Drug-Induced Liver Injury—Perspectives from Pathology

Curcumin Ameliorates Doxorubicin-Induced Cardiotoxicity and Hepatotoxicity Via Suppressing Oxidative Stress and Modulating iNOS, NF-κB, and TNF-α in Rats

Doxorubicin (DOX) is one of the widely used anti-tumor drugs. However, DOX-induced cardiotoxicity (DIC) and hepatotoxicity (DIH) are among the side effects that limited its therapeutic efficiency and clinical applicability. This study aimed to investigate the cardioprotective and hepatoprotective potentials of curcumin (CMN)-a bioactive polyphenolic compound-in alleviating DOX-induced cardiotoxicity (DIC) and hepatotoxicity (DIH) in male rats. A single intraperitoneal (i.p.) dose of DOX (20 mg/kg) was used to induce DIC and DIH. DOX-intoxicated rats were co-treated with CMN (100 mg/kg, oral) for 10 days before and 5 days after a single dose of DOX. We studied the anti-inflammatory and anti-oxidative activities of CMN on biochemical and immunohistochemical aspects. DOX disrupted cardiac and hepatic functions and stimulated oxidative stress and inflammation in both tissues that was confirmed biochemically and immunohistochemically. DOX enhanced inflammatory interferon-gamma (IFN-γ) and upregulated immunoexpression of nuclear factor-κB (NF-κB), inducible nitric oxide synthase (iNOS), and tumor necrosis factor-alpha (TNF-α). DOX induced structural alterations in both cardiac and hepatic tissues. CMN demonstrated cardioprotective potential through reducing cardiac troponin I (cTn1) and aspartate amino transaminase (AST). In addition, CMN significantly ameliorated liver function through decreasing alanine amino transaminase (ALT) and, gamma-glutamyl transferase (GGT), total cholesterol (TC), and triglycerides (TG). CMN demonstrated anti-inflammatory potential through decreasing IFN-γ levels and immunoexpression of iNOS, NF-κB, and TNF-α. Histopathologically, CMN restored DOX-associated cardiac and liver structural alterations. CMN showed anti-oxidative and anti-inflammatory potentials in both the cardiac and hepatic tissues. In addition, cTn1, IFN-γ, and AST could be used as blood-based biomarkers.

Toxicity of carbon tetrachloride, free radicals and role of antioxidants

Several chemicals, including environmental toxicants and clinically useful drugs, cause severe cellular damage to different organs of our body through metabolic activation to highly reactive substances such as free radicals. Carbon tetrachloride is an organic compound of which chemical formula is CCl₄. CCl₄ is strong toxic in the kidney, testicle, brain, heart, lung, other tissues, and particularly in the liver. CCl₄ is a powerful hepatoxic, nephrotoxic and prooxidant agent which is widely used to induce hepatotoxicity in experimental animals and to create hepatocellular carcinoma, hepatic fibrosis/cirrhosis and liver injury, chemical hepatitis model, renal failure model, and nephrotoxicity model in recent years. The damage-causing mechanism of CCl₄ in tissues can be explained as oxidative damage caused by lipid peroxidation which starts after the conversion of CCl₄ to free radicals of highly toxic trichloromethyl radicals (•CCl₃) and trichloromethyl peroxyl radical (•CCl₃O₂) via cytochrome P450 enzyme. Complete disruption of lipids (i.e., peroxidation) is the hallmark of oxidative damage. Free radicals are structures that contain one or more unpaired electrons in atomic or molecular orbitals. These toxic free radicals induce a chain reaction and lipid peroxidation in membrane-like structures rich in phospholipids, such as mitochondria and endoplasmic reticulum. CCl₄-induced lipid peroxidation is the cause of oxidative stress, mitochondrial stress, endoplasmic reticulum stress. Free radicals trigger many biological processes, such as apoptosis, necrosis, ferroptosis and autophagy. Recent researches state that the way to reduce or eliminate these CCl₄-induced negative effects is the antioxidants originated from natural sources. For normal physiological function, there must be a balance between free radicals and antioxidants. If this balance is in favor of free radicals, various pathological conditions occur. Free radicals play a role in various pathological conditions including Pulmonary disease, ischemia / reperfusion rheumatological diseases, autoimmune disorders, cardiovascular diseases, cancer, kidney diseases, hypertension, eye diseases, neurological disorders, diabetes and aging. Free radicals are antagonized by antioxidants and quenched. Antioxidants do not only remove free radicals, but they also have anti-inflammatory, anti-allergic, antithrombotic, antiviral, and anti-carcinogenic activities. Antioxidants contain high phenol compounds and antioxidants have relatively low side effects compared to synthetic drugs. The antioxidants investigated in CCI₄ toxicity are usually antioxidants from plants and are promising because of their rich resources and low side effects. Data were investigated using PubMed, EBSCO, Embase, Web of Science, DOAJ, Scopus and Google Scholar, Carbon tetrachloride, carbon tetrachloride-induced toxicity, oxidative stress, and free radical keywords. This study aims to enlighten the damage-causing mechanism created by free radicals which are produced by CCl₄ on tissues/cells and to discuss the role of antioxidants in the prevention of tissue/cell damage. In the future, Antioxidants can be used as a therapeutic strategy to strengthen effective treatment against substances with high toxicity such as CCl₄ and increase the antioxidant capacity of cells.

The protective potential of alpha lipoic acid on amiodarone-induced pulmonary fibrosis and hepatic injury in rats

Amiodarone (AMD) is a widely used antiarrhythmic drug prescribed to treat cardiac tachyarrhythmias; however, AMD has been reported to provoke pulmonary fibrosis (PF) and hepatotoxicity. This study aimed to investigate the influence of alpha lipoic acid (ALA) on AMD-induced PF and hepatotoxicity in male Wistar rats. AMD administration resulted in elevated lung contents of hydroxyproline (Hyp), malondialdehyde (MDA), and increased serum levels of transforming growth factor beta-1 (TGF-β1), interferon-γ (IFN-γ), alanine amino transaminase (ALT), aspartate amino transaminase (AST), total cholesterol (TC), and glucose. On the other side, lung content of glutathione reduced (GSH) and serum levels of total anti-oxidant capacity (TAC) were significantly decreased. Histopathologically, AMD caused PF, produced a mild hepatic injury, and increased expression of alpha smooth muscle actin (α-SMA). Treatment with ALA produced a significant reversal of the oxidative stress, fibrosis, and inflammation parameters with reductions in α-SMA expressions, leading to amelioration of histopathological lesions. ALA might provide supportive therapy in AMD-receiving cardiovascular patients.