BackgroundHeme oxygenase-1 (HO-1), an antioxidant defense enzyme, has been shown to protect against oxidant-induced liver injury. However, its role on liver fibrosis remains unclear. This study aims to elucidate the effect and the mechanism of HO-1 in nutritional fibrosing steatohepatitis in mice.MethodsMale C57BL/6J mice were fed with a methionine-choline deficient (MCD) diet for eight weeks to induce hepatic fibrosis. HO-1 chemical inducer (hemin), HO-1 chemical inhibitor zinc protoporphyrin IX (ZnPP-IX) and/or adenovirus carrying HO-1 gene (Ad-HO-1) were administered to mice, respectively. Liver injury was assessed by serum ALT, AST levels and histological examination; hepatic lipid peroxides levels were determined; the expression levels of several fibrogenic related genes were assayed by real-time quantitative PCR and Western blot.ResultsMCD feeding mice showed progressive hepatic injury including hepatic steatosis, inflammatory infiltration and fibrosis. Induction of HO-1 by hemin or Ad-HO-1 significantly attenuated the severity of liver injury. This effect was associated with the up-regulation of HO-1, reduction of hepatic lipid peroxides levels, down-regulation of inflammatory factors tumor necrosis factor-alpha, interleukin-6 and suppressor of cytokine signaling-1 as well as the pro-fibrotic genes alpha-smooth muscle actin, transforming growth factor-β1, matrix metallopeptidase-2 and matrix metallopeptidase-9. A contrary effect was observed in mice treated with ZnPP-IX.ConclusionsThe present study provided the evidence for the protective role of HO-1 in ameliorating MCD diet-induced fibrosing steatohepatitis. Modulation of HO-1 expression might serve as a therapeutic approach for fibrotic steatohepatitis.
Introduction:Drug-induced liver injury is a frequent cause of hepatic dysfunction. Several drugs have been identified to cause autoimmune hepatitis (AIH). Environmental chemicals are capable of triggering a certain degree of liver injury. However, toxin induced AIH is rare.Case Presentation:We reported a woman with chronic (long-term) exposures to dichlorvos, which resulted in liver injury and cirrhosis. She was diagnosed after a second liver biopsy, which was correlated with laboratory findings. At the same time, she experienced hepatic cortical blindness during her first admission.Conclusions:Chronic (long-term) exposures to dichlorvos can lead to AIH. A detailed inquiry of medical history and liver biopsy are necessary for the diagnosis of toxin-induced AIH. Corticosteroid therapy is associated with favorable evolution.
Flexure hinges are regarded as the critical components of the compliant mechanisms, its performance is one of the significant factors which could directly determine the merits and demerits of designed compliant mechanisms. So how to optimize the flexure hinges becomes the key step in designing processes of compliant mechanisms. In view of the presented importance of flexure hinges, this paper proposes a sort of multi-objective optimization method which can rapidly analyze the sensitivity and interactional laws between the performance indexes and the structural parameters of flexure hinges with the Workbench software, then to select the optimal parameters by combining with the actual working conditions of flexure hinges. Finally the finite element analysis is employed to analyze the optimization results and verify the effectiveness of proposed optimization method.
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