Rapid liver self-recovery: A challenge for rat models of tissue damage.

Animal models, mainly murine, stay as a fundamental resource in diverse research pursuits, notably contributing to significant strides in discovering novel treatments for therapeutic applications. Preclinical assays must consider the existence of self-recovery mechanisms in the murine species to achieve a well-designed control group. This study focuses on unveiling the innate rapid regenerative capacity of rat liver by utilizing the thioacetamide-induced sub-chronic liver injury model. Employing histopathological, biochemical, and molecular liver function tests, we assessed the recovery of liver tissue functionality. Moreover, animals were housed with voluntary running wheels and locomotory activity was recorded and employed as an indirect index of overall animal recuperation. Remarkably, basal locomotory activity reestablished to normal levels only two weeks post-thioacetamide exposure. Our results raise vital considerations about the importance of temporal synchronicity in comparative assays to validate the real action of treatments, emphasizing the role of the rapid rat liver endogenous self-recovery.

Effective Inhibition of TNFalpha/mTOR Axis-Mediated Liver Inflammation and Fibrosis Induced by TAA Using a Combination of Metformin and Resveratrol in Association with the Inhibition of the Profibrotic Gene and Protein Expression / Inhibición Efectiva de la Inflamación Hepática Mediada por el Eje TNF-alfa/mTOR y la Fibrosis Inducida por TAA Utilizando una Combinación de Metformina y Resveratrol en Asociación con la Inhibición del Gen Profibrótico y la Expresión de Proteínas

SUMMARY: The response of the immune system to harmful stimuli leads to inflammation, and the adverse effects of the toxic hepatitis chemical, thioacetamide (TAA) on the human body are well documented. This article investigated the degree of protection provided by the combined pleotropic drug, metformin (Met) and the plant polyphenolic and the antiinflammatory compound, resveratrol (Res) on liver tissue exposed to TAA possibly via the inhibition of the inflammatory cytokine, tumor necrosis factor-α (TNF-α) / mammalian target of rapamycin (mTOR) axis-mediated liver fibrosis, as well as amelioration of profibrotic gene and protein expression. Rats were either given TAA (200 mg/kg via intraperitoneal injection) for 8 weeks beginning at the third week (experimental group) or received during the first two weeks of the experiment combined doses of metformin (200 mg/kg) and resveratrol (20 mg/kg) and continued receiving these agents and TAA until experiment completion at week 10 (treated group). A considerable damage to hepatic tissue in the experimental rats was observed as revealed by tissue collagen deposition in the portal area of the liver and a substantial increase (p<0.0001) in hepatic levels of the inflammatory marker, tumor necrosis factor-α (TNF-α), as well as blood levels of hepatocellular injury biomarkers, alanine aminotransferase (ALT) and aspartate aminotransferase (AST). TAA also augmented hepatic tissue levels of the signalling molecule that promotes liver fibrosis (mTOR), and profibrogenic markers; alpha-smooth muscle actin (α-SMA) protein, tissue inhibitor of metalloproteinases-1 (TIMP-1) mRNA, and matrix metalloproteinase-9 (MMP-9) mRNA. All these parameters were protected (p≤0.0016) by Met+Res. In addition, a significant correlation was detected between liver fibrosis score and inflammation, liver injury enzymes, mTOR, and profibrogenesis markers. Thus, these findings suggest that Met+Res effectively protect the liver against damage induced by thioacetamide in association with the downregulation of the TNF-α/mTOR/fibrosis axis.

La respuesta del sistema inmunológico a estímulos dañinos conduce a la inflamación y los efectos adversos de la tioacetamida (TAA), una sustancia química tóxica para el hígado, están bien documentadas. Este artículo investigó el grado de protección proporcionado por el fármaco pleotrópico combinado metformina (Met), el polifenólico vegetal y el compuesto antiinflamatorio resveratrol (Res) en el tejido hepático expuesto a TAA, posiblemente a través de la inhibición de la citoquina inflamatoria, factor de necrosis tumoral α (TNF-α)/objetivo de la fibrosis hepática mediada por el eje de rapamicina (mTOR), así como mejora de la expresión de genes y proteínas profibróticas. Las ratas recibieron TAA (200 mg/kg mediante inyección intraperitoneal) durante 8 semanas a partir de la tercera semana (grupo experimental) o recibieron durante las dos primeras semanas del experimento dosis combinadas de metformina (200 mg/kg) y resveratrol (20 mg/kg) y continuaron recibiendo estos agentes y TAA hasta completar el experimento en la semana 10 (grupo tratado). Se observó un daño considerable al tejido hepático en las ratas experimentales, como lo revela el depósito de colágeno tisular en el área portal del hígado y un aumento sustancial (p<0,0001) en los niveles hepáticos del marcador inflamatorio, el factor de necrosis tumoral-α (TNF- α), así como los niveles sanguíneos de biomarcadores de lesión hepatocelular, alanina aminotransferasa (ALT) y aspartato aminotransferasa (AST). TAA también aumentó los niveles en el tejido hepático de la molécula de señalización que promueve la fibrosis hepática (mTOR) y marcadores profibrogénicos; proteína actina del músculo liso alfa (α- SMA), inhibidor tisular de las metaloproteinasas-1 (TIMP-1) mRNA y matriz metaloproteinasa-9 (MMP-9) mRNA. Todos estos parámetros fueron protegidos (p≤0.0016) por Met+Res. Además, se detectó una correlación significativa entre la puntuación de fibrosis hepática y la inflamación, las enzimas de lesión hepática, mTOR y los marcadores de profibrogénesis. Por lo tanto, estos hallazgos sugieren que Met+Res protege eficazmente el hígado contra el daño inducido por la tioacetamida en asociación con la regulación negativa del eje TNF-α/mTOR/fibrosis.

Metformin Inhibits ROS/TNF-alpha Axis-Mediated Chronic Kidney Disease Induced by TAA Independent of Leukocyte Infiltration in Association with the Inhibition of Kidney Injury Biomarkers / La Metformina Inhibe la Enfermedad Renal Crónica Mediada por el Eje ROS/TNF-alfa Inducida por TAA Independientemente de la Infiltración de Leucocitos en Asociación con la Inhibición de Biomarcadores de Lesión Renal

SUMMARY: The toxic effects of thioacetamide (TAA) and carbon tetrachloride on the human body are well recognized. In this study, we examined whether TAA intoxication can induce kidney leukocyte infiltration (measured as leukocyte common antigen CD45) associated with the augmentation of the reactive oxygen species (ROS)/tumor necrosis factor-alpha (TNF-α) axis, as well as biomarkers of kidney injury with and without metformin treatment. Rats were either injected with TAA (200 mg/kg; twice a week for 8 weeks) before being sacrificed after 10 weeks (experimental group) or were pre-treated with metformin (200 mg/kg) daily for two weeks prior to TAA injections and continued receiving both agents until the end of the experiment, at week 10 (protective group). Using basic histology staining, immunohistochemistry methods, and blood chemistry analysis, we observed profound kidney tissue injury such as glomerular and tubular damage in the experimental group, which were substantially ameliorated by metformin. Metformin also significantly (p0.05) increase in kidney expression of CD45 positive immunostaining cells. In conclusion, we found that TAA induces kidney injury in association with the augmentation of ROS/TNF-α axis, independent of leukocyte infiltration, which is protected by metformin.

Son bien conocidosos los efectos tóxicos de la tioacetamida (TAA) y el tetracloruro de carbono en el cuerpo humano. En este estudio, examinamos si la intoxicación por TAA puede inducir la infiltración de leucocitos renales (medida como antígeno leucocitario común CD45) asociada con el aumento de las especies reactivas de oxígeno (ROS)/factor de necrosis tumoral-alfa (TNF-α), así como biomarcadores de daño renal con y sin tratamiento con metformina. A las ratas se les inyectó TAA (200 mg/kg; dos veces por semana durante 8 semanas) antes de sacrificarlas a las 10 semanas (grupo experimental) o se les pretrató con metformina (200 mg/kg) diariamente durante dos semanas antes de las inyecciones de TAA y continuaron recibiendo ambos agentes hasta el final del experimento, en la semana 10 (grupo protector). Usando tinción histológica básica, métodos de inmunohistoquímica y análisis químico de la sangre, observamos una lesión profunda del tejido renal, como daño glomerular y tubular en el grupo experimental, que mejoraron sustancialmente con la metformina. La metformina también inhibió significativamente (p0,05) en la expresión renal de células de inmunotinción positivas para CD45. En conclusión, encontramos que el TAA induce la lesión renal en asociación con el aumento del eje ROS/TNF-α, independientemente de la infiltración de leucocitos, que está protegida por metformina.

Captopril inhibits thioacetamide-induced chronic liver injury associated with the suppression of inflammation / hypoxia- inducible factor 1-alpha / profibrogenic axis-mediated hepatotoxicity in rats / Captopril inhibe la lesión hepática crónica inducida por tioacetamida asociada con la supresión de la inflamación/factor 1-alfa inducible por hipoxia/hepatotoxicidad mediada por el eje profibrogénico en rata

SUMMARY: Liver transplantation is the only available method to treat liver failure induced by chronic liver injury. We sought to determine whether the angiotensin-converting enzyme inhibitor, captopril, can inhibit the development of chronic liver injury induced by the hepatotoxic agent thioacetamide (TAA) in association with the suppression of inflammation (hsCRP, TNF-α, and IL-6) / hypoxia- inducible factor 1-alpha (HIF-1α) / profibrosis (TIMP-1, MMP-9, and α-SMA) axis that mediates liver injury. Therefore, the model group of rats was injected for eight weeks with 200 mg/kg TAA starting at week two. The protective group was pretreated with 150 mg/ kg captopril daily for two weeks prior to TAA injections and continued receiving both capropril and TAA agents until being humanely scrificed at week 10. We observed a substantial damage to liver tissue in the model group as demonstrated by a significant (p<0.0001) increase in blood and hepatic tissue levels of high sensitivity C-reactive protein (hsCRP), tumor necrosis factor-a (TNF-α), interleukin- 6 (L-6), HIF-1α, tissue inhibitor of metalloproteinases-1 (TIMP-1), matrix metalloproteinase-9 (MMP-9), alpha-smooth muscle actin (α-SMA), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). All these parameters were significantly (p<0.0244) protected by captopril. Also, a significant (p<0.0001) positive correlation was observed between a-SMA (profibrosis) and the serum and tissue levels of hsCRP, TNF-α, HIF-1α, TIMP-1, MMP-9, and ALT. Thus, these findings suggest that the induction of chronic liver injury by the hepatotoxic compound, TAA is associated with the upregulation of inflammation/HIF-1α/profibrosis, with captopril exhibiting beneficial hepatic pleotropic effects.

El trasplante de hígado es el único método disponible para tratar la insuficiencia hepática inducida por una lesión hepática crónica. Buscamos determinar si el inhibidor de la enzima convertidora de angiotensina, captopril, puede inhibir el desarrollo de lesión hepática crónica inducida por el agente hepatotóxico tioacetamida (TAA) en asociación con la supresión de la inflamación (hsCRP, TNF-α e IL-6) / factor inducible por hipoxia 1-alfa (HIF-1α) / profibrosis (TIMP-1, MMP-9 y α- SMA) eje que media la lesión hepática. Por lo tanto, al grupo modelo de ratas se le inyectó durante ocho semanas 200 mg/kg de TAA a partir de la semana dos. El grupo protector fue pretratado con 150 mg/kg de captopril al día durante dos semanas antes de las inyecciones de TAA y continuó recibiendo capropril y agentes TAA hasta que fue sacrificado en la semana 10. Observamos un daño sustancial en el tejido hepático en el grupo modelo, como lo demuestra un aumento significativo (p<0,0001) de los niveles en sangre y tejido hepático de proteína C reactiva de alta sensibilidad (hsCRP), factor de necrosis tumoral-α (TNF-a), interleucina-6 (L-6), HIF-1α, inhibidor tisular de metaloproteinasas-1 (TIMP-1), metaloproteinasa de matriz-9 (MMP-9), actina de músculo liso alfa (α-SMA), alanina aminotransferasa (ALT) y aspartato aminotransferasa (AST). Todos estos parámetros estaban significativamente (p<0,0244) protegidos por captopril. Además, se observó una correlación positiva significativa (p<0,0001) entre α-SMA (profibrosis) y los niveles séricos y tisulares de hsCRP, TNF-α, HIF-1α, TIMP- 1, MMP-9 y ALT. Por lo tanto, estos hallazgos sugieren que la inducción de daño hepático crónico por el compuesto hepatotóxico, TAA, está asociada con la regulación al alza de la inflamación/HIF-1α/profibrosis, con captopril exhibiendo efectos pleotrópicos hepáticos beneficiosos.

The antioxidant and anti-inflammatory activities of caffeine effectively attenuate nonalcoholic steatohepatitis and thioacetamide-induced hepatic injury in male rats.

The antioxidant effect of caffeine, associated with its ability to upregulate the nuclear factor-E2-related factor-2 (Nrf2)-signaling pathway, was explored as a possible mechanism for the attenuation of liver damage. Nonalcoholic steatohepatitis (NASH) was induced in rats by the administration of a high-fat, high-sucrose, high-cholesterol diet (HFSCD) for 15 weeks. Liver damage was induced in rats by intraperitoneal administration of thioacetamide (TAA) for six weeks. Caffeine was administered orally at a daily dose of 50 mg/kg body weight during the period of NASH induction to evaluate its ability to prevent disease development. Meanwhile, rats received TAA for three weeks, after which 50 mg/kg caffeine was administered daily for three weeks with TAA to evaluate its capacity to interfere with the progression of hepatic injury. HFSCD administration induced hepatic steatosis, decreased Nrf2 levels, increased oxidative stress, induced the activation of nuclear factor-κB (NF-κB), and elevated proinflammatory cytokine levels, leading to hepatic damage. TAA administration produced similar effects, excluding steatosis. Caffeine increased Nrf2 levels; attenuated oxidative stress markers, including malondialdehyde and 4-hydroxynonenal; restored normal, reduced glutathione levels; and reduced NF-κB activation, inflammatory cytokine levels, and damage. Our findings suggest that caffeine may be useful in the treatment of human liver diseases.

Model of Liver Fibrosis Induction by Thioacetamide in Rats for Regenerative Therapy Studies.

Hepatic fibrosis is caused by chronic injury due to toxic, infectious, or metabolic causes, and it may progress to cirrhosis and hepatocellular carcinoma. There is currently no antifibrotic therapy authorized for human use; however, there are promising studies using cell therapies. There are also no animal models that exactly reproduce human liver fibrosis that can be used to better understand the mechanisms of its regression and identify new targets for treatment and therapeutic approaches. On the other hand, mesenchymal stem cells (MSC) have experimentally demonstrated fibrosis regression effects, but it is necessary to have an animal model of advanced liver fibrosis to evaluate the effect of these cells. The aim of this work was to establish a protocol for the induction of advanced liver fibrosis in rats using thioacetamide (TAA), which will allow us to perform trials using MSC as a possible therapy for fibrosis regression. For this purpose, we selected 24 female rats and grouped them into three experimental groups: the control group (G-I) without treatment and groups II (G-II) and III (G-III) that received TAA by intraperitoneal injection for 24 weeks. Then, 1 × 106/kg adipose mesenchymal stem cells (ASCs) were infused intravenously. Groups G-I and G-II were sacrificed 7 days after the last dose of ASC, and G-III was sacrificed 8 weeks after the last ASC infusion, all with xylazine/ketamine (40 mg/kg). The protocol used in this work established a model of advanced hepatic fibrosis as corroborated by METAVIR tests of the histological lesions; by the high levels of the markers α-SMA, CD68, and collagen type I; by functional alterations due to elevated markers of the hepatic lesions; and by alterations of the leukocytes, lymphocytes, and platelets. Finally, transplanted cells in the fibrous liver were detected. We conclude that TAA applied using the protocol introduced in this study induces a good model of advanced liver fibrosis in rats.

Modified Levels of Renin Angiotensin Related Components in the Frontal Cortex and Hippocampus were Associated with Neuroinflammation and Lower Neuroprotective Effects of NGF During Acute Hepatic Encephalopathy in Mice.

BACKGROUND: Hepatic encephalopathy (HE) is a neuropsychiatric syndrome that involves cognitive and motor dysfunctions due to hepatic failure. The clinical and experimental studies suggest that the angiotensin (Ang) converting enzyme (ACE), Ang II, and angiotensin type 1 receptor (AT1R), which compose the classical pathway of the renin-angiotensin system (RAS), exacerbate neuroinflammation in different neurologic diseases. Conversely, Ang-(1-7), ACE2, and Mas receptor, which integrate the alternative RAS axis, have been shown as promising therapeutic targets in neuropsychiatric disorders, leading to neuroprotection. OBJECTIVE: This study aimed to investigate the potential participation of the RAS components in thioacetamide (TAA)-induced HE in mice. METHODS: We also evaluated the levels of neurotrophic factors, pro-inflammatory cytokines, and chemokine in the central nervous system of TAA-induced HE in mice. Mice were submitted to acute liver failure induced by TAA administration by intraperitoneal route. Measurements of RAS components (ACE, Ang II, ACE2 and Ang1-7) and neurotrophic factors (BDNF, GDNF and NGF) were obtained by ELISA assay. Pro-inflammatory cytokines (TNF, IFN-γ, IL-6, IL-12p70) and the chemokine (CCL2) were quantified by cytometric bead array. The student's t-test was applied for statistical analysis. RESULTS: Mice presented increased cortical levels of ACE, while Ang-(1-7) levels were decreased in cortical and hippocampal samples compared to controls. Moreover, HE mice had an increase in the Ang II/Ang-(1-7) ratio along with reduced levels of neural growth factor (NGF) in the prefrontal cortex. They also showed elevated levels of IFN-γ and CCL2 in the prefrontal cortex and of TNF, IL-6, IL-12, and CCL2 in the hippocampus compared with controls. CONCLUSION: This study suggested that the reduction of components of the alternative RAS axis was associated with the deleterious effects of neuroinflammation and lower neuroprotective effects of NGF during TAA-induced HE.

Caffeine mitigates experimental nonalcoholic steatohepatitis and the progression of thioacetamide-induced liver fibrosis by blocking the MAPK and TGF-ß/Smad3 signaling pathways.

INTRODUCTION AND OBJECTIVES: Caffeine consumption is associated with beneficial effects on hepatic disorders. The objectives of this study were to evaluate the antifibrotic effects of caffeine on experimental nonalcoholic steatohepatitis (NASH) induced with a high-fat, high-sucrose, high-cholesterol diet (HFSCD), as well as to evaluate the ability of caffeine to prevent the progression of experimental liver fibrosis induced by the administration of thioacetamide (TAA) in rats and explore the mechanisms of action. METHODS: NASH and fibrosis were induced in rats by the administration of an HFSCD for 15 weeks, and liver fibrosis was induced by intraperitoneal administration of 200 mg/kg TAA 3 times per week, for 6 weeks. Caffeine was administered at a dose of 50 mg/kg body weight. The effects of diet, TAA, and caffeine on fibrosis were evaluated by biochemical and histological examinations. The profibrotic pathways were analyzed by western blotting and immunohistochemistry. RESULTS: Rats exhibited liver fibrosis after HFSCD feeding and the administration of TAA. Caffeine could reduce the hepatic level of collagen and the fibrotic area in the liver. Caffeine prevented the progression of liver fibrosis by decreasing transforming growth factor-beta (TGF-ß), connective tissue growth factor (CTGF), and alpha-smooth muscle actin (α-SMA) expression and by inhibiting the activation of mitogen-activated protein kinases (MAPKs) and Smad3 phosphorylation. CONCLUSIONS: Caffeine attenuates NASH and the progression of liver fibrosis due to its antifibrotic effects and modulating the MAPK and TGF-ß pathways. Therefore, caffeine could be a suitable candidate for treating liver diseases associated with fibrosis.

Vitamin D3 supplementation alleviates chemically-induced cirrhosis-associated hepatocarcinogenesis.

Vitamin D3 (VD3) deficiency has been associated with increased risk for cirrhosis and hepatocellular carcinoma, a highly incident malignant neoplasia worldwide. On the other hand, VD3 supplementation has shown some beneficial effects in clinical studies and rodent models of chronic liver disease. However, preventive effects of dietary VD3 supplementation in cirrhosis-associated hepatocarcinogenesis is still unknow. To investigate this purpose, male Wistar rats submitted to a combined diethylnitrosamine- and thioacetamide-induced model were concomitantly supplemented with VD3 (5,000 and 10,000 IU/kg diet) for 25 weeks. Liver samples were collected for histological, biochemical and molecular analysis. Serum samples were used to measure 25-hydroxyvitamin D [25(OH)D] and alanine aminotransferase levels. Both VD3 interventions decreased hepatic collagen deposition and pro-inflammatory p65 protein levels, while increased hepatic antioxidant catalase and glutathione peroxidase activities and serum 25(OH)D, without a clear dose-response effect. Nonetheless, only the highest concentration of VD3 increased hepatic protein levels of VD receptor, while decreased the number of large preneoplastic glutathione-S-transferase- (>0.5 mm²) and keratin 8/18-positive lesions, as well the multiplicity of hepatocellular adenomas. Moreover, this intervention increased hepatic antioxidant Nrf2 protein levels and glutathione-S-transferase activity. In summary, dietary VD3 supplementation - in special the highest intervention - showed antifibrotic and antineoplastic properties in chemically-induced cirrhosis-associated hepatocarcinogenesis. The positive modulation of Nrf2 antioxidant axis may be mechanistically involved with these beneficial effects, and may guide future clinical studies.

Acceleration of TAA-Induced Liver Fibrosis by Stress Exposure Is Associated with Upregulation of Nerve Growth Factor and Glycopattern Deviations.

Liver fibrosis results from many chronic injuries and may often progress to cirrhosis and hepatocellular carcinoma (HCC). In fact, up to 90% of HCC arise in a cirrhotic liver. Conversely, stress is implicated in liver damage, worsening disease outcome. Hence, stress could play a role in disrupting liver homeostasis, a concept that has not been fully explored. Here, in a murine model of TAA-induced liver fibrosis we identified nerve growth factor (NGF) to be a crucial regulator of the stress-induced fibrogenesis signaling pathway as it activates its receptor p75 neurotrophin receptor (p75NTR), increasing liver damage. Additionally, blocking the NGF decreased liver fibrosis whereas treatment with recombinant NGF accelerated the fibrotic process to a similar extent than stress challenge. We further show that the fibrogenesis induced by stress is characterized by specific changes in the hepatoglycocode (increased ß1,6GlcNAc-branched complex N-glycans and decreased core 1 O-glycans expression) which are also observed in patients with advanced fibrosis compared to patients with a low level of fibrosis. Our study facilitates an understanding of stress-induced liver injury and identify NGF signaling pathway in early stages of the disease, which contributes to the established fibrogenesis.

Exercise Training Attenuates Cirrhotic Cardiomyopathy.

Cirrhotic cardiomyopathy is a condition where liver cirrhosis is associated with cardiac dysfunction. Triggers and blockers of cirrhotic cardiomyopathy are poorly understood, which might compromise the prognosis of chronic liver disease patients. We tested whether exercise training would reduce liver damage induced by thioacetamide and prevent liver cirrhosis-associated cardiomyopathy. Wistar rats were divided into three groups: control, thioacetamide (TAA), or TAA plus exercise. Thioacetamide increased liver weight and serum alanine aminotransferase and aspartate aminotransferase levels. Also, TAA treatment was involved with hepatic nodule formation, fibrotic septa, inflammatory infiltration, and hepatocyte necrosis. The exercise group presented with a reduction in liver injury status. We found that liver injury was associated with disordered cardiac hypertrophy as well as diastolic and systolic dysfunction. Exercise training attenuated cirrhosis-associated cardiac remodeling and diastolic dysfunction and prevented systolic impairment. These results provided insights that exercise training can mitigate cirrhotic cardiomyopathy phenotype. Graphical Abstract Exercise training attenuated liver injury as well as cirrhosis-associated cardiac remodeling and diastolic dysfunction and prevented systolic impairment.

Myocardial Dysfunction in Cirrhotic Cardiomyopathy is Associated with Alterations of Phospholamban Phosphorylation and IL-6 Levels.

BACKGROUND: Decreased cardiac contractility has been observed in cirrhosis, but the mechanisms that initiate and maintain cardiac dysfunction are not entirely understood. AIM OF THE STUDY: We test the hypothesis that cirrhotic cardiomyopathy is related to deterioration of myocardial contractility due to alterations in calcium-handling proteins expression. In addition, we evaluated whether cardiac pro-inflammatory cytokine levels are associated with this process. METHODS: Cirrhosis was induced by thioacetamide (TAA, 100 mg/kg/i.p., twice weekly for eight weeks). The myocardial performance was evaluated in isolated left ventricle papillary muscles under basal conditions and after inotropic challenge. The cardiac calcium handling protein expression was detected by Western blotting. Cardiac TNF-α and IL-6 levels were measured by ELISA. RESULTS: Thioacetamide induced liver cirrhosis, which was associated with cirrhotic cardiomyopathy characterized by in vivo left ventricular diastolic and systolic dysfunction as well as cardiac hypertrophy. In vitro baseline myocardial contractility was lower in cirrhosis. Also, myocardial responsiveness to post-rest contraction stimulus was declined. Protein expression for RYR2, SERCA2, NCX, pPBL Ser16 and L-type calcium channel was quantitatively unchanged; however, pPBL Thr17 was significantly lower while IL-6 was higher. CONCLUSIONS: Our study demonstrates that cirrhotic cardiomyopathy is associated with decreased cardiac contractility with alteration of phospholamban phosphorylation in association with higher cardiac pro-inflammatory IL-6 levels. These findings provided molecular and functional insights about the effects of liver cirrhosis on cardiac function.

High sucrose diet attenuates oxidative stress, inflammation and liver injury in thioacetamide-induced liver cirrhosis.

AIMS: Liver cirrhosis is the main chronic liver disease and is considered a catabolic disease. Cirrhotic patients have a low energy intake and high energy expenditure at rest, leading to metabolic disorders. Malnutrition is associated with complications of cirrhosis and has been shown that a nutritional intervention with increase of energy intake improves the survival of cirrhotic patients. Therefore, our aim was to evaluate the effect of a high sucrose diet in the liver of animals with cirrhosis induced by thioacetamide and investigate the mechanism involved. MAIN METHODS: Male Wistar rats were divided into three groups: Control; Thioacetamide; and Thioacetamide + high sucrose diet. The thioacetamide was administrated (100 mg kg-1) intraperitoneally and the sucrose was offered in drinking water (300 g L-1). KEY FINDINGS: The administration of thioacetamide was associated with fibrosis and inflammatory infiltrate in the liver and increased levels of transaminases enzymes. The high sucrose diet promoted a reduction of theses parameters in cirrhotic rats. The malnutrition observed in cirrhotic rats was attenuated by the high sucrose diet shown by the improvements in weight loss, subcutaneous fat, and caloric intake. The high sucrose diet also attenuated the oxidative stress present in the liver of animals with thioacetamide-induced cirrhosis. SIGNIFICANCE: The high sucrose diet had anti-inflammatory and anti-oxidant effects in the liver of animals with thioacetamide-induced cirrhosis. In addition, the high sucrose diet also improved malnutrition and catabolism present in cirrhosis. Thus, a high sucrose diet may be a therapeutic option for cirrhotic patients in a catabolic state.

Effects of melatonin against thioacetamide-induced testicular toxicity in rats / Efectos de la melatonina contra la toxicidad testicular inducida por tioacetamida en ratas

SUMMARY: This study aimed to investigate the changes in testis tissue of thioacetamide-induced rats and the effect of melatonin on these changes. Thirty-five male Wistar Albino rats were divided into five groups. Group I; Control (n=7), Group II; Melatonin (Mel) (10 mg/kg) a single dose (i.p)(n=7), Group III; Thioacetamide (TAA) (300 mg/kg) (i.p) 2 times with 24 hour intervals (n=7), Group IV; TAA (300 mg/kg) was administered at 24-hour intervals, afterwards of 10 mg/kg single dose of Mel (n=7), Group V; Mel was administered 10 mg/kg a single dose 24 hours before the administration of TAA (n=7). Testis was evaluated histologically, immunohistochemically (Heat Shock Proteins (HSP) 70 and 90), blood serum testosterone, total antioxidant status(TAS) and total oxidant status(TOS) in tissue. The tissue sections of Group III decreased seminiferous tubule diameters, and germinal epithelium spills were observed. HSP70 and HSP90 expressions were increased. There wasn't a statistically significant change in testosterone levels among the groups. While TAS levels decreased in Group III compared to control, TOS levels didn't change. HSP70 and HSP90 decreased in groups with Mel-treated. Mel was found to have both protective and therapeutic effects. According to our results, the therapeutic effect of Mel in thioacetamide-induced acute testicular injury is greater than its protective effect.

RESUMEN: Este estudio tuvo como objetivo investigar los cambios en el tejido testicular de ratas inducidas por tioacetamida y el efecto de la melatonina en estos cambios. Treinta y cinco ratas macho Wistar Albino se dividieron en cinco grupos. Grupo I; Control (n = 7), Grupo II; Melatonina (Mel) (10 mg / kg) una dosis única (i.p) (n = 7), Grupo III; Tioacetamida (TAA) (300 mg / kg) (i.p) 2 veces con intervalos de 24 horas (n = 7), Grupo IV; TAA (300 mg / kg) se administró a intervalos de 24 horas, luego de una dosis única de 10 mg / kg de Mel (n = 7), Grupo V; Mel recibió 10 mg / kg de una dosis única 24 horas antes de la administración de TAA (n = 7). Los testículos se evaluaron histológicamente, inmunohistoquímicamente (proteínas de choque térmico (PCT) 70 y 90), testosterona en suero sanguíneo, estado antioxidante total (EAT) y estado oxidante total (EOT) en el tejido. En secciones de tejido del Grupo III se observó disminución de los diámetros de los túbulos seminíferos y derrames en el epitelio germinal. Se aumentaron las expresiones HSP70 y HSP90. No hubo un cambio estadísticamente significativo en los niveles de testosterona entre los grupos. Mientras que los niveles de EAT disminuyeron en el Grupo III en comparación con el control, los niveles de EOT no cambiaron. HSP70 y HSP90 disminuyeron en los grupos tratados con Mel. Se descubrió que Mel tenía efectos protectores y terapéuticos. Según nuestros resultados, el efecto terapéutico de Mel en la lesión testicular aguda inducida por tioacetamida es mayor que su efecto protector.

Suppression of thioacetamide-induced hepatic injury in rats treatment with resveratrol: role of mammalian target of rapamycin (mTOR) cell signaling / Supresión de la lesión hepática inducida por tioacetamida en ratas tratadas con resveratrol: rol de la vía de señalización mTOR (mammalian target of rapamycin)

Chronic hepatotoxicity is a debilitating and frequently life-threatening disease resulting in progressive liver failure. The toxic chemical, thioacetamide (TAA) is used to evaluate hepatoprotective agents, and the polyphenolic compound, resveratrol was proposed as a novel treatment for diseases with hyperactivation of the mammalian target of rapamycin (mTOR) cell signaling pathway. This analysis sought to investigate the potential protective effect of resveratrol against liver injury induced by TAA via the inhibition of hepatic mTOR. Model group rats received several injections of TAA (200 mg/kg; twice a week for 8 weeks) before being sacrificed at week 10 and the protective group was pretreated with resveratrol (20 mg/kg) daily for two weeks prior to TAA injections and continued receiving both agents until the end of the experiment. Harvested liver tissues were examined using light microscopy and liver homogenates were assayed for biomarkers of inflammation and assessed the levels of mTOR protein in all animal groups. In addition, blood samples were assayed for biomarkers of liver injury enzyme. TAA substantially damaged the hepatic tissue of the model group such as infiltration of inflammatory cells, vacuolated cytoplasm, dark pyknotic nuclei, and dilated congested blood vessel that were effectively protected by resveratrol. Resveratrol also significantly (p<0.05) inhibited TAA-induced mTOR, high sensitivity c-reactive protein (hs-CRP), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in harvested liver homogenates and blood samples. Thus, we conclude that resveratrol effectively protects against TAA-induced hepatotoxicity in rats, possibly due to the inhibition of mTOR and inflammation.

La hepatotoxicidad crónica es una enfermedad debilitante y potencialmente mortal que produce insuficiencia hepática progresiva. La toxicidad del químico de la tioacetamida (TAA) se utiliza para evaluar los agentes hepatoprotectores y el compuesto polifenólico, resveratrol, se propuso como un nuevo tratamiento para enfermedades con hiperactivación de la vía de señalización celular mTOR (mammalian Target of Rapamycin). Aquí buscamos investigar el posible efecto protector del resveratrol contra la lesión hepática inducida por TAA a través de la inhibición de la vía de señalización mTOR en hepatocitos. Las ratas del grupo modelo recibieron varias inyecciones de TAA (200 mg / kg; dos veces por semana durante 8 semanas) antes de ser sacrificadas en la semana 10 y el grupo protector se trató previamente con resveratrol (20 mg / kg) diariamente durante dos semanas antes de las inyecciones de TAA y continuó recibiendo ambos agentes hasta el final del experimento. Se examinaron los tejidos hepáticos recolectados usando microscopía óptica y se analizaron los homogeneizados hepáticos para detectar biomarcadores de inflamación y se evaluaron los niveles de proteína mTOR en todos los grupos de animales. Además, se analizaron muestras de sangre para detectar biomarcadores de la enzima de lesión hepática. TAA dañó sustancialmente el tejido hepático del grupo modelo, con infiltración de células inflamatorias, citoplasma vacuolado, núcleos picnóticos oscuros y vasos sanguíneos congestionados dilatados que estaban efectivamente protegidos por el resveratrol. El resveratrol también inhibió significativamente (p <0.05) mTOR, proteína C-reactiva (hs-CRP), factor de necrosis tumoral alfa (TNF-α), interleucina-6 (IL-6), alanina aminotransferasa (ALT ) y aspartato aminotransferasa (AST) en las muestras de sangre y de hígados recolectados. En conclusión, el resveratrol protege eficazmente contra la hepatotoxicidad inducida por TAA en ratas, posiblemente debido a la inhibición de mTOR y de la inflamación.

Burdock (Arctium lappa L.) root attenuates preneoplastic lesion development in a diet and thioacetamide-induced model of steatohepatitis-associated hepatocarcinogenesis.

Nonalcoholic steatohepatitis (NASH) is considered growing risk factor for hepatocellular carcinoma development in high-income countries. Diet- and chemically induced rodent models have been applied for the translational study of NASH-associated hepatocarcinogenesis due to their morphological and molecular similarities to the corresponding human disease. Arctium lappa L. (burdock) root tea has been extensively consumed in Traditional Chinese Medicine due to its potential therapeutic properties. Indeed, the bioactive compounds of A. lappa root, as the polyphenols, have already showed antioxidant and anti-inflammatory properties in different in vivo and in vitro bioassays. In this study, we investigated whether burdock root ethanolic extract (BRE) administration attenuates NASH-associated hepatocarcinogenesis. Eight-week-old male Wistar rats received choline-deficient high-fat diet for 8 weeks and multiple thioacetamide doses for 4 weeks in order to induce NASH and preneoplastic glutathione-S-transferase pi (GST-P)+ preneoplastic foci. Subsequently, rats were treated with BRE (100 or 200 mg/kg body weight) or vehicle by oral gavage for 2 weeks. BRE displayed high levels of chlorogenic and caffeic acids and BRE administration reduced total fatty acid and lipid hydroperoxide levels, while increasing the activities of antioxidant superoxide dismutase and catalase enzymes in the liver. Furthermore, burdock intervention diminished the size of GST-P+ remodeling preneoplastic lesions (PNLs) and displayed a trend on reducing hepatocyte proliferation (Ki-67) inside them. These findings suggest that short-term exposure to BRE alleviated remodeling PNL development in NASH-associated hepatocarcinogenesis.

Antioxidant and Hepatoprotective Effects of Croton hypoleucus Extract in an Induced-Necrosis Model in Rats.

The aim of this study was to evaluate the antioxidant and hepatoprotective activity of Croton hypoleucus (EC). The present work reports the first pharmacological, toxicological, and antioxidant studies of EC extract on liver injury. Liver necrosis was induced by thioacetamide (TAA). Five groups were established: Croton Extract (EC), thioacetamide (TAA), Croton extract with thioacetamide (EC + TAA), vitamin E with thioacetamide (VE + TAA) and the positive control and vehicle (CT). For EC and EC + TAA, Wistar rats (n = 8) were intragastrically pre-administered for 4 days with EC (300 mg/kg.day) and on the last day, EC + TAA received a single dose of TAA (400 mg/kg). At 24 h after damage induction, animals were sacrificed. In vitro activity and gene expression of superoxide dismutase (SOD), catalase (Cat), and Nrf2 nuclear factor were measured. The results show that EC has medium antioxidant properties, with an IC50 of 0.63 mg/mL and a ferric-reducing power of 279.8 µM/mg. Additionally, EC reduced hepatic damage markers at 24 h after TAA intoxication; also, it increased SOD and Cat gene expression against TAA by controlling antioxidant defense levels. Our findings demonstrated the hepatoprotective effect of EC by reducing hepatic damage markers and controlling antioxidant defense levels. Further studies are necessary to identify the mechanism of this protection.

Improved histoarchitectural changes with angiotensin receptor blockers in early testicular and cauda toxicity in rats / Mejora de los cambios en la histoarquitectura con bloqueadores de receptores de angiotensina en la toxicidad precoz testicular y de cauda en ratas

SUMMARY: Reproductive dysfunction is a complication for many diseases and toxins. Its early diagnosis and treatment are immensely important. Here the morphological histoarchitecture changes in early testicular and cauda toxicity before and after treatment with angiotensin receptor blockers were evaluated. Low-grade testicular damage was induced using thioacetamide (TAA, 50 mg/kg/day) intraperitoneally for two weeks in rats. The rats were randomly divided into four groups (n = 8) treated daily orally for three weeks as follows: Normal control (distilled water), TAA (positive control), TAA+candesartan (0.2 mg/kg) and TAA+losartan (7.5 mg/kg). Serum testosterone and testicular malondialdehyde and glutathione were measured. The changes in histoarchitecture of testis and cauda epididymis were evaluated by hematoxylin and eosin for general structure, Masson's trichrome for collagen, periodic acid Schiff for basement membrane, and caspase-3 and proliferating cell nuclear antigen (PCNA) for immunohistochemical analysis. The TAA-rats showed decreases of serum testosterone and testicular glutathione, increases in testicular malondialdehyde, degenerative changes and apoptosis in germ cells, thickening of tubular basal lamina and increases in expression of caspase 3, and decreases in expression of PCNA. The ARBs (candesartan and losartan) significantly reversed these changes with non-significant differences in-between. Treatment with ARBs (candesartan and losartan) significantly reversed TAA-induced low-grade testicular and cauda toxicity in rats. This could be potentially useful for early treatment of male patients with occupational toxicant-induced reproductive dysfunction especially if they are using ARBs for other comorbidities.

RESUMEN: La disfunción reproductiva es una complicación por muchas enfermedades y toxinas. Su diagnóstico y tratamiento tempranos son inmensamente importantes. Aquí se evaluaron los cambios morfológicos en la histoarquitectura en la toxicidad precoz testicular y cauda antes y después del tratamiento con bloqueadores de receptores de angiotensina. Se indujo daño testicular de bajo grado usando tioacetamida (TAA, 50 mg / kg / día) por vía intraperitoneal durante dos semanas en ratas. Las ratas se dividieron aleatoriamente en cuatro grupos (n = 8) tratados diariamente por vía oral durante tres semanas de la siguiente manera: control normal (agua destilada), TAA (control positivo), TAA + candesartan (0,2 mg / kg) y TAA + losartán (7,5 mg / kg). Se midieron la testosterona sérica, el malondialdehído testicular y el glutatión. Los cambios en la histoarquitectura de los testículos y la epidermis de la cauda se evaluaron mediante Hematoxilina y Eosina para determinar la estructura general, con tricrómicro de Masson para el colágeno, ácido periódico de Schiff para la membrana basal y la caspasa-3 y el antígeno nuclear de células proliferantes (PCNA) para análisis inmunohistoquímico. Las ratas TAA mostraron disminución de la testosterona sérica y glutatión testicular, aumentos en el malondialdehído testicular, cambios degenerativos y apoptosis en células germinales, engrosamiento de la lámina basal tubular y aumentos en la expresión de la caspasa 3, y disminución en la expresión de PCNA. Los ARB (candesartán y losartán) revirtieron significativamente estos cambios con diferencias no significativas en el medio. El tratamiento con BRA (candesartán y losartán) revirtió significativamente la toxicidad testicular y cauda inducida por TAA en ratas. Esto podría ser potencialmente útil para el tratamiento temprano de pacientes con disfunción reproductiva inducida por tóxicos ocupacionales, especialmente si están usando BRA para otras comorbilidades.

Rebaudioside A administration prevents experimental liver fibrosis: an in vivo and in vitro study of the mechanisms of action involved.

Rebaudioside A (Reb A) is a diterpenoid isolated from the leaves of Stevia rebaudiana (Bertoni) that has been shown to possess pharmacological activity, including anti-inflammatory and antioxidant properties. However, the ability of Reb A to prevent liver injury has not been evaluated. Therefore, we aimed to study the potential of Reb A (20 mg/kg; two times daily intraperitoneally) to prevent liver injury induced by thioacetamide (TAA) administration (200 mg/kg; three times per week intraperitoneally). In addition, cocultures were incubated with either lipopolysaccharide or ethanol. Antifibrotic, antioxidant and immunological responses were evaluated. Chronic TAA administration produced considerable liver damage and distorted the liver parenchyma with the presence of prominent thick bands of collagen. In addition, TAA upregulated the expression of α-smooth muscle actin, transforming growth factor-ß1, metalloproteinases 9, 2 and 13, and nuclear factor kappaB and downregulated nuclear erythroid factor 2. Reb A administration prevented all of these changes. In cocultured cells, Reb A prevented the upregulation of genes implicated in fibrotic and inflammatory processes when cells were exposed to ethanol and lipopolysaccharide. Altogether, our results suggest that Reb A prevents liver damage by blocking oxidative processes via upregulation of nuclear erythroid factor 2, exerts immunomodulatory effects by downregulating the nuclear factor-κB system and acts as an antifibrotic agent by maintaining collagen content.

Antioxidant and immunomodulatory activity induced by stevioside in liver damage: In vivo, in vitro and in silico assays.

AIMS: Stevioside is a diterpenoid obtained from the leaves of Stevia rebaudiana (Bertoni) that exhibits antioxidant, antifibrotic, antiglycemic and anticancer properties. Therefore, we aimed to study whether stevioside has beneficial effects in liver injury induced by long-term thioacetamide (TAA) administration and investigated the possible underlying molecular mechanism using in vivo, in vitro and in silico approaches. MAIN METHODS: Liver injury was induced in male Wistar rats by TAA administration (200 mg/kg), intraperitoneally, three times per week. Rats received saline or stevioside (20 mg/kg) twice daily intraperitoneally. In addition, cocultures were incubated with either lipopolysaccharide or ethanol. Liver injury, antioxidant and immunological responses were evaluated. KEY FINDINGS: Chronic TAA administration induced significant liver damage. In addition, TAA upregulated the protein expression of nuclear factor (NF)-κB, thus increasing the expression of proinflammatory cytokines and decreasing the antioxidant capacity of the liver through downregulation of nuclear erythroid factor 2 (Nrf2). Notably, stevioside administration prevented all of these changes. In vitro, stevioside prevented the upregulation of several genes implicated in liver inflammation when cocultured cells were incubated with lipopolysaccharide or ethanol. In silico assays using tumor necrosis factor receptor (TNFR)-1 and Toll-like receptor (TLR)-4-MD2 demonstrated that stevioside docks with TNFR1 and TLR4-MD2, thus promoting an antagonistic action against this proinflammatory mediator. SIGNIFICANCE: Collectively, these data suggest that stevioside prevented liver damage through antioxidant activity by upregulating Nrf2 and immunomodulatory activity by blocking NF-κB signaling.