TGF-β1和TGF-βⅡ型受体酵母表达载体构建

  目的  研究截短型人肝细胞生长因子突变体（tvNK1）对转化生长因子β1（TGF-β1）诱导人肝星状细胞LX-2纤维化的影响。  方法  把经PCR和双酶切的小分子泛素相关修饰蛋白（SUMO）和tvNK1的融合基因SUMO-tvNK1插入原核表达载体pET28a,诱导表达和Ni²⁺亲和层析纯化SUMO-tvNK1;进一步经SUMO蛋白酶Ulp1水解和Ni²⁺亲和层析纯化tvNK1,MTT法观察其对TGF-β1诱导LX-2纤维化细胞增殖的影响,qPCR及蛋白印迹（WB）检测其对I型胶原蛋白（col1α1）和α – 平滑肌球蛋白（α-SMA）蛋白表达的影响。  结果  宿主菌Rosetta/pET28a-SUMO-tvNK1在37 ℃经1 mmol/L IPTG诱导5 h获得SUMO-tvNK1的可溶性表达,将超声破碎后上清液经Ni²⁺亲和层析成功获得SUMO-tvNK1,进一步经Ulp1水解和Ni²⁺亲和层析纯化tvNK1,SDS-PAGE鉴定其分子量约为22.0 kDa,MTT显示20和40 ng/mL的tvNK1能明显抑制TGF-β1活化的人肝星状细胞LX-2增殖,qPCR及WB显示20和40 ng/mL的tvNK1能显著抑制活化的LX-2细胞中Col1α1和 α-SMA在mRNA和蛋白水平表达。  结论  SUMO蛋白可用于制备tvNK1,其能抑制TGF-β1活化的LX-2细胞增殖并具有抗纤维化作用,为进一步体内外功能研究打下基础。     

肝星形细胞激活的转录调节

肝星形细胞(HSC)被认为是肝纤维化的关键成分,因此了解启动和持续HSC激活的分子机制有重 要意义。基因转录水平的HSC激活需要同时激活几种HSC基因组的关键转录调节者。现综述调节激活HSC的几 种转录因子。     

硫普罗宁注射液干预大鼠肝星状细胞致肝纤维化形成作用的研究

目的 探讨硫普罗宁注射液抗肝纤维化的作用及其机制。方法 肝星状细胞的分离采用胶原酶循环灌流法。硫普罗宁注射液（25mg／ml、50mg／ml、100mg／ml、200mg／ml、400mg／ml）作用不同时间（24h、48h、72h）后，采用MTT法OD值检测细胞活化增殖情况。硫普罗宁注射液（200mg／m1）作用24h和48h后，流式细胞术检测细胞增殖周期。采用溴乙锭／吖啶橙荧光染色法结合显微镜下形态学观察及流式细胞术检测硫普罗宁注射液对活化的肝星状细胞凋亡的影响。结果 硫普罗宁注射液各浓度组OD值较对照组明显降低（P〈0.05），硫普罗宁注射液200mg／ml组作用24h和48h流式细胞术检测出C2-M期的细胞数均明显高于正常对照组（P〈0．01），硫普罗宁注射液各浓度组荧光染色法和流式细胞术均未检测到肝星状细胞凋亡。结论 硫普罗宁注射液主要是通过抑制肝星状细胞增殖的C2-M期而产生抗肝纤维化作用的。     

Antiproliferative and proapoptotic activity of Turkish propolis on human lung cancer cell line

Cancer is a heterogeneous disease, two of whose characteristic features are uncontrollable cell proliferation and insufficient apoptosis. Various studies have investigated the antiproliferative effects of propolis, a natural bee product, from different countries, and its cytotoxic effects have been attributed to its polyphenol contents. The purpose of this study was to show the cytotoxic effects, and possible mechanisms involved, of ethanolic extract of Turkish propolis (EEP) on the human lung cancer (A549) cell line. Cytotoxic activity of EEP on A549 cells was revealed using the MTT assay. Mechanisms involved in the cytotoxic action of EEP on A549 cells were then investigated in terms of apoptosis, mitochondrial membrane potential and cell cycle using flow cytometry, endoplasmic reticulum stress using RT-PCR, and caspase activity using luminometric analysis. EEP exhibited selective toxicity against A549 cells compared to normal fibroblast cells. We determined that EEP arrested the cell cycle of A549 cells at the G₁ phase, induced endoplasmic reticulum stress, caspase activity, and apoptosis and reduced mitochondrial membrane potential. These results indicate that Turkish propolis is capable of reducing cancer cell proliferation and may have a promising role to play in the development of new anticancer drugs in the future.     

Prevention of rat hepatocarcinogenesis by acyclic retinoid is accompanied by reduction in emergence of both TGF-alpha-expressing oval-like cells and activated hepatic stellate cells

We investigated the preventive effects of a synthetic acyclic retinoid, NIK-333, on the early and late events of hepatocarcinogenesis in male F344 rats treated with 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB). NIK-333 was administered once a day on consecutive days at a dose of 10, 40, or 80 mg/kg body weight along with the supplementation with 3'-MeDAB-containing diet for 16 wk. Animals from each group were sacrificed at 4 and 16 wk after the commencement of the experiment to determine the effect of NIK-333 on the early and late stages of carcinogenesis, respectively. NIK-333 suppressed the emergence of both oval-like cells expressing transforming growth factor (TGF)-alpha, putative progenitors of hepatocellular carcinoma (HCC), and activated hepatic stellate cells, major matrix-producing cells of the liver, in the early stage and inhibited the incidence of HCC in the late phase. These results suggest that NIK-333 is a promising drug for the chemoprevention of HCC by uniquely suppressing the early events of hepatocarcinogenesis, that is, development of both oval-like cells and fibrogenesis.     

口山酮抑制肝星状细胞活化作用及其机制研究

目的研究去甲基雏菊叶龙胆酮（DMB）对肝星状细胞（HSC）活化的影响及其机制。方法培养大鼠肝星状细胞株HSC-T6,分别加入1、3或10μM DMB孵育12-48 h。细胞组织化学检测α-平滑肌肌动蛋白（α-SMA）表达;酶联免疫吸附试验测定I型胶原的合成;逆转录PCR检测转化生长因子-β1（TGF-β1）和结缔组织生长因子（CTGF）mRNA水平。结果体外培养的HSC-T6表现为激活状态,表达α-SMA和合成I型胶原。处理DMB能显著降低体外培养的HSC-T6表达α-SMA细胞数目和I型胶原的合成,且呈浓度依赖性。而且,DMB能浓度依赖性降低HSC TGF-β1和CTGF mRNA水平。结论DMB能抑制HSC的活化,其作用与抑制TGF-β1-CTGF促纤维化通路有关。     

小鼠肝星状细胞分离与鉴定

目的 探讨小鼠肝星状细胞的分离、培养方法,提高其分离效率.方法 取体重约30 g的雄性ICR小鼠,用Ⅳ型胶原酶、Dnase Ⅰ进行体内门静脉灌注消化小鼠肝脏细胞,经过Percoll不连续密度梯度离心法分离小鼠肝星状细胞.台盼蓝拒染方法鉴定细胞存活率,紫外激发下观察自发荧光,油红O染色和结蛋白细胞免疫荧光染色鉴定细胞.结果 小鼠肝星状细胞得率为6.5×105/只,存活率在91％以上,纯度大于92％.结论 该实验建立了简便而有效的小鼠肝星状细胞分离与鉴定方法.     

四氯化碳对体外培养肝星状细胞钙浓度的影响

目的研究四氯化碳(CC l4)对肝星状细胞内游离Ca2 ([Ca2 ]i)的影响。方法用常规的细胞培养方法,每组加入5~15 mmol/L的CC l4处理细胞,分别作用2~8 h后,以F luo-3/AM进行荧光染料负载,用激光共聚焦显微镜观察不同剂量CC l4作用不同时间[Ca2 ]i的变化。结果CC l4在5~15 mmol/L范围内可明显增加肝星状细胞[Ca2 ]i,且[Ca2 ]i随CC l4剂量的增大而升高(P<0.05),作用2 h后,各组[Ca2 ]i均上升,与对照组比较差异有显著性(P<0.05),4 h后各组[Ca2 ]i继续升高;8 h后各组[Ca2 ]i维持在较高水平,各组分别与作用4 h比较差异均无显著性(P<0.05)。结论CC l4可能引起肝星状细胞[Ca2 ]i升高。     

大麻素CB2受体激动剂AM1241对肝星状细胞影响

目的 探讨大麻素Ⅱ型受体(CB2)激动剂AM1241对大鼠肝星状细胞系(HSC-T6)影响及其机制。方法 将HSC-T6细胞随机分为对照组、氧化应激组及20、80μmol/L AM1241干预组;对照组正常培养,氧化应激组用含100 mU/L葡萄糖氧化酶(GO)完全培养液培养2 h;AM1241干预组分别加入20、80μmol/L的AM1241干预3 h后,再加入100 mU/L GO干预2 h;细胞免疫化学染色法检测HSC-T6细胞中α-平滑肌肌动蛋白(α-SMA)表达;酶联免疫法检测HSC-T6细胞培养液上清中I型胶原(Col I);硫代巴比妥酸法检测丙二醛含量;氮蓝四唑法检测超氧化物歧化酶(SOD)活力;Western blot检测HSC-T6细胞核转录相关因子(Nrf2)总蛋白与核蛋白含量。结果 与对照组比较,氧化应激组HSC-T6细胞胞浆中α-SMA、Col I表达量均增多(P<0.05);与氧化应激组比较,AM1241干预组HSC-T6细胞胞浆中α-SMA、Col I表达量均减少(P<0.05);与对照组比较,氧化应激组HSC-T6细胞中丙二醛含量上升,SOD活性下降(P<0.05);与氧化应激组比较,AM1241干预组HSC-T6细胞丙二醛含量下降,SOD活性上升(P<0.05);对照组、氧化应激组及20、80μmol/L AM1241干预组HSC-T6细胞中Nrf2总蛋白表达量分别为(0.62±0.021)、(0.60±0.015)、(0.59±0.020)、(0.61±0.032),各组差异无统计学意义(P>0.05);与氧化应激组比较,AM1241干预组Nrf2核蛋白表达量均增加(P<0.05)。结论 大麻素CB2受体激动剂AM1241可抑制氧化应激作用下HSC-T6细胞活化,其机制可能与AM1241促进HSC-T6细胞中Nrf2发生核内转移,增加抗氧化作用有关。     

Histone h3 modifications in rat hepatic stellate cells by ethanol

AIMS: Hepatic stellate cells (HSCs) play critical roles in the development of hepatic fibrosis caused by various agents including alcohol. Ethanol causes post-translational modification in histone. The goal of this study is to investigate whether ethanol affected acetylation and methylation of histone H3 in rat HSCs. METHODS: We isolated and separated HSCs using collagenase perfusion of liver followed by Nycodenz density gradient centrifugation. HSCs were divided and treated with different concentrations of ethanol for various times. Histone was isolated using acid extraction method. Acetylation and methylation of histone H3 at Lys9 was analysed by both western blot and fluorescein isothiocyanate (FITC) immunochemical stain. Acetylation of histone H3 at Lys9 (Ac-H3-lys9), Lys14 (Ac-H3-Lys14), Lys18 (Ac-H3-lys18), or Lys23 (Ac-H3-lys23) was checked by western blotting. RESULTS: At lysine 9, ethanol caused dose-dependent increase of Ac-H3 up to 200 mM. Ac-H3-lys9 increased with a maximum of 86-fold at 72 h and 200 mM ethanol treatment, and decreased thereafter. This increase was confirmed by both western blotting and FITC stain. At high dose, ethanol increased acetylation of histone H3 at Lys23 (Ac-H3-lys23), but it had no effect on Ac-H3-lys14 or Ac-H3-lys18. The intensity of the FITC-labelled dimethyl-histone H3 at Lys9 (Me-H3-lys9) antibody appeared to decrease slightly with increasing dose of ethanol. But this did not appear to change when monitored by western blotting. CONCLUSIONS: Ethanol caused dose and time-dependent increase in acetylation of histone H3 at Lys9, but not at Lys14 or Lys18. Compared with hepatocytes the Ac-H3-lys9 in HSCs required longer ethanol exposure. Levels of Me-H3-lys9 seemed to remain unaltered. Thus increase in Ac-H3-lys9 represents a nuclear-chromatin modification event in HSCs exposed to ethanol.     

亚砷酸钠对大鼠肝星状细胞增殖与凋亡的影响

目的探讨亚砷酸钠对大鼠肝星状细胞(HSC-T6)增殖与凋亡的影响。方法取处于对数生长期的HSC-T6细胞,调整细胞密度为4×10~4/ml,分别暴露于含终浓度为0(对照)、5、15、25μmol/L亚砷酸钠的DMEM高糖培养基24、48、72 h。采用MTT比色法检测细胞增殖活性;采用流式细胞术检测细胞早期凋亡率。结果随染毒剂量和时间增加,5μmol/L组的细胞增殖活性高于对照组,差异有统计学意义(P0.05),25μmol/L组的细胞增殖活性低于对照组,差异有统计学意义(P0.05)。HSC-T6细胞形态由染毒前的椭圆形和不规则形转变为染毒后的索条形,有纤维化倾向。随着染毒时间延长,染毒剂量升高,HSC-T6细胞早期凋亡率随之增高,差异有统计学意义(P0.05),具有剂量-效应和时间-效应关系。结论低剂量亚砷酸钠暴露促进肝星状细胞增殖,高剂量亚砷酸钠暴露抑制肝星状细胞增殖,会改变细胞形态,促进细胞凋亡,具有明显的细胞毒性。     

Antiproliferative effects of citrus limonoids against human neuroblastoma and colonic adenocarcinoma cells

Limonoids, a family of triterpenoids with putative anticancer properties, occur in fruits as glucosides and aglycones. Both highly purified forms were isolated from seeds and molasses of citrus fruits and tested for toxic effects against two human cancer cell lines, SH-SY5Y neuroblastoma and Caco-2 colonic adenocarcinoma, and a noncancerous mammalian epithelial Chinese hamster ovary (CHO) cells. Viability, as quantified by 3-[4,5-dimethylthiazol- 2-yl]-2,5-diphenyltetrazolium reduction and light microscopy, was shortened significantly (P < 0.001) in cancer cells exposed to aglycones, viz., limonin, nomilin, obacunone, and deacetylnomilin. SH-SY5Y cells were more sensitive than Caco-2 cells to the limonoids, whereas noncancerous CHO cells showed hardly any change in cell numbers or cell morphology. Aglycone toxicity was dose dependent, but below the killing potential of glucosides. This observation correlated with a slower rate of induction of caspase 3/7 activity by aglycones. A flow cytometric analysis of SH-SY5Y cells treated with glucosides and aglycones showed an increased ploidy, which is consistent with enhancing chromosomal abnormalities. The results confirm that limonoids exert a strong multifaceted lethal action against cancer cells, but are relatively ineffective against CHO cells. Of the two, metabolites derived from glucosides are the more likely progenitors of an apoptosis response in situ.     

Malondialdehyde-acetaldehyde-protein adducts increase secretion of chemokines by rat hepatic stellate cells.

Findings obtained from our recent studies have demonstrated that malondialdehyde, a product of lipid peroxidation, and acetaldehyde can react together with proteins in a synergistic manner and form hybrid protein conjugates, which have been designated as malondialdehyde-acetaldehyde (MAA)-protein adducts. These adducts have been detected in livers of ethanol-fed rats and are immunogenic because significant increases in circulating antibody titers against MAA-adducted proteins have been observed in ethanol-fed rats and more recently in human alcoholics. Although immunological factors may tend to perpetuate liver injury, little is known about the direct functional consequences of MAA-adducted proteins on the different cellular populations of the liver. Hepatic stellate cells (HSCs) have been shown to be pivotal in the pathogenesis of fibrosis and in the amplification and self-perpetuation of the inflammatory process. The present study was conducted to determine the effects of MAA-adducted proteins on the function of HSCs. Rat HSCs were exposed to various amounts of MAA-protein adducts and their unmodified controls, and the secretion of two chemokines, monocyte chemoattractant protein (MCP)-1 and macrophage inflammatory protein (MIP)-2, that are involved in the chemotaxis of monocytes/macrophages and neutrophils, respectively, was determined. We observed that bovine serum albumin-MAA induced a dose- and time-dependent increase in the secretion of both of these chemokines. These findings indicate that MAA-adducted proteins may play a role in the modulation of the hepatic inflammatory response and could contribute to the pathogenesis of alcoholic liver disease.     

神经生长因子诱导肝星状细胞凋亡及其相关机制的研究

目的观察神经生长因子（nerve growthfactor,NGF）对大鼠肝星状细胞（hepatic stellatecell,HSC）凋亡的影响,并探讨其可能的作用机制。方法体外培养大鼠肝星状细胞株HSC—T6,将HSC—T6与100ng／mlNGF孵育24h后,流式细胞术检测细胞凋亡;细胞免疫化学法检测HSC中凋亡相关基因P^53、Bcl-2、Caspase-3蛋白表达的情况;免疫荧光法检测NGF、神经生长因子低亲和力受体p75NTR表达的情况。结果NGF作用HSC后凋亡率较对照组明显增高[（22．364±9．51）％VS（5．88±1．36）％,P〈0．05]。凋亡相关蛋白P^53、Caspase-3的阳性细胞百分率与对照组比较明显增高[（78．41±4．00）％、（39．26±1．57）％VS（34．96±3．84）％、（9．27±1．01）％,P〈0．05],而Bcl-2表达实验组阳性细胞百分率较对照组降低[（18．12±1．38）％vs（91．53±2．98）％,P〈0．05]。NGF作用HSC后NGF表达增多（6．53±1．40vs1．77±0．17,P〈0．05）,而p75NTR表达无明显变化（3．52±0．36VS4．24±0．38,P〉0．05）。结论NGF可能通过使凋亡相关基因p、Caspase-3表达上调、Bcl-2表达下调,而诱导HSC凋亡。NGF作用HSC后可作为始动因子和效应因子增加NGF的表达,而对p75NTR表达无影响。     

Lycopene isomerisation and storage in an in vitro model of murine hepatic stellate cells

Background  Lycopene is a carotenoid whose biological activities and protective effect on prostate and breast cancer have been described, but little is known on its extra-intestinal metabolism and storage. While most alimentary lycopene is in all-trans configuration, in animal and human tissues approximately half of the lycopene is in cis isoforms. Aim of study  Our object was to monitor the capacity of storage, isomerisation, and intracellular localization of all-trans and cis lycopene in hepatic stellate cells, which are the major sites of metabolism and storage of retinoids and carotenoids in the body. Methods  We used the GRX cell line representative of murine hepatic stellate cells, incubated with 1–30 μM lycopene in culture medium. Analysis was done by high-performance liquid chromatography. Results  Lycopene was able to induce expression of the lipocyte phenotype and it was internalized into GRX cells. Its cellular release only occurred in presence of albumin with a rapid initial decrease of intracellular lycopene. A corresponding increase in the culture medium was observed at 24 h. All-trans, 13-cis and 9-cis lycopene isoforms were identified in all the cell compartments. The membrane fraction contained the major part of lycopene, followed by the cytoplasmic fraction, lipid droplets and nuclei. The ratio between all-trans and cis isomers was approximately 2/1 in the majority parts of cell compartments. Conclusions  This study identified a novel hepatic cell type able to store and isomerise lycopene. Liver can contribute to the serum and tissue equilibrium of cis/trans isomers of lycopene, and to participate in storage of lycopene under high extracellular concentration such as observed after the alimentary input.     

Ginsenoside Rb1 inhibits cell activation and liver fibrosis in rat hepatic stellate cells

Chronic hepatitis/cirrhosis is the eighth leading cause of death in Taiwan. Excess accumulated extracellular matrix produced by activated hepatic stellate cells (HSCs) is the major cause of liver fibrosis. Ginsenoside Rb1, the most active compound purified from ginseng, has been considered to be hepatoprotective. This study investigated the effects of ginsenoside Rb1 (98.8% purity) on activation, proliferation, and profibrotic factors in rat HSC-T6 cells under H?O? oxidative stress. Rat HSC-T6 cells were activated by 10 nM H?O? and then incubated with different concentrations of ginsenoside Rb1 (5, 10, 20, 40, and 80 μg/mL) for 24 hours. Medium containing 0.08% dimethyl sulfoxide or 5 mM N-acetyl-l-cysteine was used as a negative or positive control, respectively. The results showed that ginsenoside Rb1 at 5-40 μg/mL significantly reduced α-smooth muscle actin levels and at 5-80 μg/mL inhibited cell proliferation in HSC-T6 cells after induction with H?O? (P<.05). Collagen secreted by HSC-T6 cells was decreased by ginsenoside Rb1 at 5-80 μg/mL (P<.05). Protein expression of transforming growth factor-β1 (TGF-β1), matrix metalloproteinase (MMP)-2, and tissue inhibitor of metalloproteinase (TIMP)-1 was suppressed by ginsenoside Rb1 at 10-80 μg/mL (P<.05). In addition, mRNA expression of type I and III collagen, TGF-β1, and TIMP-1 was inhibited by ginsenoside Rb1 (10 and 80 μg/mL) (P<.05). Therefore, ginsenoside Rb1 exerted an antifibrotic effect on HSCs by inhibiting activation, proliferation, and expression of collagen, TGF-β1, MMP-2, and TIMP-1.     

HBx蛋白促进纤维化相关因子在人肝星状细胞中的表达

目的研究转染HBx基因的肝细胞在体外促进纤维化相关因子在肝星状细胞中的表达,进而探讨HBx促肝纤维化的机制。方法首先以表达HBx蛋白的肝细胞（QSG7701-HBx）与Lx-2细胞（人肝星状细胞株）共培养,并以转染pcDNA3空载体的肝细胞（QSG7701-pcDNA3）和母细胞QSG7701为对照;共培养后应用RT-PCR检测LX-2细胞α-SMA、TGF．[31、CTGF和Col Ⅰ（I型胶原）的mRNA表达;应用Western blot检测共培养后LX-2细胞α-SMA、TGF．131和CTGF蛋白表达;同时应用酶联免疫吸附法（ELISA）检测共培养后细胞上清液中ColⅠ浓度。结果（1）RT-PCR结果显示,与QSG7701-HBx细胞共培养的LX-2细胞的α-SMA、TGF-β1、CTGF和Col Ⅰ的mRNA表达明显高于两对照组QSG7701-pcDNA3和QSG7701（P〈0．05）。（2）Westem blot分析显示,与QSG7701-HBx细胞共培养的LX-2细胞的α-SMA、TGF—p1和CTGF蛋白表达也明显高于两对照组（P〈0．05）。（3）ELISA检测Lx·2细胞分别与QSG7701、QSG7701-pcDNA3和QSG7701-HBx细胞共培养的上清液colⅠ其浓度分别为（191．2±20．8）ns／ml、（200．2±21．6）ng／ml和（500．5±43．4）ng／ml,QSG7701-HBx明显高于两对照组（P〈0．05）,这表明HBx蛋白能促进LX．2细胞分泌colⅠ有助于肝纤维化的形成。结论与QSG7701-HBx细胞共培养后,肝星状细胞中的纤维化相关蛋白表达明显增强,体外实验证实HBx具有诱导肝纤维化的作用。     

ERK信号转导通路调控乙醛刺激的肝星状细胞增殖的研究

目的特异性ERK阻断剂PD98059作用于乙醛刺激的HSC后,观察HSC内ERK活性、细胞增殖、细胞周期时相和细胞周期蛋白(Cyclins)表达的变化;为肝纤维化的发生和防治提供依据.方法体外培养人鼠HSC;HSC经PD98059预处理,用乙醛刺激后收集细胞,分别采用Western?blot、MTT比色法、流式细胞仪、RT-PCR法检测ERK活性、细胞增殖、细胞周期时相及CycinnDlmRNA表达的变化.结果HSC被乙醛刺激后,磷酸化ERK(p-ERK)水平增高、细胞周期蛋白CyclinDlmRNA表达增加、细胞由G1-S期转化增多、促进细胞增殖;20、50、100rLmol几PD98059均能抑制乙醛刺激的HSC内p-ERK水平,50、100pmol几的PD98059可明显抑制乙醛刺激的HSC内CyclinDlmRNA表达,并明显抑制细胞由Gl-S期的转化和细胞增殖,与对照组比较有统计学差异(P<0.05).结论乙醛刺激HSC后,引起ERK信号传导通路活化;ERK信号传导通路调控乙醛刺激的HSC增殖可能与其调控HSC内CycinnDlmRNA表达和细胞周期变化有关.     

不同浓度甘草甜素对肝星状细胞增殖的影响及其调控机制的研究

目的探讨不同浓度甘草甜素对肝星状细胞增殖的影响及其调控机制的研究。方法用MTY法检测三组不同浓度甘草甜素对肝星状细胞增殖的抑制率,用免疫细胞化学法检测细胞周期素cyclinE的表达情况。结果MTT法检测不同药物浓度组：空白对照组、0．8mg／L甘草甜素组、1．2mg／L甘草甜素组、1．6mg／L甘草甜素组细胞增殖抑制率分别为0,2．73％,14．75％,25．96％,差异有统计学意义（P〈0．05）;不同浓度甘草甜素组中cyclinE阳性表达细胞数与对照组比较明显减少,且呈浓度依赖性,差异有统计学意义（P〈0．01）。结论甘草甜素能够浓度依赖性的抑制大鼠肝星状细胞增殖;甘草甜素可通过降低细胞周期素cyclinE的表达从而抑制大鼠肝星状细胞增殖。’     

The effects of hyperlipemia and obesity on tissue tocopherol levels in the rat

Zucker obese rats which exhibit both hyperlipemia and obesity and normal litter mates injected with Triton WR-1339 to induce hyperlipemia alone were used as models. Plasma total lipid (TL) and plasma tocopherol (αT) values increased significantly in both models. Neither model exhibited an increase in tissue αT levels known to accompany the increase in plasma αT levels in normal-lipemic animals. Previous literature had suggested that adiposity was the primary cause of the failure of tissues to accumulate αT. The hyperlipemic model demonstrated that the tissue αT levels were not elevated even in the absence of excess adiposity. Thus hyperlipemia alone produced the observed effects on tissue αT level. No relationship of tissue αT to degree of hyperlipemia or to levels of plasma αT was observed. Instead it was found that the parameter that defines the relationship of plasma levels of αT and TL to tissue levels of αT was the αT to TL ratio in plasma. Over a ratio range of 0.77 to 9.07 (normal, obese, and hyperlipemia animals) the tissue levels of αT of both testes and lungs gave a correlation coefficient of 0.84.