Therapeutic Effect of Melatonin on CCl4-Induced Fibrotic Liver Model by Modulating Oxidative Stress, Inflammation, and TGF-ß1 Signaling Pathway in Pinealectomized Rats.

The study aimed to determine the CCl4-induced liver fibrosis model in pinealectomized rats and biochemically, immunohistochemically, and histopathologically investigate the therapeutic effect of melatonin on liver fibrosis. The surgical procedure for pinealectomy was performed at the beginning of the study, and the sham and pinealectomized rats were administered CCl4 dissolved in corn oil (1:1) alone every other day to induce liver fibrosis or together with melatonin (10 mg/kg) therapy for 15 days. Melatonin is an essential therapeutic agent and offers an alternative therapeutic strategy in CCl4-induced liver fibrosis by suppressing inflammation, oxidative stress, and the TGF-ß1 signaling pathway. Treatment with melatonin ameliorated CCl4-induced liver fibrosis by restoring hepatocellular damage and reducing plasma AST, ALT, and ALP values. Melatonin increases the activity of SOD and CAT, which are important enzymes for antioxidant defence, and raises GSH levels, which further enhances antioxidant function. Also, melatonin reduced hepatic inflammation (IL-6 and IL-1ß) and oxidative stress indices. Moreover, histopathological changes and immunohistochemical expression of TGF-ß1 were restored following melatonin supplementation in the CCl4-induced liver fibrosis model in pinealectomized rats. Our study shows that melatonin supplementation has a beneficial effect in protecting the liver fibrosis induced by CCl4 in pinealectomized rats.

Therapeutic role of melatonin on acrylamide-induced hepatotoxicity in pinealectomized rats: Effects on oxidative stress, NF-κB signaling pathway, and hepatocellular proliferation.

Acrylamide (AA) is formed in some foods by the cooking process at high temperatures, and it could be a carcinogen in humans and rodents. The purpose of the current study was to reveal the possible protective effects of melatonin against AA-induced hepatic oxidative stress, hepatic inflammation, and hepatocellular proliferation in pinealectomized rats. Hence, the sham and pinealectomized rats were consecutively given AA alone (25 mg/kg) or with melatonin (10 mg/kg) for 21 days. Melatonin acts as an antioxidant, anti-inflammatory, and antiapoptotic agent and introduces as a therapeutic strategy for AA-induced hepatotoxicity. Melatonin supplementation reduced AA-caused liver damage by decreasing the serum AST, ALT, and ALP levels. Melatonin raised the activities of SOD and CAT and levels of GSH and suppressed hepatic inflammation (TNF-α) and hepatic oxidative stress in liver tissues. Moreover, histopathological alterations and the disturbances in immunohistochemical expression of NF-κB and Ki67 were improved after melatonin treatment in AA-induced hepatotoxicity. Overall, our results demonstrate that melatonin supplementation exhibits adequate hepatoprotective effects against hepatotoxicity of AA on pinealectomized rat liver architecture and the tissue function through the equilibration of oxidant/antioxidant status, the regulation of cell proliferation and the suppression of the release of proinflammatory cytokines.

The relation between staging fluorine-18 fluorodeoxyglucose positron emission tomog- raphy/computed tomography metabolic parameters and tumor necrosis rate in pediatric osteosarcoma patients

Background/aim: The aim of this study was to investigate the contribution of fluorine-18 (F-18) fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging in staging of pediatric osteosarcoma patients and also to evaluate the ability of metabolic parameters from the primary tumor to predict tumor necrosis rate (TNR). Material and methods: F-18 FDG-PET/CT imaging was performed in staging 37 pediatric osteosarcoma patients. The metabolic pa- rameters SUVmax (maximum standardised uptake value), MTV (metabolic tumour volume), and TLG (total lesion glycolysis) were measured from the primary tumor. TNR level of the primary tumor was histopathologically measured after standard neoadjuvant chemotherapy treatment. The contribution of F-18 FDG-PET/CT to staging of pediatric osteosarcoma patients and the accuracy of metabolic parameters of the primary tumor to predict TNR were analized by regression analysis. Results: MTV and TLG of the primary tumor were found to efficiently predict histopathologic TNR, whereas SUVmax was not (P = 0.012, P = 0.027, P = 0.25, respectively). Also 5 of 12 patients (41.6%) who were initially defined as localised osteosarcoma were upstaged in consequence of staging F-18 FDG-PET/CT findings. Conclusion: F-18 FDG-PET/CT staging in pediatric osteosarcoma patients can effectively distinguish metastatic-localised disease. MTV and TLG values are important parameters, which can efficiently be used to predict TNR.