Mouse liver regeneration after carbon tetrachloride injury as test system for hepatic growth regulators

A test system for growth regulators based on the time course of liver regeneration in male NMRI mice injected intraperitonelly (ip) with 50 nmol CC1₄ at 12 is described. Regenerative DNA synthesis (labelling index) peaked at 36 h after CC1₄ injury, and the Colcemid-assessed mitotic rate (MR) at 42 h, i.e., 6 h later. This response pattern was used to assess the effects of factors in liver extracts that regulate or modulate hepatocyte proliferation. The effect of one, two, four or eight ip injections of an aqueous mouse liver extract on MR was tested at 48 h. A 30–70% inhibition was seen only after single injections at 12 h, 29 h or 44 h after CCl₄ treatment. A 30–80% stimulation was observed after a single injection of the liver extract at 0, 5 or 24 h, and after two or four injections. The assay system could thus detect the presence of growth modulators in the extract. The experiments also showed that the timing was crucial. We recently isolated and characterized a growth inhibitory pentapeptide from mouse liver extracts. Using a synthetic pentapeptide with the same structure we reassessed the timing for growth inhibition seen with the liver extract. The following test system for growth inhibitors seemed most expedient: inhibitor administration at 29 h to affect G₁-S transition, measured as reduced DNA synthesis at 36 h, or inhibitor administration at 44 h to affect G₂-M transition, measured as reduced MR at 48 h.     

FGF21 alleviates acute liver injury by inducing the SIRT1‐autophagy signalling pathway

Liver injury can lead to different hepatic diseases, which are the mainly causes of high global mortality and morbidity. Autophagy and Sirtuin type 1 (SIRT1) have been shown protective effects in response to liver injury. Previous studies have showed that Fibroblast growth factor 21 (FGF21) could alleviate acute liver injury (ALI), but the mechanism remains unclear. Here, we verified the relationship among FGF21, autophagy and SIRT1 in carbon tetrachloride (CCl₄)‐induced ALI. We established CCl₄‐induced ALI models in C57BL/6 mice and the L02 cell line. The results showed that FGF21 was robustly induced in response to stress during the development of ALI. After exogenous FGF21 treatment in ALI models, liver damage in ALI mice was significantly reduced, as well as serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Consistently, FGF21 also greatly reduced the levels of ALT, AST, pro‐inflammatory cytokines interleukin 6 (IL6) and tumour necrosis factor‐alpha (TNFα) in ALI cell lines. Mechanistically, exogenous FGF21 treatment efficiently upregulated the expression of autophagy marker microtubule‐associated protein light chain‐3 beta (LC3 II) and autophagy key molecule coiled‐coil myosin‐like BCL2‐interacting protein (Beclin1), which was accompanied by alleviating hepatotoxicity in CCl₄‐treated wild‐type mice. Then, we examined how FGF21 induced autophagy expression and found that SIRT1 was also upregulated by FGF21 treatment. To further verify our results, we constructed an anti‐SIRT1 lentit‐RNAi to inhibit SIRT1 expression in mice and L02 cells, which reversed the protective effect of FGF21 on ALI. In summary, these results indicate that FGF21 alleviates ALI by enhancing SIRT1‐mediated autophagy.     

Chicoric acid ameliorate inflammation and oxidative stress in Lipopolysaccharide and d-galactosamine induced acute liver injury

Chicoric acid is polyphenol of natural plant and has a variety of bioactivity. Caused by various kinds of stimulating factors, acute liver injury has high fatality rate. The effect of chicoric acid in acute liver injury induced by Lipopolysaccharide (LPS) and d -galactosamine (d -GalN) was investigated in this study. The results showed that CA decreased the aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum and reduced the mortality induced by LPS/d -GalN. CA can restrain mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) to alleviate inflammation. Meanwhile, the results indicated CA can active nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway with increasing the level of AMP-activated protein kinase (AMPK). And with the treatment of CA, protein levels of autophagy genes were obvious improved. The results of experiments indicate that CA has protective effect in liver injury, and the activation of AMPK and autophagy may make sense.     

Corynoline protects against zearalenone-induced liver injury by activating the SIRT1/Nrf2 signaling pathway

Corynoline has been reported to have anti-inflammatory and antioxidative effects. In the present study, the potential protective effects of corynoline against zearalenone (ZEA)-induced liver injury were investigated. ZEA was administered daily for 5 days. Then, liver tissues were used for subsequent experiments. Corynoline attenuated liver histopathological changes induced by ZEA. The production of tumor necrosis factor-α and interleukin-1β in liver tissues, as well as aspartate aminotransferase and alanine aminotransferase in serum, was also inhibited by corynoline. Meanwhile, ZEA-induced MPO activity and MDA content were both attenuated by corynoline. ZEA-induced NF-κB p65 and IκBα phosphorylation were inhibited by corynoline. Furthermore, SIRT1, Nrf2, and HO-1 expression were increased by corynoline. In addition, the protective effects of corynoline against liver injury were reversed by the SIRT1 inhibitor EX-527. Taken together, corynoline protected against ZEA-induced liver injury by activating the SIRT1/Nrf2 signaling pathway.     

外源性硫化氢对大鼠内毒素性肺损伤的影响及机制研究

目的：应用H2S供体硫氢化钠（NaHS）,观察外源性H2S对中性粒细胞（PMN）在脂多糖（LPS）刺激大鼠肺内聚集的影响及其机制。方法：采用尾静脉注射致Sprague-Dawley（SD）大鼠内毒素急性肺损伤（ALI）模型,将大鼠随机分为4组（n=8～12）。对照组：由尾静脉注射无菌生理盐水（0.5ml/kg）;LPS组：由尾静脉注射LPS（1mg/kg）;LPS＋NaHS组：注射LPS前10min腹腔注射NaHS（28μmol/kg）;NaHS组：腹腔注射NaHS（28μmol/kg）。6h后光镜下观察各组大鼠肺组织学变化并计数肺泡间隔中PMN数目（number/HP）;脱氧核苷酸末端转移酶介导的原位末端标记技术（TUNEL）测定支气管肺泡灌洗液（BALF）中PMN凋亡百分率及应用Western blot检测肺组织细胞间黏附分子（ICAM）-1和核转录因子（NF）-κB表达的变化。结果：注射LPS后动物肺组织出现出血、水肿及PMN聚集等病理征象。LPS组大鼠肺组织中PMN数目较对照组显著增加,PMN凋亡百分率下降,ICAM-1、NF-κB表达显著增高;应用NaHS后每高倍镜PMN数目显著减少,PMN凋亡百分率明显增高,ICAM-1、NF-κB表达显著降低,肺组织损伤减轻。单独应用NaHS组大鼠上述各项指标与对照组大鼠相比无显著差异。结论：NaHS可减少PMN在肺内聚集,其机制与其抑制NF-κB通路,从而下调ICAM-1表达、促进PMN凋亡有关。     

4-羟基苯并恶唑-2-酮对四氯化碳致小鼠急性肝损伤保护作用

日的研究4一羟基苯并恶唑-2-酮（4-hydroxy-2-benzoxazolone,HBOA）对四氯化碳所致小鼠急性肝损伤的保护作用,并探讨其疗效机制。方法采用腹腔注射四氯化碳（carbonte trachloride,cch）制备小鼠急性肝损伤模型,HBOA灌胃给药,检测小鼠血清中的乳酸脱氢酶（LDH）活性以及肝组织中过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GSH-Px）含量,并用免疫组化法观察肿瘤坏死因子（TNF-a）的表达情况。结果HBOA能明显降低CCh致急性肝损伤小鼠血清LDH活性,同时升高肝组织中CAT、GSH-Px的活性并降低肝组织中TNF-a的表达。结论HBOA对CCh所致小鼠急性肝损伤有一定的保护作用。     

牛磺酸对肢体缺血／再灌注后肝损伤大鼠TNF-α、NF-κB表达的影响

目的：探讨给予牛磺酸预处理对肢体缺血／再灌注（limb ischemia-reperfusion,H／R）后大鼠肝脏损伤及,INn、NF—KB表达的影响及意义。方法：采用Wistar大鼠建立LI/R损伤模型,随机分为4组（n=10）：对照（C）组,缺血／再灌注（I／R）组,牛磺酸（T）组和牛磺酸＋缺血／再灌注（TR）组。比色法测定动物血浆ALT、AST、MDA,肝组织MDA、MPO、DNA裂解率和钙含量,放免法检测血浆及肝组织TNF-α水平;HE染色观察肝脏组织形态改变;免疫组化法观察NF-κB蛋白表达。结果：与C组比较,I／R和TR组各损伤性指标、TNF-α水平均升高,NF-κB蛋白表达增高（P〈0．01）;但TR组上述各项指标较I／R组显著降低。结论：牛磺酸预处理可减轻大鼠LI／R所致肝脏损伤,降低TNF-α、NF-κB表达。     

褪黑素对油酸致大鼠急性肺损伤的防护作用及其机制研究

目的：研究油酸（OA）致大鼠急性肺损伤（ALI）时,P-选择素（Ps）、细胞间粘附分子-1（ICAM-1）和核因子-κB（NF-KB）在肺组织中的表达及褪黑素（MT）对肺组织的保护作用及其机制。方法：将48只SD大鼠随机分为4组（n=12）,对照组（Control）、油酸组（OA）、MT＋OA组,SB203580＋OA组。采用尾静脉注射油酸的方法建立大鼠Au的模型,测定肺系数,光镜下观察大鼠肺组织形态学改变,并通过免疫组织化学染色技术观察肺组织中Ps、ICAM-1和NF-κB的表达变化。结果：与control组相比,OA组大鼠肺系数明显升高（P〈0．05）;肺组织损伤严重,肺泡间隔明显增宽,肺泡腔及肺间质弥漫性炎细胞浸润;Ps、ICAM-1和NF-κB的阳性表达信号明显增强（P〈0．05）;应用MT和SB203580均显著缓解上述变化（P〈0．05）。结论：MT对ALI时的肺组织起明显的保护作用,其保护机制可能与抑制Ps、ICAM-1和NF-κB的表达有关。     

粒细胞集落刺激因子对小鼠内毒素性急性肝损伤的保护作用

目的观察粒细胞集落刺激因子对小鼠内毒素性急性肝损伤的作用,并对其机制进行初步探讨。方法昆明（KM）小鼠随机分为模型组、预防组和正常组,模型组小鼠腹腔注射内毒素（LPS）10mg／kg或30mg／kg,预防组于造模前1小时皮下注射重组人粒细胞集落刺激因子（rhG-CSF）500btg／kg,正常组注射等剂量的生理盐水,观察各组小鼠的存活率及造模后6h、24h小鼠肝脏组织病理变化,全自动生化分析仪检测血清丙氨酸氨基转移酶（ALT）和天门冬氨酸氨基转移酶（AsT）的水平,酶联免疫吸附试验（ELISA）检测血清肿瘤坏死因子（TNF—a）和白介素10（IL-10）的水平。结果预防组小鼠存活率与模型组相比无明显差异（80％VS66．7％,P〉0．05）;预防组肝组织损伤及肝功能酶学指标ALT和AST均好于模型组（P〈0．05）;预防组小鼠血清IL-10的表达水平在6小时点明显高于模型组（P〈0．05）,24小时点与模型组相比无明显差异（P〉0．05）,血清TNF-a表达水平与模型组相比差异无统计学意义（P〉0．05）。结论粒细胞集落刺激因子对小鼠内毒素性急性肝损伤具有保护作用,对小鼠的存活率无明显影响。     

Metabolomics and biomarker discovery: NMR spectral data of urine and hepatotoxicity by carbon tetrachloride, acetaminophen, and d-galactosamine in rats

The primary objective of this study was to discover biomarkers which are correlated with hepatotoxicity induced by chemicals using ¹H NMR spectral data of urine. A procedure of nuclear magnetic resonance (NMR) urinalysis using pattern recognition was proposed for early screening of the hepatotoxicity of CCl₄, acetaminophen (AAP), and d-galactosamine (GalN) in rats. The hepatotoxic compounds were expected to induce necrosis in hepatocytes. This was confirmed through blood biochemistry and histopathology. CCl₄ (1 ml/kg, po) or GalN (0.8 g/kg, ip) was single administered to Sprague–Dawley (S–D) rats and urine was collected every 24 h. Animals were sacrificed 24 h or 48 h post-dosing. AAP (2 g/kg, po) was administered for 2 days and then the animals were sacrificed 24 h after the last treatment. NMR spectroscopy revealed evidently different clustering between control groups and hepatotoxicant treatment groups in global metabolic profilings as indicated by partial least square (PLS)-discrimination analysis (DA). In targeted profilings, endogenous metabolites of allantoin, citrate, taurine, 2-oxoglutarate, acetate, lactate, phenylacetyl glycine, succinate, phenylacetate, 1-methylnicotinamide, hippurate, and benzoate were selected as putative biomarkers for hepatoxicity by CCl₄, AAP, and GalN. Comparison of our rat ¹H NMR PLS-DA data with histopathological changes suggests that ¹H NMR urinalysis can be used to predict hepatotoxicity induced by CCl₄, AAP, and GalN.     

髓过氧化物酶与大剂量顺铂所致小鼠肝功能变化关系的探讨

目的利用大剂量顺铂（Cisplatin,DDP）诱发小鼠急性肾功能衰竭的动物模型,了解大剂量DDP在引起肾损伤的同时对小鼠肝的毒性作用,探讨髓过氧化物酶（Peroxidase,MPO）与DDP所致小鼠肝功能变化的关系。方法 C57BL/6小鼠50只,雌雄各半,依体重随机分为DDP用药组和生理盐水（NS）对照组。15 mg/kg DDP单次腹腔内注射,等量NS对照。分别取对照组小鼠和DDP用药后6、12、24和48 h小鼠各10只,称重后乙醚麻醉,内眦静脉取血检测肝、肾功能;剖腹取肝、称重、计算肝系数,并取少量肝组织行HE染色、形态学观察;检测血浆和肝组织匀浆中MPO活性,统计学分析。结果大剂量DDP用药后48 h,小鼠出现急性肾功能衰竭。DDP用药后6 h血清谷丙转氨酶（ALT）含量达（91.0±11.3）IU/L,与对照组比较差异有统计学意义（P〈0.05）,随后血清ALT含量持续维持在高水平。DDP用药后各组小鼠肝系数明显升高,光镜下见肝细胞广泛变性水肿,肝小叶中可见点状坏死及炎细胞浸润。DDP用药后6 h,小鼠肝组织匀浆MPO含量显著升高,达（1.54±0.45）U/g,与对照组（0.58±0.28）U/g差异有统计学意义（P〈0.01）,随后MPO含量降至正常水平;DDP用药后小鼠外周血MPO含量缓慢增高,用药后48 h达（12.78±2.78）U/L,与对照组（8.06±1.89）U/L比较差异有统计学意义（P〈0.05）。结论大剂量DDP在诱发小鼠急性肾功能衰竭的同时还可引起小鼠急性肝细胞的破坏,其发生可能与肝组织内白细胞的激活及MPO的释放有关。     

MicroRNA-449b-5p targets HMGB1 to attenuate hepatocyte injury in liver ischemia and reperfusion

MicroRNAs (miRNAs) participate in the pathological process of liver ischemia/reperfusion (I/R) injury. MiR-449b-5p is the target miRNA of high mobility group box 1 (HMGB1). Its role and molecular mechanism in liver I/R injury remain unidentified. In this study, we found a protective effect of miR-449b-5p against hepatic I/R injury. HMGB1 expression significantly increased, whereas miR-449b-5p dramatically decreased in patients after liver transplant and in L02 cells exposed to hypoxia/reoxygenation (H/R). A dual-luciferase reporter assay confirmed the direct interaction between miR-449b-5p and the 3′ untranslated region of HMGB1 messenger RNA. We also found that overexpression of miR-449b-5p significantly promoted cell viability and inhibited cell apoptosis of L02 cells exposed to H/R. Moreover, miR-449b-5p repressed HMGB1 protein expression and nuclear factor-κB (NF-κB) pathway activation in these L02 cells. In an in vivo rat model of hepatic I/R injury, overexpression of miR-449b-5p significantly decreased alanine aminotransferase and aspartate aminotransferase and inhibited the HMGB1/NF-κB pathway. Our study thus suggests that miR-449b-5p alleviated hepatic I/R injury by targeting HMGB1 and deactivating the NF-κB pathway, which may provide a novel and promising therapeutic target for hepatic I/R injury.     

Differential regulation of IGF-II-induced IL-8 by extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinases in human keratinocytes

In order to study the relationship between insulin like growth factor-II (IGF-II) and interleukin-8 (IL-8) that are upregulated in psoriasis, we monitored IL-8 expression in IGF-II-treated human keratinocytes and explored the signaling pathways of IL-8 expression by IGF-II. IGF-II increased the IL-8 mRNA and protein levels in human keratinocytes. The upregulation of IL-8 expression by IGF-II was reduced by pretreatment with inhibitors of tyrosine kinase, Src, PI3-kinase, and ERK, but not by p38. Furthermore, IGF-II remarkably increased the DNA binding activities of NF-kappaB and AP-1, and the IL-8 promoter activity. However, cotransfection with IkappaB mutant blocked the IGF-II-induced IL-8 promoter activity. In addition, cotransfection with dominant negative MEK1 mutant, but not with dominant negative p38 mutant, blocked the IGF-II-induced IL-8 promoter activity. These results suggest that IGF-II is involved in the pathogenesis of psoriasis by inducing IL-8 gene expression through the tyrosine kinase-Src-ERK1/2-AP-1 pathway, and the PI3-kinase and NF-kappaB pathway.     

Dexmedetomidine attenuates lipopolysaccharide-induced acute liver injury in rats by inhibiting caveolin-1 downstream signaling pathway

Objective: The aim of the present study is to investigate the anti-injury and anti-inflammatory effects of dexmedetomidine (Dex) in acute liver injury induced by lipopolysaccharide (LPS) in Sprague–Dawley rats and its possible mechanism.Methods: The acute liver injury model of male rats was established by injecting LPS into tail vein. The mean arterial pressure (MAP) of rats was recorded at 0–7 h, and lactic acid was detected at different time points. Wet/dry weight ratio (W/D) was calculated. Pathological changes of rat liver were observed by HE staining. ALT and AST levels in serum were detected. The activities of myeloperoxidase (MPO) and superoxide dismutase (SOD) in liver tissue homogenate and the levels of IL-1β and IL-18 in serum were detected by ELISA. Protein levels of Caveolin-1 (Cav-1), TLR-4 and NLRP3 in liver tissue were tested by immunohistochemistry method. The expression of Cav-1, TLR-4 and NLRP3 mRNA in liver tissue was detected by quantitative polymerase chain reaction (qPCR) to explore its related mechanism.Results: Compared with NS group, serum lactic acid, W/D of liver tissue, MPO, SOD, IL-1β and IL-18 were significantly increased and MAP decreased significantly in LPS group and D+L group. However, compared with NS group, D group showed no significant difference in various indicators. Compared with LPS group, MPO, SOD, IL-1β and IL-18 were significantly decreased and MAP was significantly increased in D+L group. D+L group could significantly increase the level of Cav-1 protein and decrease the level of TLR-4 and NLRP3 protein in liver tissue caused by sepsis. The expression of Cav-1 mRNA was significantly up-regulated and the expression of TLR-4 and NLRP3 mRNA was inhibited in D+L group.Conclusion: Dex pretreatment protects against LPS-induced actue liver injury via inhibiting the activation of the NLRP3 signaling pathway by up-regulating the expression of Cav-1 by sepsis.     

维生素K2对四氯化碳诱导的急性大鼠肝损伤的保护作用

探讨枯草芽胞杆菌产物维生素K2(MK-7)对四氯化碳诱导的急性肝损伤的保护作用及机制。

选取SPF级实验用6~8周龄SD雄性大鼠30只, 体质量200~220 g, 随机分为5组(每组6只): 空白组、肝损伤模型组、模型+溶剂组、模型+水飞蓟素组和模型+维生素K2组。空白组不做额外处理, 其余各组均予四氯化碳染毒, 溶剂组给予与维生素K2组相同体积的大豆油, 水飞蓟素组添加水飞蓟素100 mg/100 g体质量, 维生素K2组用维生素K2每日灌胃(给药剂量为2 μg/100 g体质量)。1周后观察大鼠体征和肝脏外观、肝脏炎症及微肉芽肿、肝细胞空泡化结构, 检测血液AST、ALT、MDA、SOD、TNF-α和IL-6含量。

与肝损伤模型组大鼠比, 模型+维生素K2组肝脏指数下降(t=3.250 0, P=0.031 4)。HE染色结果显示, 与肝损伤模型组大鼠比, 模型+维生素K2组空泡化程度明显降低, 损伤较为弥散。与肝损伤模型组大鼠比, 模型+维生素K2组肝功、氧化应激指标及相关炎症因子水平降低[AST(t=4.283 0, P=0.012 8)、ALT(t=2.582 0, P=0.041 6)、MDA(t=7.028 0, P=0.005 9)、SOD(t=3.384 0, P=0.011 7)、TNF-α(t=3.459 0, P=0.013 5)、IL-6(t=2.422 0, P=0.041 8)]。

维生素K2可减轻大鼠急性肝损伤程度, 其作用可通过改善抗氧化酶体系、抑制氧化应激反应及降低炎性因子水平而实现。