Kangxian ruangan keli inhibits hepatic stellate cell proliferation mediated by PDGF

AIM: To investigate the effect of Kangxian ruangan keli (KXR)on hepatic stellate cell (HSC) proliferation mediated by platelet-derived growth factor (PDGF) and the underlying mechanism.METHODS: In a serum-free culture system, HSCs were treated with a KXR preparation for 24 hours, followed by stimulation with PDGF-BB for 24 hours. Then the cells were incubated again in the medium containing KXR for 3 hours stimulated with PDGF-BB for 5 minutes, and collected. The proliferation of HSC was examined using an MTT assay and flow cytometry. Tyrosine phosphorylation was detected with Western blotting and visualized by the enhenced chemiluminescent (ECL) method.RESULTS: The OD values for the HSCs growing in the media without and with addition of PDGF were 0.17±0.06 and 0.82±0.05, respectively. The PDGF-induced increase was hindered remarkably by KXR preparation in a dosedependent manner. The reaction values for the systems with 5 mg/mL, 2.5 rng/mL and 1.25 mg/mL of KXR were 0.28±0.03,0.37±0.02 and 0.43±0.04, respectively. Mloreover, the percentages of S-phase cells in these KXR-containing culture systems were 10.95±1.35, 32.76±1.07 and 43.19±1.09,respectively, all of which were significantly lower than that in the culture free of KXR (68.24±2.72). In addition, the values for tyrosine-phosphorylated protein in HSCs treated with 5 mg/mL and 1.25 mg/mL of KXR were 0.1349±0.0072and 0.1658±0.0025, respectively, which were smaller than that in the cells treated only with PDGF-BB (0.1813±0.0117).CONCLUSION: Within the dose range used in the present study, KXR preparation shows an inhibitory effect on HSC proliferation induced by PDGF. The mechanism of this process may involve interference with tyrosine phosphorylation mediated by PDGF.     

抗纤软肝颗粒对血小板源生长因子诱导的肝星状细胞增殖的影响

目的:研究抗纤软肝颗粒(KXR)对血小板源生长因子(PDGF)诱导的肝星状细胞(HSC)增殖的影响.方法:采用无血清培养,不同浓度的KXR温育HSC 24 h后,PDGF-BB(10 ng/ml)刺激24 h,再加入上述浓度的KXR 3 h后,又加入PDGF-BB(10 ng/ml)作用5 min,然后收集细胞.采用细胞计数法及流式细胞仪测定细胞增殖及细胞周期.结果:无血清培养显示该方对于PDGF诱导的细胞增殖具有抑制作用,并呈剂量依赖性(P<0.01).流式细胞术分析提示KXR能抑制PDGF诱导的HSC DNA合成期及合成后期和分裂期DNA百分含量,阻断细胞由静止期/DNA合成前期向DNA合成期转化,呈剂量依赖性(5 mg/ml组作用最显著,P<0.01).结论:KXR能抑制PDGF诱导的HSC增殖.     

NAD(P)H oxidase plays a crucial role in PDGF-induced proliferation of hepatic stellate cells

The proliferation of hepatic stellate cells (HSCs) is a critical step in hepatic fibrogenesis. Platelet-derived growth factor (PDGF) is the most potent mitogen for HSCs. We investigated the role of nonphagocytic NAD(P)H oxidase-derived reactive oxygen species (ROS) in PDGF-induced HSC proliferation. The human HSC line, LI-90 cells, murine primary-cultured HSCs, and PDGF-BB were used in this study. We examined the mechanism of PDGF-BB-induced HSC proliferation in relation to the role of a ROS scavenger and diphenylene iodonium, an inhibitor of NAD(P)H oxidase. We also measured ROS production with the aid of chemiluminescence. We showed that PDGF-BB induced proliferation of HSCs through the intracellular production of ROS. We also demonstrated that HSCs expressed key components of nonphagocytic NAD(P)H oxidase (p22phox, gp91phox, p47phox, and p67phox) at both the messenger RNA and protein levels. Diphenylene iodonium suppressed PDGF-BB-induced ROS production and HSC proliferation. Coincubation of H2O2 and PDGF-BB restored the proliferation of HSCs that was inhibited by diphenylene iodonium pretreatment. Phosphorylation of the mitogen-activated protein kinase (MAPK) family constitutes a signal transduction pathway of cell proliferation. Our data demonstrate that NAD(P)H oxidase-derived ROS induce HSC proliferation mainly through the phosphorylation of p38 MAPK. Moreover, an in vivo hepatic fibrosis model also supported the critical role of NAD(P)H oxidase in the activation and proliferation of HSCs. In conclusion, NAD(P)H oxidase is expressed in HSCs and produces ROS via activation of NAD(P)H oxidase in response to PDGF-BB. ROS further induce HSC proliferation through the phosphorylation of p38 MAPK.     

莪术提取物对PDGF诱导的肝星状细胞内Ca2+和PI3-K的影响

目的:探讨莪术提取物药物血清对PDGF诱导的肝星状细胞(HSC)内Ca2 、PI3-K的影响。方法:制备药物血清,不同浓度的莪术提取物药物血清温育肝星状细胞24小时后,PDGF-BB(10ng/ml)刺激24小时,再加入上述浓度的莪术提取物药物血清,3小时后,又加入PDGF-BB(10ng/ml)作用5分钟,然后收集细胞。采用钙指示剂Fura-2/Am测定细胞内Ca2 ,免疫印迹化学发光法检测PI3-K的表达。结果:不同浓度的莪术提取物药物血清与同浓度的生理盐水药物血清比较,能显著抑制PDGF诱导的胞内Ca2 浓度升高(P<0.01)。经10%莪术提取物药物血清处理的HSC,其PDGF诱导的PI3-K表达水平较10%生理盐水药物血清组显著降低(P<0.01)。结论:莪术提取物药物血清能抑制PDGF诱导的肝星状细胞内Ca2 内流及PI3-K的表达。     

Intracellular pathways mediating Na+/H+ exchange activation by platelet-derived growth factor in rat hepatic stellate cells

BACKGROUND & AIMS: The Na+/H+ exchanger is the main intracellular pH regulator in hepatic stellate cells (HSCs), and its activity is increased by platelet-derived growth factor (PDGF). Amiloride, an Na+/H+ exchange inhibitor, reduces PDGF-induced HSC proliferation, suggesting that the Na+/H+ exchanger plays a role in regulating HSC proliferative response. The aim of this study was to characterize the intracellular pathways mediating activation of the Na+/H+ exchanger by PDGF in HSCs. METHODS: The activity of the Na+/H+ exchanger and HSC proliferation rate were evaluated under control condition and after incubation with PDGF in the absence or presence of specific inhibitors of the main intracellular pathways of signal transduction. Na+/H+ exchange protein expression was evaluated by means of Western blot. RESULTS: PDGF induced a significant increase in the activity of the Na+/H+ exchanger without modifying protein expression. Inhibition of the calcium/calmodulin- and protein kinase C-dependent pathways resulted in a significant inhibition of both Na+/H+ exchange activity and of PDGF-induced HSC proliferation. The involvement of the two pathways was confirmed by showing that incubation of HSCs with both phorbol-12-myristate-13-acetate, a potent protein kinase C activator, and thapsigargin, which increases intracellular calcium levels, significantly increased both the Na+/H+ exchanger activity and HSC proliferation rate. Inhibition of the protein kinase A pathway did not modify either PDGF-induced Na+/H+ exchange activation or PDGF-induced HSC proliferation. On the contrary, inhibition of the mitogen-activated protein kinase- and of phosphatidylinositol 3-kinase-dependent pathways significantly reduced PDGF-induced HSC proliferation without affecting the activity of the Na+/H+ exchanger. CONCLUSIONS: Activation of the Na+/H+ exchanger by PDGF in HSCs is mediated by calcium/calmodulin- and protein kinase C-dependent pathways. PDGF-induced HSC proliferation is mediated by Na+/H+ exchange-dependent and -independent pathways.     

Inhibition of hepatic stellate cell proliferation and activation by the semisynthetic analogue of fumagillin TNP-470 in rats

Proliferation and activation of hepatic stellate cells (HSCs) are critical steps for the development of postnecrotic fibrosis in the liver. The present study aimed to reveal the inhibitory effect of the semisynthetic analogue of fumagillin TNP-470 on these events for its possible use as an antifibrogenic agent. Rat models of carbon tetrachloride (CCl(4))- and dimethylnitrosamine-induced hepatic fibrosis were used for an in vivo study. In both models, the fibrotic area was considerably decreased by concurrent repetitive subcutaneous injections of 30 mg/kg body weight of TNP-470. In CCl(4)-induced fibrosis, factor VIII-related antigen-positive blood vessels, desmin-, or alpha-smooth muscle actin (alphaSMA)-positive mesenchymal cells, bromodeoxyuridine (BrdU)-positive mesenchymal cells also decreased in number by treatment with TNP-470. In in vitro experiments, a supplement of 1,000 ng/mL TNP-470 suppressed BrdU incorporation and cyclins D1, D2, and E expression by cultured HSCs in the absence and/or presence of platelet-derived growth factor (PDGF). Expression of HSC activation markers, i.e., alphaSMA and PDGF receptor beta, was also suppressed. The present results indicate that TNP-470 inhibits HSC proliferation by blocking the cell-cycle transition from G1 to S and HSC activation, and, as the consequence, prevents the progression of hepatic fibrosis, probably being coupled with its antiangiogenic effect.     

四甲基吡嗪对大鼠肝星状细胞肌细胞增强因子2A及α-平滑肌肌动蛋白表达的影响

[目的]观察肌细胞增强因子2A (Myocyte enhancer factor 2A、MEF2A)在肝星状细胞(Hepatic Stellate Cell、HSC)活化过程中的可能作用及四甲基吡嗪对其影响,进一步探讨四甲基吡嗪抗肝纤维化的作用机制.[方法]采用SD大鼠肝脏原位灌流消化法获得HSC,并原代及传代培养,分离的HSC在塑料细胞培养皿中培养后逐步活化,分别收集新分离(0 d)和经培养(1、2、3、4、5、6、7、8 d)的HSC,观察MEF2A与HSC活化指标α-平滑肌肌动蛋白(α-smooth muscle action、α-SMA)表达的关系;取传2～4代HSC,加四甲基吡嗪至终浓度50、100、150、200mg/L,分组培养48 h,观察四甲基吡嗪对HSC增殖抑制作用的同时,对MEF2A基因及蛋白表达的影响.[结果]①随着HSC培养逐步活化,细胞内MEF2A及α-SMA逐步增加,二者呈正相关(r=0.90,P＜0.05),且MEF2ADNA结合活性同步增强.②随着四甲基吡嗪浓度增加,对HSC增殖的抑制作用增强,同时对MEF2A表达抑制作用逐渐增强.[结论]MEF2A可能参与了HSC活化过程,四甲基吡嗪抑制HSC增殖作用可能与有效抑制MEF2A表达有关.     

Progelatinase A is produced and activated by rat hepatic stellate cells and promotes their proliferation.

Activated hepatic stellate cells (HSCs) are a potential source of gelatinase A, which accumulates in fibrotic livers. Progelatinase A activation requires its binding to a complex of membrane-type matrix metalloproteinase (MT-MMP) and tissue inhibitor of metalloproteinases (TIMP)-2. These studies examine gelatinase A, MT1-MMP, and TIMP-2 synthesis by HSCs during activation in vitro and the potential role of gelatinase A in promoting HSC proliferation. Gelatinase A, MT1-MMP, and TIMP-2 messenger RNA (mRNA) were all upregulated in HSCs activated on plastic over 5 to 14 days. Gelatinase A expression was maximal at 7 days of culture, coinciding with the peak of HSC proliferation and the onset of procollagen I and alpha-smooth muscle actin (alpha-SMA) mRNA expression. Active forms of gelatinase A of 62 kd and 66 kd were secreted by activated HSCs and reached a maximum of 12.1% of total enzyme in 14-day culture supernatants. Treatment of HSCs with concanavalin A (con A) induced activation of MT1-MMP and enhanced secretion of activated gelatinase A, which reached a maximum of 44.4% of the total enzyme secreted into culture supernatants using 30 microgram/mL con A. [(14)C]-gelatin degradation assays confirmed the presence of gelatinolytic activity in activated HSC supernatants, which reached a maximum level at 7 days of culture. Antisense oligonucleotide inhibition of endogenous progelatinase A production, or the MMP inhibitor 1,10-phenanthroline inhibited (3)H-thymidine incorporation into HSC DNA by greater than 50%. We conclude that HSCs produce progelatinase A during activation in vitro and activate this enzyme coincident with MT1-MMP and TIMP-2 synthesis. Gelatinase A activity is required for maximal proliferation of HSCs in vitro suggesting this metalloproteinase is an autocrine proliferation factor for HSCs.     

Effect of caffeic acid phenethyl ester on proliferation and apoptosis of hepatic stellate cells in vitro

AIM: To investigate the role of nuclear factor-κB (NF-κB)inhibitor caffeic acid phenethy1 ester (CAPE) in the proliferation, collagen synthesis and apoptosis of hepatic stellate cells (HSCs) of rats. METHODS: The HSCs from rats were isolated and cultured in Dulbecco's Modified Eagle's Medium (DMEM) and treated with CAPE. The proliferation and collagen synthesis of HSCs were determined by 3H-TdR and 3H-proline incorporation respectively, and the expression of type Ⅰ, Ⅲ procollagen genes was further explored byin situ hybridization. Apoptosis cell indices (AIs) were examined using terminal deoxynucleotidyl transferase- mediated DIG-dUTP nick end labeling (TUNEL). RESULTS: Tn activated HSC in culture, CAPE significantly inhibited 3H-TdR and 3H-proline incorporation by HSCs at concentrations of 5 μmol/L and 10 μmol/L respectively. CAPE also reduced the type I procollagen gene expression (P＜0.05)at higher concentration. Apoptosis of HSC was induced by CAPE and the AIs were time-and dose-dependently increased from 2.82+0.73 % to 7.66±1.25 % at 12 h (P＜0.01) and from 3.15±0.88 % to 10.6L±2.88 % at 24 h (P＜0.01). CONCLUSION: CAPE inhibits proliferation and collagen synthesis of HSC at lower concentration and induces HSC apoptosis at higher concentration.     

Critical role of tumor necrosis factor receptor 1, but not 2, in hepatic stellate cell proliferation, extracellular matrix remodeling, and liver fibrogenesis

Tumor necrosis factor (TNF) has been implicated in the progression of many chronic liver diseases leading to fibrosis; however, the role of TNF in fibrogenesis is controversial and the specific contribution of TNF receptors to hepatic stellate cell (HSC) activation remains to be established. Using HSCs from wild-type, TNF-receptor-1 (TNFR1) knockout, TNF-receptor-2 (TNFR2) knockout, or TNFR1/R2 double-knockout (TNFR-DKO) mice, we show that loss of both TNF receptors reduced procollagen-α1(I) expression, slowed down HSC proliferation, and impaired platelet-derived growth factor (PDGF)-induced promitogenic signaling in HSCs. TNFR-DKO HSCs exhibited decreased AKT phosphorylation and in vitro proliferation in response to PDGF. These effects were reproduced in TNFR1 knockout, but not TNFR2 knockout, HSCs. In addition, matrix metalloproteinase 9 (MMP-9) expression was dependent on TNF binding to TNFR1 in primary mouse HSCs. These results were validated in the human HSC cell line, LX2, using neutralizing antibodies against TNFR1 and TNFR2. Moreover, in vivo liver damage and fibrogenesis after bile-duct ligation were reduced in TNFR-DKO and TNFR1 knockout mice, compared to wild-type or TNFR2 knockout mice. CONCLUSION: TNF regulates HSC biology through its binding to TNFR1, which is required for HSC proliferation and MMP-9 expression. These data indicate a regulatory role for TNF in extracellular matrix remodeling and liver fibrosis, suggesting that targeting TNFR1 may be of benefit to attenuate liver fibrogenesis.     

大麻素受体2介导的N-花生四烯酸氨基乙醇对肝星状细胞增殖和活化的影响

目的 观察内源性大麻素N-花生四烯酸氨基乙醇(AEA)及大麻素受体(CBR)2对肝星状细胞(HSC)增殖活化的影响,以探讨内源性大麻素及其受体系统在肝纤维化发展中的作用.方法 采用免疫荧光观察血小板衍生生长因子(PDGF)刺激前后HSC中CBR1和CBR2的表达.Western blot、PCR法观察不同浓度AEA及CBR2拮抗剂AM630对PDGF刺激下HSC增殖及活化的影响,同时用四甲基偶氮唑盐、流式细胞仪分析AEA对HSC活力及凋亡的影响.结果 HSC中CBR2的表达较CBR1高(F=116.797,P<0.01),且PDGF刺激后CBR2的表达明显增强(F=7.878,P<0.05).AEA可剂量依赖地抑制HSC的增殖,在浓度为10,20、50μmol/L时抑制率分别为7.12%±0.34%、12.52%±0.78%、80.13%±1.57%,差异有统计学意义(F=533.41,P<0.01);但对HSC凋亡的影响不明显.同时AEA可抑制HSC的活化指标α-平滑肌肌动蛋白、转化生长因子β1、Ⅰ型胶原、Ⅲ型胶原及基质金属蛋白酶抑制因子等的表达,但这种抑制作用在给予CBR2拮抗剂AM630后明显减弱,差异有统计学意义(P<0.05).结论 CBR2在AEA引起的HSC增殖及活化抑制中起关键作用,AEA和CBR2可望成为肝纤维治疗的新靶点.     

抗纤软肝颗粒对大鼠肝星状细胞增殖的影响

目的:探讨抗纤软肝颗粒(KXRG)对大鼠肝星状细胞(HSC)增殖的影响。方法:传代培养的HSC-T6(肝星状细胞系)与KXRG(1.25mg/ml、2.5mg/ml、5mg/ml)及其药物血清(5%、10%、20%)共同培养72小时后,应用MTT法测定细胞增殖、流式细胞仪测定HSC细胞周期各时相的DNA含量。结果:KXRG及药物血清均能显著抑制HSC的增殖,使细胞周期阻滞于S期,且2.5mg/ml药物和10%药物血清作用最强(P0.01)。结论:KXRG通过抑制HSC的活化,阻滞其细胞周期的正常进行,进而抑制HSC增殖,从而起到抗肝纤维化的作用。     

黄芩甙抗肝星状细胞增殖及胶原合成的作用

目的研究黄芩甙对大鼠肝星状细胞活化、增殖及细胞外基质合成的作用,探讨黄芩甙抗肝纤维化的机制。方法采用胶原酶循环灌流法和密度梯度离心法分离肝星状细胞。不同浓度黄芩甙作用后,通过观察细胞贴壁及细胞形态变化情况来检测细胞活化：采用MTT法检测细胞增殖;免疫细胞化学法检测Ⅰ、Ⅲ型胶原及层粘连蛋白的合成。结果黄芩甙（75～1200μg/mL）可抑制HSC活化,MTT法示75μg／mL、150μg／mL、300μmL、600μg／mL、1200μg／mL黄芩甙作用于HSC的A值分别为（0．060±6．53）×10^-2、（0．052±7．38）×10^9、（0．036±1．26）×10^-3、（0．023±1．72）×10^-3、（0．013±4．01）×10^-3,空白对照组A值为（0．065±1．32）×10^4,F值=1147．611,P〈0．05。黄芩甙可抑制活化的HSC增殖,减少HSCⅠ、Ⅲ型胶原及层粘连蛋白合成。结论黄芩甙抗肝纤维化作用主要机制可能为黄芩甙抑制肝星状细胞活化、增殖,抑制细胞胶原蛋白及糖蛋“等细胞外基质合成.     

干扰素α对Ⅰ型胶原及转化生长因子β1基因表达的影响

目的 观察干扰素α(IFN α)对血小板衍生生长因子-BB(PDGF-BB)刺激的大鼠肝星状细胞(HSC)分泌Ⅰ型胶原及转化生长因子β1(TGF β1)基因表达的影响,探讨IFN α抗肝纤维化的可能机制.方法 体外培养大鼠HSC系rHSC-99,分别用0、0.0125、0.0250、0.0500,0.1000、0.2000,0.4000 ng/ml IFN α,PDGF-BB干预和两者共同干预,用四甲基偶氮唑盐实验观察各组对HSC细胞活力的影响,采用逆转录聚合酶链反应方法测定各组对HSC细胞Ⅰ型胶原mRNA和TGF β1 mRNA表达的影响.结果 (1)HSC细胞活力(A值)PDGF-BB干预组为1.35±0.22,空白对照组为0.89±0.12,两组比较,F=16.311,P＜0.05,差异有统计学意义,说明PDGF-BB可提高HSC细胞活力.0.025,0.050、0.100、0.2000,0.400ng/ml IFN α加PDGF-BB共干预组,A值分别为0.84±0.18.0.45±0.15、0.26±0.01、0.33±0.07,0.30±0.06,较空白对照组明显降低,F=7.430,P＜0.05,差异有统计学意义,说明IFN α与PDGF-BB共同作用可抑制HSC细胞活力,且在0.025-0.100 ng/ml范围内随着IFN α浓度的增加其抑制作用越明显.(2)0.050、0.100、0.200ng/ml IFN α加PDGF-BB共干预各组Ⅰ型胶原mRNA相对表达值分别为0.94±0.19、0.61±0.12,0.52±0.02,空白对照组为1.41±0.01,共干预各组比空白对照组均明显降低,F=127.921,P＜0.05,差异有统计学意义.0.050、0.100,0.200ng/mlIFN α加PDGF-BB共干预组各组TGFβ1 mRNA相对表达值分别为1.18±0.06、1.15±0.10、1.39±0.04,空白对照组为1.62±0.12,共干预各组比空白对照组均明显降低,F=82.115,P＜0.05,差异有统计学意义,说明IFN α与PDGF-BB共同作用对HSC细胞Ⅰ型胶原、TGFβ1基因的表达有抑制作用,且随着浓度的增加其抑制作用越明显.结论 IFN α对PDGF-BB诱导的HSC细胞活力及Ⅰ型胶原、TGF β1基因的表达有抑制作用,且随着浓度的增加其抑制作用越明显.这可能是IFN α发挥抗肝纤维化作用的途径之一.     

黄芪注射液对大鼠肝星状细胞作用的研究

目的探讨黄芪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.黄芪注射液(0mg/ml、25mg/ml、50 mg/ml、100 mg/ml、200 ml、400 mg/ml)作用不同时间(24 h、48 h、72h)后,采用MTF法OD值检测细胞活化增殖情况.黄芪注射液(200 mg/ml)作用24h和48 h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黄芪注射液对活化的肝星状细胞凋亡的影响.结果黄芪注射液各浓度组(除25 mg/ml作用24 h组外)OD值较对照组明显降低(P＜0.05);黄芪注射液200 mg/ml组作用24和48 h流式细胞术检测出G2-M期的细胞数均明显高于正常对照组(P＜0.01);黄芪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.结论黄芪注射液主要是通过抑制肝星状细胞增殖的G2-M期而产生抗肝纤维化作用的.     

Effect of rat serum containing Biejiajian oral liquid on proliferation of rat hepatic stellate cells

AIM: Liver fibrosis is a common pathological process of chronic liver diseases. Activation of hepatic stellate cells (HSCs) is the key issue in the occurrence of liver fibrosis. In this study, we observed the inhibitory action of rat serum containing Biejiajian oral liquid (BOL), a decoction of turtle shell, on proliferation of rat HSCs, and to explore the anti-hepatofibrotic mechanisms of BOL. METHODS: A rat model of hepatic fibrosis was induced by subcutaneous injection of CCl(4). Serum containing low, medium and high dosages of BOL was prepared respectively. Normal and fibrotic HSCs were isolated and cultured. The effect of sera containing BOL on proliferation of HSCs was determined by (3)H-TdR incorporation. RESULTS: The inhibitory rate of normal rat HSC proliferation caused by 100 mL/mL sera containing medium and high dosages of BOL showed a remarkable difference as compared with that caused by colchicine (medium dosage group: 34.56+/-4.21% vs 29.12+/-2.85%, P<0.01; high dosage group: 37.82+/-1.32% vs 29.12+/-2.85%, P<0.01). The inhibitory rate of fibrotic rat HSC proliferation caused by 100 mL/L serum containing medium and high dosages of BOL showed a remarkable difference as compared with that caused by colchicine (medium dosage group: 51.31+/-3.14% vs 38.32+/-2.65%, P<0.01; high dosage group: 60.15+/-5.36% vs 38.32+/-2.65%, P<0.01). The inhibitory rate of normal rat HSC proliferation caused by 100 mL/L and 200 mL/L sera containing a medium dosage of BOL showed a significant difference as compared with that caused by 50 mL/L (100 mL/L group: 69.02+/-9.96% vs 50.82+/-9.28%, P<0.05; 200 mL/L group: 81.78+/-8.92% vs 50.82+/-9.28%, P<0.01). The inhibitory rate of fibrotic rat HSC proliferation caused by 100 mL/L and 200 mL/L sera containing a medium dosage of BOL showed a significant difference as compared with that caused by 50 mL/L (100 mL/L group: 72.19+/-10.96% vs 61.38+/-7.16%, P<0.05; 200 mL/L group: 87.16+/-8.54% vs 61.38+/-7.16%, P<0.01). CONCLUSION: Rat serum containing BOL can inhibit proliferation of rat HSCs, and the inhibition depends on the dosage and concentration of BOL. The inhibitory effect on HSC proliferation is one of the main anti-hepatofibrotic mechanisms of BOL.     

TAK1/JNK and p38 have opposite effects on rat hepatic stellate cells.

After liver injury, hepatic stellate cells (HSCs) undergo a process of activation with expression of smooth muscle alpha-actin (alpha-SMA), an increased proliferation rate, and a dramatic increase in synthesis of type I collagen. The intracellular signaling mechanisms of activation and perpetuation of the activated phenotype in HSCs are largely unknown. In this study the role of the stress-activated protein kinases, c-Jun N-terminal kinase (JNK) and p38, were evaluated in primary cultures of rat HSCs. The effect of JNK was assessed by using an adenovirus expressing a dominant negative form of transforming growth factor beta (TGF-beta)-activated kinase 1 (TAK1) (Ad5dnTAK1) and a new selective pharmacologic inhibitor SP600125. The effect of p38 was assessed with the selective pharmacologic inhibitor SB203580. These kinases were inhibited starting either in quiescent HSCs (culture day 1) or in activated HSCs (culture day 5). Although blocking TAK1/JNK and p38 decreased the expression of alpha-SMA protein in early stages of HSC activation, no effect was observed when TAK1/JNK or p38 were inhibited in activated HSCs. JNK inhibition increased and p38 inhibition decreased collagen alpha1(I) mRNA level as measured by RNase protection assays, with maximal effects observed in early stages of HSC activation. Furthermore, TAK1/JNK inhibition decreased HSC proliferation, whereas p38 inhibition led to an increased proliferation rate of HSCs, independently of its activation status. These results show novel roles for the TAK1/JNK pathway and p38 during HSC activation in culture. Despite similar activators of TAK1/JNK and p38, their functions in HSCs are distinct and opposed.