimas/metabolismo , Masculino , Microssomos Hepáticos/metabolismo , Omeprazol/farmacologia , Ratos , Ratos Sprague-Dawley , Tratamento Farmacológico da COVID-19
13.
Med Mol Morphol ; 55(2): 100-109, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35048195

RESUMO

Both fascin and fibronectin are known to play important roles in cell adhesion and migration. They are noted as tumor markers or inhibiting target for tumor treatment. In this study, embryonic rat livers were obtained to examine the expression of fascin and fibronectin during liver development. Then, the effect of fibronectin on fascin expression was investigated. At embryonic day (ED) 10.5, when the foregut endoderm began to form the liver bud and spread into the septum transversum, fibrous extracellular matrix was observed between the space where the liver bud and the septum transversum merged. At ED11.5, fibronectin was observed surrounding the cluster of fascin-positive hepatoblasts. At ED13.5, hematopoietic cells emerged and both fibronectin and fascin expression started to decline. Fascin and fibronectin appeared temporarily and disappeared by ED 14.5. Their expression was chronologically synchronized. Subsequently, the effect of fibronectin on fascin was examined by cultivation of hepatoblasts that were isolated from the ED13.5 rat liver. As a result, with fibronectin, fascin was positive in most hepatoblasts, although, without fibronectin, fascin expression was remarkably declined. Presently, there are few studies about the relationship between fascin and fibronectin. Our findings suggest that fibronectin could regulate fascin expression in rat hepatoblasts.


Assuntos
Fibronectinas , Fígado , Animais , Proteínas de Transporte , Adesão Celular/fisiologia , Matriz Extracelular/metabolismo , Fibronectinas/metabolismo , Fígado/metabolismo , Proteínas dos Microfilamentos , Ratos
14.
Biometals ; 34(5): 987-1006, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34236558

RESUMO

The effects of both Tl+ and thiol reagents were studied on the content of the inner membrane free SH-groups, detected with Ellman reagent, and the inner membrane potential as well as swelling and respiration of succinate-energized rat liver mitochondria in medium containing TlNO3 and KNO3. These effects resulted in a rise in swelling and a decrease in the content, the potential, and mitochondrial respiration in 3 and 2,4-dinitrophenol-uncoupled states. A maximal effect was seen when phenylarsine oxide reacting with thiol groups recessed into the hydrophobic regions of the membrane. Compared with phenylarsine oxide, the effective concentrations of other reagents were approximately one order of magnitude higher in experiments with mersalyl and 4,4'-diisothiocyanostilbene-2,2'-disulfonate, and two orders of magnitude higher in experiments with tert-butyl hydroperoxide and diamide. The above effects of Tl+ and the thiol reagents became even more pronounced with calcium overload of mitochondria. However, the effects were suppressed by inhibitors of the mitochondrial permeability transition pore (cyclosporine A, ADP, and n-ethylmaleimide). These findings suggest that opening of the pore induced by Tl+ in the inner membrane can be dependent on the conformation state of the adenine nucleotide translocase, which depends on the activity of its thiol groups.


Assuntos
Mitocôndrias Hepáticas , Proteínas de Transporte da Membrana Mitocondrial , Animais , Cálcio/metabolismo , Potencial da Membrana Mitocondrial , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/farmacologia , Permeabilidade , Ratos , Ratos Wistar , Respiração , Ácido Succínico/metabolismo , Ácido Succínico/farmacologia , Compostos de Sulfidrila/metabolismo , Compostos de Sulfidrila/farmacologia , Reagentes de Sulfidrila/metabolismo , Reagentes de Sulfidrila/farmacologia , Tálio/metabolismo , Tálio/farmacologia
15.
Acta Pharmacol Sin ; 42(12): 2094-2105, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33686245

RESUMO

Aristolochic acid I (AAI) is a well-known nephrotoxic carcinogen, which is currently reported to be also associated with hepatocellular carcinoma (HCC). Whether AAI is a direct hepatocarcinogen remains controversial. In this study we investigated the association between AAI exposure and HCC in adult rats using a sensitive rat liver bioassay with several cofactors. Formation of glutathione S-transferase placental form-positive (GST-P+) foci was used as the marker for preneoplastic lesions/clonal expansion. We first conducted a medium-term (8 weeks) study to investigate whether AAI had any tumor-initiating or -promoting activity. Then a long-term (52 weeks) study was conducted to determine whether AAI can directly induce HCC. We showed that oral administration of single dose of AAI (20, 50, or 100 mg/kg) in combination with partial hepatectomy (PH) to stimulate liver proliferation did not induce typical GST-P+ foci in liver. In the 8-week study, only high dose of AAI (10 mg · kg-1 · d-1, 5 days a week for 6 weeks) in combination with PH significantly increased the number and area of GST-P+ foci initiated by diethylnitrosamine (DEN) in liver. Similarly, only high dose of AAI (10 mg· kg-1· d-1, 5 days a week for 52 weeks) in combination with PH significantly increased the number and area of hepatic GST-P+ foci in the 52-week study. No any nodules or HCC were observed in liver of any AAI-treated groups. In contrast, long-term administration of AAI (0.1, 1, 10 mg· kg-1· d-1) time- and dose-dependently caused death due to the occurrence of cancers in the forestomach, intestine, and/or kidney. Besides, AAI-DNA adducts accumulated in the forestomach, kidney, and liver in a time- and dose-dependent manner. Taken together, AAI promotes clonal expansion only in the high-dose group but did not induce any nodules or HCC in liver of adult rats till their deaths caused by cancers developed in the forestomach, intestine, and/or kidney. Findings from our animal studies will pave the way for further large-scale epidemiological investigation of the associations between AA and HCC.


Assuntos
Ácidos Aristolóquicos/toxicidade , Carcinógenos/toxicidade , Carcinoma Hepatocelular/etiologia , Hepatócitos/metabolismo , Neoplasias Hepáticas/etiologia , Mutagênicos/toxicidade , Animais , Carcinogênese/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Adutos de DNA/efeitos dos fármacos , Glutationa S-Transferase pi/metabolismo , Neoplasias Intestinais/induzido quimicamente , Intestinos/patologia , Rim/patologia , Neoplasias Renais/induzido quimicamente , Fígado/metabolismo , Fígado/patologia , Masculino , Ratos Sprague-Dawley , Estômago/patologia , Neoplasias Gástricas/induzido quimicamente
16.
Gen Comp Endocrinol ; 302: 113661, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33220302

RESUMO

To test the hypothesis of conservation of stanniocalcin 1 and 2 (STC-1; STC-2) metabolic functions in vertebrates, we performed an in vitro study to determine if these hormones are implicated in regulation of the gluconeogenesis pathway, glycogen synthesis, and 14C-glucose conversion to 14CO2 in livers from fed and fasting rats (Rattus norvegicus). Stc1 and Stc2 gene expressions increased in the liver after fasting. STC-1 participated in the regulation of the hepatic gluconeogenesis pathway in rats when the precursor was 14C-lactate. STC-2 demonstrated variational signaling on rat hepatic gluconeogenesis activity and Pck1 gene expression, decreasing levels in the fed state when the substrate was 14C-alanine and increasing levels during fasting when the substrate was 14C-lactate. At the concentrations used in this study, STC-1 and STC-2 did not affect glycogen concentration and synthesis from 14C-glucose or 14C-glucose conversion to 14CO2 in the livers from fed or fasting rats. These findings highlight the role of stanniocalcins in the hepatic gluconeogenesis pathway in mammals and confirm the conservation of STC-1 and STC-2 metabolic functions in the vertebrates.


Assuntos
Jejum , Gluconeogênese , Animais , Glucose/metabolismo , Glicoproteínas , Homeostase , Hormônios/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Fígado/metabolismo , Ratos
17.
Ecotoxicol Environ Saf ; 212: 111968, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33550083

RESUMO

Despite the fact that copper (Cu) is a vital micronutrient to maintain body function, high doses of Cu through environmental exposure damage various organs, especially the liver, which is the main metabolic organ. To investigate the influence of long-term Cu-induced toxicity on mitophagy and apoptosis in rat liver, 96 seven-month-old male Sprague-Dawley rats were fed TBCC for 24 weeks. The results revealed that exposure to high Cu concentrations could promote oxidative stress liver injury by increasing the hepatic function index (ALT, AST and ALP) and MDA content, while reducing the activity of antioxidant enzymes (T-SOD, GSH-Px and CAT) related to oxidative stress. Consistent with histopathological observations, proper dietary Cu (15-60 mg/kg) could improve antioxidant stress levels and induce a dose-dependent increase in the mRNA expression of mitophagy-related genes, whereas a high Cu concentration (120 mg/kg) could cause severe liver impairment and ultrastructural changes and a reduction in mitophagosomes, accompanied by downregulation of Atg5, Beclin1, Pink1, Parkin, NIX, P62 and LC3B. The expression of apoptosis-related genes (Bax, Bax/Bcl-2, Caspase3, Cytc and p53) and proteins (Caspase3 and p53) was upregulated with the addition of dietary Cu. The results demonstrated that an appropriate dose of TBCC could improve liver function by promoting mitophagy and Cu enzymes that play antioxidative roles, while the accumulation of excess Cu could induce liver lesions by enhancing apoptosis and inhibiting mitophagy pathways.


Assuntos
Cloretos/toxicidade , Cobre/toxicidade , Animais , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Sulfato de Cobre/análise , Dieta , Fígado/metabolismo , Masculino , Mitofagia/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Testes de Toxicidade Crônica
18.
Pestic Biochem Physiol ; 178: 104938, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34446205

RESUMO

The adverse effects of chlorpyrifos, cypermethrin, and imidacloprid on mitochondrial dysfunction and oxidative stress biomarkers were studied in rat liver. The liver deficiency was also confirmed by histological analysis and gel electrophoresis. Each insecticide was administered orally with five doses per week for 28 days to male albino rats at 1/50 of the LD50 per insecticide. The results demonstrated that the mitochondrial dysfunction was confirmed by a significant decrease in NADH dehydrogenase and ATPase activities. Oxidative stress biomarkers include malondialdehyde (MDA), and protein carbonyl content (PCC) were significantly increased. However, superoxide dismutase (SOD) and glutathione S-transferase (GST) as antioxidant enzymes were significantly decreased in the mitochondria of the rat liver. HPLC analysis showed a significant increase of the 8-hydroxy-2'-deoxyguanosine (8-OH-2DG) as a biomarker of the DNA damage in rat liver. In addition, the residue levels of 0.96 and 0.29 µg/mL serum were found for cypermethrin and imidacloprid, respectively. However, chlorpyrifos not detected using the HPLC analysis. Blue native polyacrylamide gel electrophoresis (BN-PAGE) analysis showed a change in the pattern and sequence of complexions of the electron transport chain in liver mitochondria with treatment by such insecticides. The hepatic histological examination also showed symptoms of abnormalities after exposure to these insecticides.


Assuntos
Clorpirifos , Inseticidas , Animais , Antioxidantes/metabolismo , Clorpirifos/metabolismo , Clorpirifos/toxicidade , Inseticidas/metabolismo , Inseticidas/toxicidade , Fígado/metabolismo , Mitocôndrias , Neonicotinoides , Nitrocompostos , Estresse Oxidativo , Carbonilação Proteica , Piretrinas , Ratos
19.
Pestic Biochem Physiol ; 179: 104964, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34802514

RESUMO

In this work, stereochemistry of uniconazole enantiomers and their metabolism behaviors in rat liver microsomes have been researched. Significance analysis has been applied in data processing. Absolute configurations of uniconazole enantiomers were identified through vibrational circular dichroism spectroscopy. According to their elution order from the chiral column using the CO2-methanol (80:20, v/v) mixture, two eluted fractions were determined to be (R)-uniconazole and (S)-uniconazole, respectively. A high-efficient and sensitive LC-MS/MS chiral analysis method was established for investigating the metabolism of uniconazole enantiomers in rat liver microsomes. The metabolic half-life of (R)-uniconazole (38.7 min) in rat liver microsomes was half that of (S)-enantiomer (74.5 min), and maximum velocity of metabolism, Michaelis constant of metabolism as well as the intrinsic metabolic clearance of (R)-uniconazole were significantly higher than (S)-enantiomer (p < 0.05), which indicated that (R)-uniconazole was preferentially metabolized in rat liver microsomes. By the virtue of molecular docking, (R)-uniconazole exhibited a higher binding affinity to cytochrome CYP2D2 than (S)-enantiomer, which corroborated well with the metabolism results. This work will shed light on the risk assessment of uniconazole toward human health and the ecological environment.


Assuntos
Microssomos Hepáticos , Praguicidas , Animais , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Simulação de Acoplamento Molecular , Ratos , Estereoisomerismo , Espectrometria de Massas em Tandem , Triazóis
20.
Int J Mol Sci ; 22(16)2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34445153

RESUMO

In order to achieve a desired therapeutic effect in schizophrenia patients and to maintain their mental wellbeing, pharmacological therapy needs to be continued for a long time, usually from the onset of symptoms and for the rest of the patients' lives. The aim of our present research is to find out the in vivo effect of chronic treatment with atypical neuroleptic iloperidone on the expression and activity of cytochrome P450 (CYP) in rat liver. Male Wistar rats received a once-daily intraperitoneal injection of iloperidone (1 mg/kg) for a period of two weeks. Twenty-four hours after the last dose, livers were excised to study cytochrome P450 expression (mRNA and protein) and activity, pituitaries were isolated to determine growth hormone-releasing hormone (GHRH), and blood was collected for measuring serum concentrations of hormones and interleukin. The results showed a broad spectrum of changes in the expression and activity of liver CYP enzymes, which are important for drug metabolism (CYP1A, CYP2B, CYP2C, and CYP3A) and xenobiotic toxicity (CYP2E1). Iloperidone decreased the expression and activity of CYP1A2, CP2B1/2, CYP2C11, and CYP3A1/2 enzymes but increased that of CYP2E1. The CYP2C6 enzyme remained unchanged. At the same time, the level of GHRH, GH, and corticosterone decreased while that of T3 increased, with no changes in IL-2 and IL-6. The presented results indicate neuroendocrine regulation of the investigated CYP enzymes during chronic iloperidone treatment and suggest a possibility of pharmacokinetic/metabolic interactions produced by the neuroleptic during prolonged combined treatment with drugs that are substrates of iloperidone-affected CYP enzymes.


Assuntos
Antipsicóticos/farmacologia , Sistema Enzimático do Citocromo P-450/metabolismo , Isoxazóis/farmacologia , Fígado/efeitos dos fármacos , Piperidinas/farmacologia , Animais , Antipsicóticos/administração & dosagem , Sistema Enzimático do Citocromo P-450/genética , Expressão Gênica/efeitos dos fármacos , Isoxazóis/administração & dosagem , Fígado/metabolismo , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Piperidinas/administração & dosagem , Ratos , Ratos Wistar , Esquizofrenia/tratamento farmacológico , Esquizofrenia/metabolismo
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