Protective effects of paclitaxel on thioacetamide-induced liver fibrosis in a rat model

Apocynin alleviates thioacetamide-induced acute liver injury: Role of NOX1/NOX4/NF-κB/NLRP3 pathways

The liver has a distinctive capacity to regenerate, yet severe acute injury can be life-threatening if not treated appropriately. Inflammation and oxidative stress are central processes implicated in the pathophysiology of acute livery injury. NOX isoforms are important enzymes for ROS generation, NF-κB and NLRP3 activation, its inhibition could be vital in alleviating acute liver injury (ALI). Here in our study, we used apocynin, a natural occurring potent NOX inhibitor, to exploreits potential protective effect against thioacetamide (TAA)-induced ALI through modulating crucial oxidative and inflammatory pathways. Rats were injected once with TAA (500 mg/kg/i.p) and treated with apocynin (10 mg/kg/i.p) twice before TAA challenge. Sera and hepatic tissues were collected for biochemical, mRNA expression, western blot analysis and histopathological assessments. Pretreatment with apocynin improved liver dysfunction evidenced by decreased levels of aminotransferases, ALP, GGT and bilirubin. Apocynin reduced mRNA expression of NOX1 and NOX4 which in turn alleviated oxidative stress, as shown by reduction in MDA and NOx levels, and elevation in GSH levels andcatalase and SOD activities. Moreover, apocynin significantly reduced MPO gene expression. We also demonstrate that apocynin ameliorated inflammation through activating IκBα and suppressing IKKα, IKKβ, NF-κBp65 and p-NF-κBp65, IL-6 andTNF-α. Additionally, apocynin potentiated the gene expression of anti-inflammatory IL-10 and reduced levels of hepatic NLRP3, Caspase-1 and IL-1β. These results suggest that apocynin protects against ALI in association with the inhibition of NOX1 and NOX4 and regulating oxidative and inflammatory pathways.

Re-positioning of low dose paclitaxel against depressive-like behavior and neuroinflammation induced by lipopolysaccharide in rats: Crosstalk between NLRP3/caspase-1/IL-1β and Sphk1/S1P/ NF-κB signaling pathways

AIMS

Depression is a potentially fatal illness affecting millions of individuals worldwide, across all age groups. Neuroinflammation is a key factor in depression development. Paclitaxel (PXL), a well-known chemotherapeutic agent has been used as therapy for several types of cancer. This study aims to evaluate the ameliorative effect of low-dose PXL against lipopolysaccharide (LPS)-induced depression in rats.

MATERIALS AND METHODS

Adult male Sprague-Dawley rats were administrated a single dose of LPS (5 mg/kg, i.p.); 2 h later, rats received PXL (0.3 mg/kg, i.p. three times/week) for one week.

KEY FINDINGS

Low-dose PXL alleviated LPS-induced depressive-like behavior in rats as evidenced by significantly improving behavioral changes in both forced swim test (FST) and open field test (OFT), successfully mitigated depletion of monoamines (serotonin, norepinephrine, and dopamine), in addition to markedly decreasing lipid peroxidation with antioxidant levels elevation in brain tissues. Low-dose PXL substantially decreased inflammation triggered by LPS in brain tissue via repressing the expression of NLRP3 and its downstream markers level, caspase-1 and IL-1β jointly with a corresponding decrease in proinflammatory cytokine levels (TNF-α). Furthermore, low-dose PXL remarkably down-regulated Sphk1/S1P signaling pathway. Concurrent with these biochemical findings, there was a noticeable improvement in the brain tissue's histological changes.

SIGNIFICANCE

These findings prove the role of low-dose PXL in treatment of LPS-induced neuroinflammation and depressive-like behavior through their anti-depressant, antioxidant and anti-inflammatory actions. The suggested molecular mechanism may entail focusing the interconnection among Sphk1/S1P, and NLRP3/caspase-1/IL-1β signaling pathways. Hence PXL could be used as a novel treatment against LPS-induced depression.

Recent Advances in Research on Active Compounds Against Hepatic Fibrosis

BACKGROUND

Almost all chronic liver diseases cause fibrosis, which can lead to cirrhosis and eventually liver cancer. Liver fibrosis is now considered to be a reversible pathophysiological process and suppression of fibrosis is necessary to prevent liver cancer. At present, no specific drugs have been found that have hepatic anti-fibrotic activity.

OBJECTIVE

The research progress of anti-hepatic fibrosis compounds in recent ten years was reviewed to provide a reference for the design and development of anti-hepatic fibrosis drugs.

METHODS

According to the structure of the compounds, they are divided into monocyclic compounds, fused-heterocyclic compounds, and acyclic compounds.

RESULTS

In this article, the natural products and synthetic compounds with anti-fibrotic activity in recent ten years were reviewed, with emphasis on their pharmacological activity and structure-activity relationship (SAR).

CONCLUSION

Most of these compounds are natural active products and their derivatives, and there are few researches on synthetic compounds and SAR studies on natural product.

Unveiling thioacetamide-induced toxicity: Multi-organ damage and omitted bone toxicity

Thioacetamide (TAA), a widely employed hepatotoxic substance, has gained significant traction in the induction of liver failure disease models. Upon administration of TAA to experimental animals, the production of potent oxidative derivatives ensues, culminating in the activation of oxidative stress and subsequent infliction of severe damage upon multiple organs via dissemination through the bloodstream. This review summarized the various organ damages and corresponding mechanistic explanations observed in previous studies using TAA in toxicological animal experiments. The principal pathological consequences arising from TAA exposure encompass oxidative stress, inflammation, lipid peroxidation, fibrosis, apoptosis induction, DNA damage, and osteoclast formation. Recent in vivo and in vitro studies on TAA bone toxicity have confirmed that long-term high-dose use of TAA not only induces liver damage in experimental animals but also accompanies bone damage, which was neglected for a long time. By using TAA to model diseases in experimental animals and controlling TAA dosage, duration of use, and animal exposure environment, we can induce various organ injury models. It should be noted that TAA-induced injuries have a time-dependent effect. Finally, in our daily lives, especially for researchers, we should take precautions to minimize TAA exposure and reduce the probability of related organ injuries.

Molecular mechanisms in thioacetamide-induced acute and chronic liver injury models

Thioacetamide (TAA) undergoes bioactivation in the liver by the CYP450 2E1 enzyme, resulting in the formation of TAA-S-oxide and TAA-S-dioxide. TAA-S-dioxide induces oxidative stress via lipid peroxidation of the hepatocellular membrane. A single TAA dose (50-300 mg/kg) administration initiates hepatocellular necrosis around the pericentral region after its covalent binding to macromolecules in the liver. Intermittent TAA administration (150-300 mg/kg, weekly thrice, for 11-16 weeks) activates transforming growth factor (TGF)-β/smad3 downstream signaling in injured hepatocytes, causing hepatic stellate cells (HSCs) to acquire myofibroblast like phenotype. The activated HSCs synthesize a variety of extracellular matrix, leading to liver fibrosis, cirrhosis, and portal hypertension. The TAA induced liver injury varies depending on the animal model, dosage, frequency, and routes of administration. However, TAA induces hepatotoxicity in a reproducible manner, and it is an ideal model to evaluate the antioxidant, cytoprotective, and antifibrotic compounds in experimental animals.

Low dose Taxol ameliorated renal fibrosis in mice with diabetic kidney disease by downregulation of HIPK2

Our previous studies reported that low-dose paclitaxel (Taxol) ameliorated renal fibrosis in the unilateral ureteral obstruction and remnant kidney models. However, the regulatory role of Taxol in diabetic kidney disease (DKD) is still unclear. Herein, we observed that low-dose Taxol attenuated high glucose-increased expression of fibronectin, collagen I and collagen IV in Boston University mouse proximal tubule cells. Mechanistically, Taxol suppressed the expression of homeodomain-interacting protein kinase 2 (HIPK2) via disrupting the binding of Smad3 to HIPK2 promoter region, and consequently inhibited the activation of p53. Besides, Taxol ameliorated RF in Streptozotocin mice and db/db-induced DKD via suppression of Smad3/HIPK2 axis as well as inactivation of p53. Altogether, these results suggest that Taxol can block Smad3-HIPK2/p53 axis, thereby attenuating the progression of DKD. Hence, Taxol is a promising therapeutic drug for DKD.

Low-dose paclitaxel modulates the cross talk between the JNK and Smad signaling in primary biliary fibroblasts

OBJECTIVE

The objective of this study was to explore the molecular mechanism underlying the occurrence of benign bile duct stricture and the target of low-dose paclitaxel in the prevention of benign bile duct stricture.

METHODS

Under the stimulation of transforming growth factor beta 1, the expression of collagen type I and connective tissue growth factor were detected on isolated primary fibroblasts. The phosphorylation levels of JNK and Smad2L were detected using Western blot. The effect of low-dose paclitaxel on the transforming growth factor beta 1-induced inhibition of type I collagen and connective tissue growth factor expression and JNK and Smad2L phosphorylation was also observed.

RESULTS

Transforming growth factor beta 1 induced the secretion of type I collagen and connective tissue growth factor as well as JNK phosphorylation in biliary fibroblasts. The JNK inhibitor or siRNA-Smad2 inhibited the transforming growth factor beta 1-induced secretion of type I collagen and connective tissue growth factor. Low-dose paclitaxel inhibited the expression of type I collagen induced by transforming growth factor beta 1 and may inhibit the secretion of collagen in biliary fibroblasts.

CONCLUSION

The activation of JNK/Smad2L induced by transforming growth factor beta 1 is involved in the occurrence of benign bile duct stricture that is mediated by the overexpression of type I collagen and connective tissue growth factor, and low-dose paclitaxel may inhibit the phosphorylation of JNK/Smad2L.

Tyrosol retards induction of fibrosis in rats

Liver fibrosis, which still does not have a standard treatment due to its complex pathogenesis, is an important cause of mortality and morbidity. In this study, it was aimed to examine the possible protective and antifibrotic effects of tyrosol on the liver through histopathologic, immunohistochemical, biochemical, and molecular methods in rats with chronic liver damage induced by thioacetamide (TAA). The study was carried out in four groups with eight rats in each group. Created groups are, respectively, control, TAA, tyrosol and TAA +tyrosol. Chronic liver damage was induced in the TAA and TAA +tyrosol groups by the addition of TAA (200 mg/L) to drinking water. Tyrosol (20 mg/kg/b.w./daily) was administered by oral gavage to tyrosol and TAA +tyrosol groups for 10 weeks. The results of this study demonstrate that the consumption of tyrosol alleviated the histopathologic changes such as inflammation, degeneration, and especially fibrosis induced by TAA in the liver. In addition, administration of tyrosol significantly attenuated alpha-smooth muscle actin (α-SMA) expression and apoptosis expression. Biochemically, it was determined that tyrosol increased glutathione (GSH) level, glutathione peroxidase (GSH.Px), and catalase (CAT) activities and showed antioxidant efficacy by reducing malondialdehyde (MDA) level. Moreover, it reduced inflammation and fibrosis by decreasing gene expression levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and transforming growth factor-beta (TGF-β1). Western blot analysis also revealed similar results in TGF-β1 expression. As a result, tyrosol suppressed fibrogenesis thanks to its antioxidant, anti-inflammatory, and anti-apoptotic effects and showed an antifibrotic effect in the liver. PRACTICAL APPLICATIONS: It is stated that tyrosol, a natural phenolic antioxidant found in olive oil, has neuroprotective, cardioprotective, anti-inflammatory, and anticancer properties. In this study, tyrosol suppressed fibrogenesis thanks to its antioxidant, anti-inflammatory, and anti-apoptotic effects and showed an antifibrotic effect in the liver. Olive oil has an important place in the Mediterranean diet, which reduces the incidence of chronic diseases. It is thought that the anti-fibrotic effect of tyrosol plays a role in this feature. As a result, it is thought that tyrosol can be used to prevent or slow down chronic liver diseases.