El-Agamy Dina S, Almaramhy Hamdi H, Ahmed Nishat, Bojan Bsmah, Alrohily Waad D, Elkablawy Mohamed A
Department of Pharmacology and Toxicology, College of Pharmacy, Taibah University, Al-Madinah Al-Munawwarah, Saudi Arabia.
Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.
Cell Physiol Biochem. 2018;47(2):523-534. doi: 10.1159/000489986. Epub 2018 May 23.
BACKGROUND/AIMS: Phosphodiesterase-5 inhibitors have beneficial effects in multiple liver diseases possibly through the reduction of oxidative stress and inflammatory response. However, these effects have not yet been examined in cholestatic liver dysfunction. Hence, this study aimed to explore the ability of vardenafil, a known phosphodiesterase-5 inhibitor, to repress lithocholic acid (LCA)-induced cholestatic liver injury and investigate the possible molecular pathways.
Male Swiss albino mice were treated with LCA (0.125 mg/g) twice daily for 7 days to induce cholestatic liver damage. Vardenafil was administered 3 days before and throughout the administration of LCA. Serum markers of hepatotoxicity and hepatic nitro-oxidative stress along with antioxidant parameters were measured, and the histopathology of liver tissues was assessed. The expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its target genes was examined using PCR. The activation of nuclear factor kappa-B (NF-κB) and the levels of inflammatory cytokines were determined. NLRP3 inflammasome and its components were studied by PCR and western blot.
LCA induced marked cholestatic liver damage as demonstrated by increased serum transaminases, alkaline phosphatase (ALP), lactate dehydrogenase (LDH), bilirubin, and bile acids. Examination of liver specimens confirmed the biochemical results. Nitro-oxidative stress parameters were significantly elevated along with reduced antioxidant capacity in hepatic tissue following LCA administration. LCA suppressed Nrf2 and its target genes and decreased the mRNA expression and binding capacity of Nrf2 as well as the mRNA expression of GCLm, GCLc, Nqo1, and HO-1. Additionally, LCA enhanced the activation of NF-κB, which was accompanied by elevations of inflammatory cytokines. Importantly, LCA induced the activation of NLRP3 inflammasome. LCA increased the expression of NLRP3, ASC, caspase-1, and IL-1β genes and proteins in hepatic tissue. The activities of IL-1β and caspase-1 were increased in the LCA group. Interestingly, vardenafil ameliorated LCA-induced hepatic injury and alleviated all biochemical, histopathological, and inflammatory parameters.
These data elucidated the effects of Nrf2 inhibition and NLRP3 inflammasome activation in LCA-induced liver injury. The hepatoprotective activity of vardenafil in LCA-induced cholestatic damage may result from the drug's ability to activate Nrf2 signaling and prevent the activation of NLRP3, which could suppress the inflammatory responses in hepatic tissue. Thus, vardenafil can be considered a novel anti-inflammatory remedy for cholestatic liver damage.
背景/目的：磷酸二酯酶-5抑制剂可能通过减轻氧化应激和炎症反应，对多种肝脏疾病产生有益作用。然而，这些作用尚未在胆汁淤积性肝功能障碍中得到研究。因此，本研究旨在探讨已知的磷酸二酯酶-5抑制剂伐地那非抑制石胆酸（LCA）诱导的胆汁淤积性肝损伤的能力，并研究可能的分子途径。
雄性瑞士白化小鼠每天两次接受LCA（0.125mg/g）处理，持续7天以诱导胆汁淤积性肝损伤。在给予LCA前3天及整个给药期间给予伐地那非。检测肝毒性血清标志物、肝脏硝基氧化应激以及抗氧化参数，并评估肝组织的组织病理学。使用PCR检测核因子红细胞2相关因子2（Nrf2）及其靶基因的表达。测定核因子κB（NF-κB）的激活情况以及炎症细胞因子水平。通过PCR和蛋白质印迹研究NLRP3炎性小体及其成分。
LCA诱导了明显的胆汁淤积性肝损伤，表现为血清转氨酶、碱性磷酸酶（ALP）、乳酸脱氢酶（LDH）、胆红素和胆汁酸升高。肝组织标本检查证实了生化结果。给予LCA后，肝脏组织中的硝基氧化应激参数显著升高，同时抗氧化能力降低。LCA抑制Nrf2及其靶基因，降低Nrf2的mRNA表达和结合能力以及GCLm、GCLc、Nqo1和HO-1的mRNA表达。此外，LCA增强了NF-κB的激活，同时伴有炎症细胞因子升高。重要的是，LCA诱导了NLRP3炎性小体的激活。LCA增加了肝脏组织中NLRP3、ASC、caspase-1和IL-1β基因及蛋白的表达。LCA组中IL-1β和caspase-1的活性增加。有趣的是，伐地那非改善了LCA诱导的肝损伤，并减轻了所有生化、组织病理学和炎症参数。
这些数据阐明了Nrf2抑制和NLRP3炎性小体激活在LCA诱导的肝损伤中的作用。伐地那非在LCA诱导的胆汁淤积性损伤中的肝保护活性可能源于该药物激活Nrf2信号传导并阻止NLRP3激活的能力，这可能抑制肝脏组织中的炎症反应。因此，伐地那非可被视为胆汁淤积性肝损伤的一种新型抗炎药物。
