Cadmium-induced apoptosis of hepatocytes is not associated with death receptor-related caspase-dependent pathways in the rat

Cadmium (Cd) is a heavy metal of considerable environmental and occupational concern. The liver is the major target organ of Cd toxicity that follows from repeated exposure to Cd. The aim of this study was to investigate the mechanism of cell death of Cd-induced hepatotoxicity in a rat model. Eighteen adult male Sprague–Dawley (SD) rats were injected daily with a dose of Cd acetate (30 μM/kg body weight, subcutaneously). After 1, 2 and 7 days rats were euthanized and blood and liver tissues were sampled for analysis. Biochemical analyses of the level of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were undertaken. Histopathological and Western blot analyses for liver cellular damage and cell death were also performed. The results for the Cd-treated group of animals were compared to those from 12 control rats. The serum AST/ALT levels increased significantly 24 h after CD exposure. From the Western blot analyses, activation of Bid, independent of caspase-8 was seen and Bax induced the release of cytochrome c into the cytosol from mitochondria in a dose-dependent manner. The level of Bcl-2 was decreased. Eventually, caspase-9 and caspase-3 were activated, and poly(ADP-ribose) polymerase (PARP) was cleaved in a dose-dependent manner. A histopathological analysis and DNA fragmentation test showed apoptotic cell death of the hepatocytes increased over time. These results suggest that Cd-induced liver cell apoptosis in the rat, over a period of 7 days, may not be related to the death-receptor pathway. Moreover, apoptosis is dose-dependent and associated with the decrement of Bcl-2.     

Changes in hepatic glutathione concentration modify cadmium-induced hepatotoxicity

Cd has a strong affinity for sulfhydryl groups and is hepatotoxic. Thus, to further understand the mechanism of Cd-induced liver injury, the effect of increased and decreased hepatic glutathione (GSH) concentration on Cd-induced liver injury was examined. Liver GSH was lowered by pretreating rats with phorone (250 mg/kg, ip) or diethyl maleate (0.85 mg/kg, ip) 2 hr prior to challenge with various doses of Cd. Ten hours after Cd (1) 40–80% of the rats pretreated with phorone or diethyl maleate and challenged with 1.0–2.0 mgCd/kg died whereas no mortality was observed in the control group; (2) plasma enzyme activities of alanine (ALT) and aspartate (AST) aminotransferase and sorbitol dehydrogenase (SDH) were markedly increased in phorone and diethyl maleate-pretreated rats challenged with Cd (0.7–2.0 mg/kg) versus control rats; and (3) moderate changes in liver histology were observed in corn oil pretreated and Cd challenged rats, while prior depletion of GSH potentiated histopathologic changes in liver produced by Cd alone. Another group of rats received cysteine (1.9 g/kg, po) 3 hr prior to injection of a lethal dose of Cd. Cysteine pretreatment increased liver GSH levels by 22% 3 hr after administration and attenuated Cd-induced liver injury as evidenced by marked decreases in plasma ALT, AST, and SDH activities. Pathological changes in liver were also reduced. These data indicate that liver reduced GSH concentration is important in modulating Cd-induced hepatotoxicity.     

Nonylphenol induces apoptosis via mitochondria- and Fas-l-mediated pathways in the liver of adult male rat

Nonylphenol (NP) is an environmental contaminant known to possess estrogenic properties. Humans are constantly exposed to NP by contaminated water and food products. In the present study we sought to investigate whether treatment with low doses of NP induces apoptosis in the liver of adult rats. Rats were administered with NP by oral gavage at the doses of 15,150 and 1500 μg/kg body weight per day for 45 days. Plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were assayed. Apoptosis-related proteins namely cytochrome c, caspase-3, caspase-8, caspase-9, Fas and Fas-l, and expression of bcl-2 mRNA and bax mRNA were examined in the liver. Levels of AST and ALT were increased in the treated rats. Western blot analysis revealed elevation in the levels of cytochrome c, caspase-3, caspase-8, caspase-9, Fas and Fas-l in the liver of NP-treated rats. Decreased expression of bcl-2 mRNA (anti-apoptotic) and increased expression of bax mRNA (apoptotic) were observed in the liver of treated rats. Increased localization of caspase-3 in the hepatocytes and DNA damage were observed in the liver of treated rat. It is concluded that NP induces apoptosis in liver involving both mitochondria-dependent and Fas–Fas-l pathways and thereby, leading to hepatic damage in rats.     

iNOS-null mice are not resistant to cadmium chloride-induced hepatotoxicity

Acute administration of cadmium (Cd) to rats results in hepatotoxicity. Recent reports indicate that Kupffer cells, the resident macrophages of the liver, participate in the manifestation of Cd-induced hepatotoxicity. Nitric oxide (NO) is a reactive nitrogen radical produced by activated Kupffer cells via the induction of inducible nitric oxide synthase (iNOS). Nitric oxide can combine with superoxide to form peroxynitrite, a molecule that may participate in the toxic mechanisms of hepatotoxins, such as acetaminophen and bacterial endotoxin. It has been speculated that Cd also may exert its hepatotoxicity, in part, via the production of NO by iNOS. Therefore, this study was undertaken to determine whether iNOS contributes to Cd-induced hepatotoxicity. Wild-type (WT) mice were administered selective iNOS inhibitors (AMT and 1400W) concurrently and 3 h after administration of a hepatotoxic dose of Cd (4.0 mg Cd/mg). Additionally, WT and iNOS-null (iNOS-KO) mice were dosed iv with saline or 2.0, 2.5, 3.0, 3.5 or 4.0 mg Cd/kg. Serum alanine aminotransferase (ALT) and sorbitol dehydrogenase (SDH) activities were quantified to assess liver injury. Administration of iNOS inhibitors failed to prevent Cd-induced hepatotoxicity. Also, Cd caused a dose-dependent increase in liver injury in both WT and iNOS-KO mice. The liver injury produced by Cd in the iNOS-KO mice was not different from that in WT at any dose. These data indicate that iNOS does not appear to mediate Cd-induced hepatotoxicity.     

Tumor necrosis factor-alpha-null mice are not resistant to cadmium chloride-induced hepatotoxicity

Acute administration of cadmium results in hepatotoxicity. Recent reports indicate that Kupffer cells, the resident macrophages of the liver, participate in the manifestation of chemical-induced hepatotoxicity. Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine that is a major product of Kupffer cells and mediates the hepatotoxic effects of lipopolysaccharide (LPS). It has been speculated that cadmium also may exert its hepatotoxicity via the production of TNF-alpha by the Kupffer cells. Therefore, this study was undertaken to determine whether mice deficient in TNF-alpha are resistant to Cd-induced hepatotoxicity. TNF-alpha-null (TNF-KO) and wild-type (WT) mice were dosed ip with saline, LPS (0.1 mg/kg)/Gln (d-galactosamine, 700 mg/kg), or CdCl2 (2.2, 2.8, 3.4, and 3.9 mg Cd/kg). Serum alanine aminotransferase (ALT) and sorbitol dehydrogenase (SDH) activities were quantified to assess liver injury. Caspase-3 activity was quantified to assess hepatocellular apoptosis. LPS/Gln treatment increased ALT (17-fold) and SDH (21-fold) in WT mice. In contrast, LPS/Gln-treatment did not significantly increase ALT or SDH in TNF-KO mice. LPS/Gln-treatment caused a 7.8-fold increase in caspase-3 activity in WT mice but did not increase caspase-3 in TNF-KO mice. Cadmium caused a dose-dependent increase in liver injury in both WT and TNF-KO mice. However, the liver injury produced by Cd in the TNF-KO mice was not different from that in WT at any dose. No significant increase in caspase-3 activity was detected in any of the Cd-treated mice. These data indicate that, in contrast to LPS/Gln-induced hepatotoxicity, TNF-alpha does not appear to mediate Cd-induced hepatotoxicity.     

Effect of Picroliv on cadmium-induced hepatic and renal damage in the rat

The therapeutic efficacy of Picroliv--a standardized extract of Picrorhiza kurroa--was investigated in male rats exposed to CdCl2 (0.5 mg/kg, sc), 5 days/week for 18 weeks. Picroliv at two doses (6 and 12 mg/kg, po) was given to the cadmium (Cd)-administered group for the last 4 weeks (i.e., weeks 15-18). The Cd altered oxidative stress indices, such as increased lipid peroxidation and membrane fluidity, reduced levels of non-protein sulphydryls (NPSHs), and Na+K+ATPase activity in the liver and kidney were found close to the control values by Picroliv treatment, suggesting its antioxidant potential. The hepatoprotective action of Picroliv was evident by its ability to lower the Cd-induced liver function parameters--the serum enzymes, such as alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT) and lactate dehydrogenase (LDH). Bile flow and biliary Cd also increased as a result of Picroliv's choleretic property. The Cd-induced serum urea and urinary excretion of proteins, calcium (Ca), Cd and enzymes, such as N-acetyl-beta-D-glucosaminidase (NAG) and LDH, were less marked on Picroliv treatment, indicating recovery from nephrotoxicity. Organ uptake of Cd and essential metals by Cd exposure was reduced on Picroliv treatment. Cd-induced hepatic metallothionein (MT) was lowered by Picroliv, whereas renal MT was unaltered. Cd-induced hepatic damage was also minimized. However, the renal morphological changes were marginally protected by Picroliv. The 12-mg Picroliv dose was more effective than the 6-mg dose in causing amelioration of the above parameters. This study has provided clear evidence for the hepato- and renal protective efficacy of Picroliv against experimental Cd toxicity.     

Cadmium induces apoptotic cell death in WI 38 cells via caspase-dependent Bid cleavage and calpain-mediated mitochondrial Bax cleavage by Bcl-2-independent pathway

Previous reports have demonstrated that cadmium (Cd) may induce cell death via apoptosis, but the mechanism responsible for cellular death is not clear. In this study, we investigated the signaling pathways implicated in Cd-induced apoptosis in lung epithelial fibroblast (WI 38) cells. Apoptotic features were observed using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, propidium iodide staining and DNA laddering. A treatment of cadmium caused the caspase-8-dependent Bid cleavage, the release of cytochrome c (Cyt c), activation of caspase-9 and -3, and PARP cleavage. A caspase-8 specific inhibitor prevented the Bid cleavage, caspase-3 activation and cell death. Alternatively, we observed that full-length Bax was cleaved into 18-kDa fragment (p18/Bax); this was initiated after 12 h and by 36 h the full-length Bax protein was totally cleaved to the p18/Bax, which caused a drastic release of Cyt c from mitochondria. The p18/Bax was detected exclusively in the mitochondrial fraction, and it originated from mitochondrial full-length Bax, but not from the cytosol full-length Bax. Cd also induced the activation of the mitochondrial 30-kDa small subunit of calpain that was preceded by Bax cleavage. Cd induced the upregulation of Bcl-2 and the degradation of p53 protein. N-acetyl cysteine effectively inhibited the Cd-induced DeltaPsim reduction, indicating ROS acts upstream of mitochondrial membrane depolarization. Taken together, our results suggest that Cd-induced apoptosis was thought to be mediated at least two pathways; caspase-dependent Bid cleavage, and the other is calpain-mediated mitochondrial Bax cleavage. Moreover, we found that the function of Bid and Bax was not dependent of Bcl-2, and that ROS can also contribute in the Cd-induced cell death.     

加味大柴胡汤对梗阻性黄疸大鼠肝损伤及JNK、Bcl-2表达的影响#br#

摘要：目的　探讨加味大柴胡汤对梗阻性黄疸大鼠肝损伤及JNK、Bcl-2 mRNA和蛋白表达的影响。方法　将90只SD雄性大鼠按随机数表法分为假手术组（S组）、梗阻性黄疸组（O组）及干预组（M组）,每组30只。S组与O组每日定时生理盐水10 µL/g灌胃,M组以生药量1 g/mL的加味大柴胡汤10 µL/g灌胃,各组按时间点分别于术后3 d、7 d、10 d取材,每次每组分别随机取10只大鼠。检测各组血清天冬氨酸转氨酶（AST）、丙氨酸转氨酶（ALT）、血清总胆红素（TBIL）水平,实时荧光定量PCR（qPCR）和Western blot分别检测肝组织JNK、Bcl-2的mRNA及蛋白表达情况。结果　O组与M组血清AST、ALT、TBIL均较S组升高,且M组均低于O组（P＜0.05）。O组、M组JNK的mRNA及蛋白水平均高于S组,且M组均低于O组（P＜0.05）;O组、M组Bcl-2的mRNA及蛋白水平均低于S组（P＜0.05）,且M组均高于O组（P＜0.05）。结论　加味大柴胡汤能够改善梗阻性黄疸大鼠肝损伤,促进肝组织修复,这可能与下调JNK蛋白表达,促进Bcl-2蛋白表达,从而减弱内质网应激,抑制肝细胞的凋亡有关。     

Involvement of both intrinsic and extrinsic pathways in hepatoprotection of arjunolic acid against cadmium induced acute damage in vitro

Cadmium (Cd) is one of the ubiquitous environmental pollutants and is responsible for various organ pathophysiology including hepatic disorders. It is extremely toxic even in low concentrations and bioaccumulate in organisms. The present study has been carried out to investigate the cytoprotective role of arjunolic acid (AA), a tri terpenoid saponin, against Cd induced oxidative impairment and cell death in murine hepatocytes. Administration of cadmium (30 μM), in the form of chloride (CdCl(2)) for 2h, significantly enhanced the ALT, ALP and LDH leakage, increased reactive oxygen species (ROS) production, reduced hepatocytes viability and altered the antioxidant status of hepatocytes by reducing intracellular GSH level, anti-oxidant enzymes activity and increasing intracellular GSSG and lipid peroxidation. Evidence for Cd-induced nature of cell death was sought by flow cytometric analysis. Signal transduction studies revealed that Cd markedly increased the levels of caspase-9, -8, -3, Fas and Bid, decreased mitochondrial membrane potential, enhanced cytochrome c release in the cytosol, disturbed the Bcl-2 family protein balance, cleaved PARP protein and ultimately led to apoptotic cell death. Results showed that Cd could trigger both intrinsic and extrinsic apoptotic pathways. In addition, Cd markedly increased NF-κB nuclear translocation in association with IKKα/β phosphorylation and IκBα degradation. Simultaneous treatment with AA (200 μM), however, reduced Cd-induced oxidative stress, attenuated the nuclear translocation of NF-κB and protects the hepatocytes from Cd-induced apoptotic death. Combining, data suggest that Cd-induced hepatic dysfunction and apoptosis might be supported by the ROS formation and mediated via the activation of NF-κB. AA treatment, on the other hand, reduced Cd-induced oxidative stress, attenuated the activation of NF-κB and mitochondrion-dependent and independent apoptotic signaling pathways.     

异甘草酸镁对四氯化碳诱导肝损伤大鼠肝组织Bax、Bcl-2蛋白表达及肝纤维化指标影响

目的:观察异甘草酸镁注射液对四氯化碳诱导肝损伤大鼠肝组织Bax、Bcl-2蛋白表达及纤维化指标的影响.方法:50只大鼠随机分成正常对照组(NS组)、肝损伤模型组(MO组)、异甘草酸镁注射液高剂量组(H组)、异甘草酸镁注射液中剂量组(M组)、异甘草酸镁注射液低剂量组(L组),每组10只.MO组和各给药组大鼠将50％ CC...     

右美托咪定联合扶正化瘀方对顺铂诱导的氧化性肝损伤的保护作用

目的 探索右美托咪定(Dexmedetomidine,DEX)联合扶正化瘀方对顺铂诱导的氧化性肝损伤的保护作用机制.方法 SD大鼠腹腔注射顺铂5 mg/kg·bw的方法制备氧化性肝损伤动物体内模型,分为5组:正常组、模型组、DEX组、扶正化瘀方组和联合组(DEX和扶正化瘀方联合用药组);分别腹腔注射处理10 d,眼眶采...     

Attenuation of cadmium-induced liver injury in senescent male fischer 344 rats: role of Kupffer cells and inflammatory cytokines

In the previous study we showed that senescent male Fischer 344 rats were resistant to Cd-induced hepatotoxicity compared with young-adult rats. In the present study we investigated the role of Kupffer cells and inflammatory cytokines in this effect of aging. The phagocytic activity of Kupffer cells, determined as the removal of carbon from blood, was stimulated by the administration of a hepatotoxic dose of Cd (3 mg/kg sc) in young-adult (5 months) rats but not in old (28 months) rats. Hepatic concentrations of interleukin (IL)-1beta and cytokine-induced neutrophil chemoattractant (CINC), but not of tumor necrosis factor-alpha or IL-6, were elevated in young rats treated with Cd. In old rats, however, the increase in IL-1beta produced by Cd was not statistically significant and the increase in CINC was much lower than in young-adult rats. Pretreatment with gadolinium chloride or cyclosporin A inhibited the elevations in hepatic cytokines and attenuated Cd-induced liver damage, assessed on the basis of serum alanine aminotransferase and sorbitol dehydrogenase activities. Cd-induced hepatotoxicity in the different treatment groups correlated well with hepatic levels of CINC (r = 0.98, p < 0.001) but not with those of IL-1beta. The results suggest that (1) Kupffer cell activation is essential for inflammatory liver damage from Cd, (2) IL-1beta and CINC are important mediators of the inflammatory response induced by Cd, and (3) the attenuation of Cd-induced liver injury in senescent rats is caused by an impairment in Kupffer cell activation, leading to a lower production of CINC and less inflammatory liver injury.     

Analysis of strain difference in sensitivity to cadmium-induced hepatotoxicity in Fischer 344 and Sprague-Dawley rats.

Acute administration of cadmium (Cd) in rats results in hepatotoxicity that appears to involve the activation of Kupffer cells and the subsequent production of proinflammatory chemokines and cytokines. However, the importance of these endogenous mediators in Cd-induced hepatotoxicity is unknown. Therefore, this study was conducted to define and utilize a rat strain difference in sensitivity to Cd-induced hepatotoxicity to elucidate the role of cytokines and chemokines in Cd-induced hepatotoxicity. Doses were selected from a dose-response study of the effect of Cd on serum alanine aminotransferase (ALT) and sorbitol dehydrogenase (SDH) activities. Hepatotoxic doses of 2.0 mg Cd/kg in Fischer 344 (F344) rats and 3.0 mg Cd/kg in Sprague-Dawley (SD) rats, as well as a relatively nontoxic dose of 2.0 mg Cd/kg in SD rats, were chosen for the time-course experiment. Blood and liver from F344 (saline or 2.0 mg Cd/kg iv) and SD rats (saline or 2.0 or 3.0 mg Cd/kg iv) were collected at 0, 1, 3, 6, 10, 18, 24, and 48 h after Cd administration. Cadmium treatment caused an increase in serum ALT and SDH by 3 h and peaked between 18 and 24 h in both strains. Hepatic Cd content, metallothionein (MT) induction, and nonprotein sulfhydryl (NPSH) content were quantified and determined to be consistent with dosing rather than strain differences. Total RNA samples isolated from liver samples were analyzed for chemokine (CINC-1 and MCP-1) and cytokine (TNF-alpha, IL-1beta, IL-6, and IL-10) mRNA levels by the Quantigene branched DNA signal amplification assay. Lipopolysaccharide treatment served as a positive control for chemokine and cytokine induction. After Cd administration, F344 rat livers did not contain higher levels or earlier induction of chemokine and cytokine mRNAs than SD rats. Therefore, this study demonstrates a strain difference in sensitivity to Cd-induced hepatotoxicity that appears to be unrelated to Cd, MT, NPSH, or cytokine expression.     

Cadmium induces Ca2+-dependent necrotic cell death through calpain-triggered mitochondrial depolarization and reactive oxygen species-mediated inhibition of nuclear factor-kappaB activity

This study investigates the mechanism of cell death induced by cadmium (Cd) in Chinese hamster ovary (CHO) cells. Cells exposed to 4 microM Cd for 24 h did not show signs of apoptosis, such as DNA fragmentation and caspase-3 activation. The pro-apoptotic (Bax) or anti-apoptotic (Bcl-2 and Bcl-xL) protein levels in the Bcl-2 family were not altered. However, an increase in propidium iodide uptake and depletion of ATP, characteristics of necrotic cell death, were observed. Cd treatment increased the intracellular calcium (Ca2+) level. Removal of the Ca2+ by a chelator, BAPTA-AM, efficiently inhibited Cd-induced necrosis. The increased Ca2+ subsequently mediated calpain activation and intracellular ROS production. Calpains then triggered mitochondrial depolarization resulting in cell necrosis. Cyclosporin A, an inhibitor of mitochondrial permeability transition, recovered the membrane potential and reduced the necrotic effect. The generated ROS reduced basal NF-kappaB activity and led cells to necrosis. An increase of NF-kappaB activity by its activator, PMA, attenuated Cd-induced necrosis. Calpains and ROS act cooperatively in this process. The calpain inhibitor and the ROS scavenger synergistically inhibited Cd-induced necrosis. Results in this study suggest that Cd stimulates Ca2+-dependent necrosis in CHO cells through two separate pathways. It reduces mitochondrial membrane potential by activating calpain and inhibits NF-kappaB activity by increasing the ROS level.     

豹皮樟总黄酮对非酒精性脂肪性肝炎治疗作用及部分机制

目的研究豹皮樟总黄酮对大鼠非酒精性脂肪性肝炎(NASH)治疗作用,并初步探讨Toll样受体4(TLR4)在治疗中的作用。方法将SD大鼠随机分为5组:正常组、模型组及TFLC组(100、200、400 mg.kg-1)。除正常组外,其余各组每天给予脂肪乳剂灌胃连续10周,制备NASH模型。治疗组于造模第6周开始灌胃给予相应剂量的药物。实验10周后,检测血清ALT、AST、TC、TG、TNF-α及肝脏TC、TG含量、TLR4 mRNA和蛋白表达、NF-κB核蛋白表达,并行病理组织学检查。结果模型组大鼠血清ALT、AST、TG、TC、TNF-α水平及肝脏TC、TG含量明显升高,病理组织学检查显示模型组大鼠发生明显的肝细胞脂肪变性、炎症和坏死。TFLC能降低模型大鼠血清ALT、AST、TG、TC、TNF-α水平及肝脏TC、TG含量,病理组织学检查显示TFLC明显改善大鼠肝细胞脂肪变性及炎症程度减轻。进一步研究发现TFLC能明显抑制TLR4 mRNA和蛋白表达、NF-κB核蛋白水平。结论 TFLC对NASH有较好的治疗作用,且与抑制TLR4介导的细胞信号转导通路有关。     

美他多辛对酒精性脂肪肝大鼠CYP2E1表达的影响及其预防作用

目的探讨美他多辛对酒精性脂肪肝大鼠肝组织中CYP2E1表达的影响及其治疗酒精性脂肪肝的机制。方法 30只清洁级Wistar大鼠随机分为3组:正常组、模型组和预防组。采用乙醇(8g·kg~(-1)·d~(-1))灌胃,每日2次,间隔8h,持续8wk,建立酒精性脂肪肝动物模型。正常组:不灌服乙醇,给予等体积生理盐水;模型组:在每次灌服乙醇1h后,给予等体积灭菌注射用水;预防组:在每次灌服乙醇1h后给予美他多辛(300mg·kg~(-1)·d~(-1))。8 wk灌胃结束后,B超、HE染色和油红O染色观察脂肪肝形态变化,采用自动生化仪检测血清丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、三酰甘油(TG)、总胆固醇(TC)含量,免疫组化和蛋白印迹法检测大鼠肝组织中CYP2E1的表达。结果模型组ALT、AST、TG、TC含量明显升高,与正常组和预防组比较有显著差异(P<0.01,P<0.05),预防组明显降低CYP2E1表达与模型组比较有显著差异(P<0.01)。结论美他多辛通过抑制CYP2E1表达的上调,有效预防酒精性脂肪肝的发展。     

非酒精性脂肪性肝炎大鼠TLR4基因及其甲基化水平的相关性研究

目的 观察非酒精性脂肪性肝炎（NASH）大鼠肝脏中Toll样受体4（TLR4）基因的表达及其甲基化水平的 变化,并探讨两者在NASH发病中的相关性。方法 将20只大鼠采用随机数字表法分为正常组与模型组,每组10 只。正常组与模型组大鼠分别饲喂普通饲料和高脂高糖饲料,于24周后处死。测量大鼠体质量及肝质量,并取各组 大鼠血清及肝脏组织,于低温保存。通过病理染色观察肝细胞的形态变化、脂肪变性及炎性细胞浸润程度。采用酶 联免疫吸附测定（ELISA）法检测血清中丙氨酸转氨酶（ALT）、天冬氨酸转氨酶（AST）、三酰甘油（TG）及总胆固醇 （TC）水平;采用免疫组织化学染色法检测肝脏CD68蛋白的表达;采用蛋白免疫印迹法检测肝脏TLR4蛋白的表达; 实时荧光定量PCR检测肝脏TLR4基因mRNA的表达;亚硫酸氢测序PCR（BSP）检测肝脏TLR4基因甲基化水平。结 果 与正常组相比,模型组肝细胞体积增大,出现大量脂肪空泡,炎性细胞浸润明显;肝指数升高,血清中ALT、AST、 TC及TG明显升高（P＜0.01）;CD68蛋白的表达含量明显升高;TLR4蛋白、mRNA表达明显升高（P＜0.01）;甲基化水 平降低（P＜0.01）。TLR4的甲基化水平与其mRNA相对含量的表达呈负相关（P＜0.01）。结论 NASH模型大鼠肝 脏TLR4基因的表达与其甲基化水平呈负相关,TLR4基因甲基化水平的降低在NASH发病因素中发挥重要作用。     

葛根素对四氯化碳所诱导肝纤维化大鼠的干预作用及对TLR-4、NF-κB、AP-1的影响

目的：研究葛根素对四氯化碳所诱导肝纤维化大鼠的干预作用及其对TLR-4、NF-κB、AP-1的影响。方法：将56只SD大鼠腹腔注射四氯化碳花生油溶液（1：1）1 mL·kg^-1,每周2次,连续注射8周,建立肝纤维化大鼠模型。将经病理学检查确认成肝纤维化模型的大鼠随机分为5组：模型组、阳性药水飞蓟素40 mg·kg^-1组、葛根素20,40,80 mg·kg^-1组,每组10只。每日灌胃给药一次,连续给药60 d。同时另设置正常组大鼠10只。Masson染色法观察各组肝组织病理学变化和纤维化程度。末次给药12 h后,检测大鼠血清谷草转氨酶（AST）、丙氨酸转氨酶（ALT）、白介素-6（IL-6）的水平;Elisa法检测肝组织中肿瘤坏死因子-α（TNF-α）、白介素-1（IL-1）的含量;蛋白免疫印迹法检测肝组织中TLR-4、NF-κB、AP-1的蛋白表达。结果：与模型相比,葛根素可降低肝纤维化大鼠血清AST、ALT、IL-6的水平以及TNF-α、IL-6的含量（P<0.05）,并明显下调TLR-4、NF-κB、AP-1的蛋白表达水平（P<0.05）。结论：葛根素具有一定的抗肝纤维化作用,其作用机制可能与调节肝组织中TLR-4、NF-κB、AP-1的蛋白水平有关。     

低聚原花青素对大鼠肝纤维化氧化损伤的影响

目的 研究低聚原花青素抗肝纤维化的作用及机制.方法 SD大鼠随机分为正常对照组、模型组、扶正化瘀胶囊组、低聚原花青素低、中、高剂量组(60、120、240 mg·kg-1).采用腹腔注射四氯化碳(CCl4)构建肝纤维化模型,采用苏木精-伊红(HE)染色法进行肝脏病理学观察.生化检测血清丙氨酸转移酶(ALT)和天冬氨酸转移酶(AST),酶联免疫吸附(ELISA)法测定肝组织的超氧化物歧化酶(SOD)和丙二醛(MDA)含量.蛋白质免疫印迹法检测沉默信息调节因子1(SIRT1)和Nrf2蛋白表达.结果 低聚原花青素(60、120、240 mg·kg-1)组显著抑制四氯化碳诱导的大鼠肝纤维化程度,血清丙氨酸转移酶、天冬氨酸转移酶水平及肝脏组织中丙二醛水平明显降低,超氧化物歧化酶显著提高,并上调沉默信息调节因子1和Nrf2蛋白表达.结论 低聚原花青素具有抗纤维化的作用,其作用机制可能与其抗氧化作用并上调沉默信息调节因子1和Nrf2蛋白表达有关.