Reverse transformation of hepatic myofibroblast-like cells by TGFbeta1/LAP

Working with Immortalized Hepatic Stellate Cell Lines

Hepatic stellate cells (HSCs) are the major cellular source of extracellular matrix production in the liver. Therefore, this cell population has received considerable attention in studies investigating fundamental features of hepatic fibrosis. However, the limited supply and ever-increasing demand for these cells, combined with the additional tightening of formal standards in animal welfare policy, make working with these primary cells increasingly difficult. Moreover, researchers working in biomedical research are challenged to implement the 3R principle of "replacement," "reduction," and "refinement" in their work. This principle, originally proposed in 1959 by William M. S. Russell and Rex L. Burch, is now widely endorsed by legislators and regulatory bodies in many countries as a roadmap to tackle the ethical dilemma associated with animal experimentation. As such, working with immortalized HSC lines is a good alternative to limit the number of animals and their suffering in biomedical research. This article summarizes issues that need to be considered when working with established HSC cell lines and provides general guidelines for the maintenance and storage of HSC lines from mouse, rat, and humans.

Genetic Characterization of Rat Hepatic Stellate Cell Line HSC-T6 for In Vitro Cell Line Authentication

Immortalized hepatic stellate cells (HSCs) established from mouse, rat, and humans are valuable in vitro models for the biomedical investigation of liver biology. These cell lines are homogenous, thereby providing consistent and reproducible results. They grow more robustly than primary HSCs and provide an unlimited supply of proteins or nucleic acids for biochemical studies. Moreover, they can overcome ethical concerns associated with the use of animal and human tissue and allow for fostering of the 3R principle of replacement, reduction, and refinement proposed in 1959 by William M. S. Russell and Rex L. Burch. Nevertheless, working with continuous cell lines also has some disadvantages. In particular, there are ample examples in which genetic drift and cell misidentification has led to invalid data. Therefore, many journals and granting agencies now recommend proper cell line authentication. We herein describe the genetic characterization of the rat HSC line HSC-T6, which was introduced as a new in vitro model for the study of retinoid metabolism. The consensus chromosome markers, outlined primarily through multicolor spectral karyotyping (SKY), demonstrate that apart from the large derivative chromosome 1 (RNO1), at least two additional chromosomes (RNO4 and RNO7) are found to be in three copies in all metaphases. Additionally, we have defined a short tandem repeat (STR) profile for HSC-T6, including 31 species-specific markers. The typical features of these cells have been further determined by electron microscopy, Western blotting, and Rhodamine-Phalloidin staining. Finally, we have analyzed the transcriptome of HSC-T6 cells by mRNA sequencing (mRNA-Seq) using next generation sequencing (NGS).

Adipose-derived stem cells alleviate liver injury induced by type 1 diabetes mellitus by inhibiting mitochondrial stress and attenuating inflammation

Background

Type 1 diabetes mellitus (T1D) is a worldwide health priority due to autoimmune destruction and is associated with an increased risk of multiorgan complications. Among these complications, effective interventions for liver injury, which can progress to liver fibrosis and hepatocellular carcinoma, are lacking. Although stem cell injection has a therapeutic effect on T1D, whether it can cure liver injury and the underlying mechanisms need further investigation.

Methods

Sprague–Dawley rats with streptozotocin (STZ)-induced T1D were treated with adipose-derived stem cell (ADSC) or PBS via the tail vein formed the ADSC group or STZ group. Body weights and blood glucose levels were examined weekly for 6 weeks. RNA-seq and PCR array were used to detect the difference in gene expression of the livers between groups.

Results

In this study, we found that ADSCs injection alleviated hepatic oxidative stress and injury and improved liver function in rats with T1D; potential mechanisms included cytokine activity, energy metabolism and immune regulation were potentially involved, as determined by RNA-seq. Moreover, ADSC treatment altered the fibroblast growth factor 21 (FGF21) and transforming growth factor β (TGF-β) levels in T1D rat livers, implying its repair capacity. Disordered intracellular energy metabolism, which is closely related to mitochondrial stress and dysfunction, was inhibited by ADSC treatment. PCR array and ingenuity pathway analyses suggested that the ADSC-induced suppression of mitochondrial stress is related to decreased necroptosis and apoptosis. Moreover, mitochondria-related alterations caused liver inflammation, resulting in liver injury involving the T lymphocyte-mediated immune response.

Conclusions

Overall, these results improve our understanding of the curative effect of ADSCs on T1D complications: ADSCs attenuate liver injury by inhibiting mitochondrial stress (apoptosis and dysfunctional energy metabolism) and alleviating inflammation (inflammasome expression and immune disorder). These results are important for early intervention in liver injury and for delaying the development of liver lesions in patients with T1D.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02760-z.

A Long-term Treatment with Silybin in Patients with Non-alcoholic Steatohepatitis Stimulates Catalase Activity in Human Endothelial Cells

AIM

To compare levels of oxidative stress markers in patients' sera with non-alcoholic steatohepatitis (NASH) treated for 12 months (T₁₂) with silybin conjugated with phosphatidylcholine (Realsil®) (R) or placebo (P) and investigate oxidative stress responses in human endothelial cells conditioned with patients' sera.

PATIENTS AND METHODS

We recruited twenty-seven patients with histological NASH. We measured thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD) and catalase (CAT) activities in human endothelial cells conditioned with patients' sera exposed or not to H₂O₂ Results: We found in decreased-TBARS patients' sera, at T₁₂, a decrease of alanine aminotransferase (p=0.038), transforming growth factor-beta (p=0.009) and procollagen I (p=0.001). By dividing patients into two groups, increased (P-I/R-I) and decreased TBARS (P-II/R-II) at T₁₂ compared to T₀, we found an increased CAT activity in conditioned endothelial cells at T12 in both groups (p=0.05 and p=0.001, respectively).

CONCLUSION

Realsil® may be effective against endothelial dysfunction by stimulating the cellular antioxidant defense.

Experimental models of liver fibrosis

Hepatic fibrosis is a wound healing response to insults and as such affects the entire world population. In industrialized countries, the main causes of liver fibrosis include alcohol abuse, chronic hepatitis virus infection and non-alcoholic steatohepatitis. A central event in liver fibrosis is the activation of hepatic stellate cells, which is triggered by a plethora of signaling pathways. Liver fibrosis can progress into more severe stages, known as cirrhosis, when liver acini are substituted by nodules, and further to hepatocellular carcinoma. Considerable efforts are currently devoted to liver fibrosis research, not only with the goal of further elucidating the molecular mechanisms that drive this disease, but equally in view of establishing effective diagnostic and therapeutic strategies. The present paper provides a state-of-the-art overview of in vivo and in vitro models used in the field of experimental liver fibrosis research.

18α-glycyrrhizin ameliorates oxidative stress in rats with CCl4-induced liver fibrosis

AIM: To investigate the effect of 18α-glycyrrhizin (18α-GL) on oxidative stress in rats with experimental liver fibrosis.

METHODS: Male SD rats were randomly divided into five groups: control group, fibrosis group, low-, medium-, and high-dose GL groups. Except the control group, liver fibrosis was induced by subcutaneous injection of 40% CCl₄ for 8 weeks in rats of the other groups. The three GL groups were treated with different doses of GL (6.25, 12.5, 25 mg/kg, respectively). All the rats were sacrificed at the end of the 8th week. Histopathological changes in the liver tissue were evaluated by HE staining and Masson collagen staining. The contents of MDA and HNE and the activity of SOD and GSH-PX in liver tissue homogenate were determined.

RESULTS: 18α-GL could inhibit CCl₄-induced liver fibrosis. The contents of MDA and HNE were elevated in the liver fibrosis group (both P < 0.05), but 18α-GL could markedly increase SOD and GSH-PX activity (both P < 0.05) and reduce the levels of MDA and HNE to protect the liver from damage.

CONCLUSION: 18α-GL can ameliorate hepatic histopathological changes and reduce hepatic lipid peroxidation, thus exerting antioxidant and antifibrotic effects in rats with experimental liver fibrosis.

Inhibitory effects of microRNA 19b in hepatic stellate cell-mediated fibrogenesis

Hepatic stellate cell (HSC) activation is a pivotal event in initiation and progression of hepatic fibrosis and a major contributor to collagen deposition driven by transforming growth factor beta (TGF-β). MicroRNAs (miRs), small noncoding RNAs modulating messenger RNA (mRNA) and protein expression, have emerged as key regulatory molecules in chronic liver disease. We investigated differentially expressed miRs in quiescent and activated HSCs to identify novel regulators of profibrotic TGF-β signaling. miR microarray analysis was performed on quiescent and activated rat HSCs. Members of the miR-17-92 cluster (19a, 19b, 92a) were significantly down-regulated in activated HSCs. Because miR 19b showed the highest fold-change of the cluster members, activated HSCs were transfected with miR 19b mimic or negative control and TGF-β signaling and HSC activation assessed. miR 19b expression was determined in fibrotic rat and human liver specimens. miR 19b mimic negatively regulated TGF-β signaling components demonstrated by decreased TGF-β receptor II (TGF-βRII) and SMAD3 expression. Computational prediction of miR 19b binding to the 3' untranslated region of TGF-βRII was validated by luciferase reporter assay. Inhibition of TGF-β signaling by miR 19b was confirmed by decreased expression of type I collagen and by blocking TGF-β-induced expression of α1(I) and α2(I) procollagen mRNAs. miR 19b blunted the activated HSC phenotype by morphological assessment and decreased smooth muscle α-actin expression. Additionally, miR 19b expression was markedly diminished in fibrotic rat liver compared with normal liver; similarly, miR 19b expression was markedly down-regulated in fibrotic compared with normal human livers.

CONCLUSION

miR 19b is a novel regulator of TGF-β signaling in HSCs, suggesting a potential therapeutic approach for hepatic fibrosis.

Advances in understanding the role of transforming growth factor-β1 in the pathogenesis of liver fibrosis

Transforming growth factor-β1 (TGF-β1) is one of the most important cytokines leading to liver fibrosis and is most closely to the development and progression of liver fibrosis and extracellular matrix (ECM) metabolism. Numerous studies have demonstrated that TGF-β1 plays a significant role in the occurrence, development and progression of live fibrosis. Many therapeutic approaches targeting TGF-β1, especially gene therapy and immunotherapy, have been proposed to treat hepatic fibrosis in recent years. Here, we will review the recent advances in understanding the role of TGF-β1 in the pathogenesis of liver fibrosis.

Establishment and characterization of hepatic stem-like cell lines from normal adult rat liver

The liver is a unique organ with the potential to regenerate from injury. Hepatic stem cells contribute to liver regeneration when surviving hepatocytes in injured liver are unable to proliferate. To investigate the mechanism of liver regeneration in vitro, we established hepatic stem cell lines named HY1, HY2 and HY3, derived from a healthy liver of adult rat. HY cells showed an expression pattern similar to oval cells, and efficiently induced hepatic differentiation following sequential treatment with type I collagen, transforming growth factor-beta1 (TGF-beta1), and hepatocyte growth factor (HGF) or oncostatin M (OSM). These results suggested that HY cells are liver stem cells representing an excellent tool for in vitro studies on liver regeneration.

Oxidative stress and hepatic injury

Oxidative stress, initiated by reactive oxygen species, is the collective pathophysiological mechanism of many hepatopathies. Oxidative stress results in hepatic injury mainly by priming lipid peroxidation to change the function of biological membrane, covalent immobilization of biomacromolecules and destroying the enzyme activity considering cytokine (TNF-α and NF-κB) interaction. The role of oxidative stress in many hepatopathies such as fatty liver desease, viral hepatitis, hepatic fibrosis is innegligible.

Effect of Jiazhu on α-SMA and TGF-β1 expression in rats with hepatic fibrosis

AIM: To investigate the effect of Jiazhu on α-SMA and TGF-β1 expression in the liver of rats with hepatic fibrosis and its anti-fibrosis mechanism.

METHODS: A model of rat hepatic fibrosis was induced by injecting 40% CCl4, which was interfered with high [2.0 g/(kg·d)], medium [1.0 g/(kg·d)] and low doses [0.5 g/(kg·d)] of Jiazhu. Hepatic function and serum TGF-β1 were examined. Expression of α-SMA and TGF-β1 was detected by immunohistochemistry and RT-PCR.

RESULTS: Compared with the model group, the levels of aspartate transaminase and alanine transaminase were significantly decreased in the high, medium and low Jiazhu dose groups. Total protein and albumin increased while serum bilirub and TGF-β1 were significantly reduced. The expression of α-SMA and TGF-β1 in liver tissue was decreased. The mRNA expression, stained area and gray scale of α-SMA and TGF-β1 in the high, medium and low Jiazhu dose groups were significantly different compared with the model group(α-SMA: 9.21 ± 1.12、12.63 ± 2.42、14.23 ± 1.57 vs 16.32 ± 2.14, P < 0.01、P < 0.01、P < 0.05; TGF-β1 mRNA: 5.58 ± 0.80、8.62 ± 1.16、11.92 ± 1.35 vs 14.57±1.59, P < 0.01、P < 0.01、P < 0.01), (dyeing area of α-SMA: 9.21% ± 1.29%、12.63% ± 1.44%、14.23% ± 1.41% vs 16.32% ± 1.75%, P < 0.01、P < 0.01、P < 0.05; dyeing area of TGF-β1: 5.31% ± 0.70%、8.37% ± 1.09%、11.92% ± 1.42% vs 14.47% ± 1.48%, P < 0.01、P < 0.01、P < 0.01), (gray scale of α-SMA: 91.29 ± 9.53、99.55 ± 11.83、107.18 ± 12.06 vs 116.44 ± 12.97, P < 0.01、P < 0.01、P < 0.05; gray scale of TGF-β1: 89.96 ± 9.64、106.92 ± 13.90、110.50 ± 12.91 vs 127.13 ± 14.88, P < 0.01、P < 0.01、P < 0.05).

CONCLUSION: Jiazhu can inhibit rat hepatic fibrosis induced by CCL₄.

Immortal hepatic stellate cell lines: useful tools to study hepatic stellate cell biology and function?

At the cellular level, the activation and transdifferentiation of quiescent hepatic stellate cells (HSC) into myofibroblasts is the key process involved in hepatic fibrogenesis that is associated with an increased and altered deposition of extracellular matrix components in the liver. The temporal sequence of molecular events associated with stellate cell activation turned out to be appropriately mimicked when HSC isolated from normal livers are cultured on uncoated plastic surface. Therefore, cultured primary cells isolated from rodents and human beings are common in vitro models in investigations addressing these issues of hepatic stellate biology and function. However, the limited supply, cost-effective isolation procedure and the ever growing need have resulted in efforts to establish immortalized stellate cell lines having the advantage of virtually unlimited access. They allow rapid screening for disease-associated factors and restrict the necessary number of animal experiments. From the first description of an immortal HSC line in 1986, a huge number of studies were conducted with these established cell lines. However, differences in morphology, growth characteristics and anomalies of chromosome number and structure make the applications of these models questionable. Here, we summarize the history and cellular characteristics of respective cell lines and discuss the differences of continuous HSC lines and their primary counterparts.

In vivo transfection of C/EBP-alpha gene could ameliorate CCL(4)-induced hepatic fibrosis in mice

AIM

Hepatic stellate cells (HSCs) play a key role in liver fibrosis. CCAAT/enhancer-binding proteins-alpha (C/EBP-alpha) can inhibit HSCs activation in vitro, as described in our previous study. However, little is known about the in vivo effect of C/EBP-alpha gene in hepatic fibrosis.

METHODS

Male BALB/c mice were injected by hydrodynamic protocol with pIRES2-EGFP-C/EBPalpha expression vector from the first to the fourth week (early intervention) or from the ninth to the 12th week (late intervention) after CCl(4) injection, respectively. Successful transfection of vector and the expression of C/EBP-alpha were confirmed with the appearance of green fluorescence in liver cells, immunohistochemical staining and the western blot.

RESULTS

High expression of C/EBP-alpha gene in liver cells, especially in non-parenchymal cells, could reduce the content of collagens by 82.5% and 72.3% (Sirius red staining + image analysis) and the content of hydroxyproline by 56.3% and 51.6%, respectively, in the early and late intervention experiments.

CONCLUSION

It is evident that exogenous C/EBP-alpha gene has an early and late intervention role in mice liver fibrosis.

Effects of perindopril and valsartan on expression of transforming growth factor-beta-Smads in experimental hepatic fibrosis in rats

BACKGROUND

Previous studies have shown that the renin-angiotensin system (RAS) plays an important role in the pathogenesis of hepatic fibrosis, and blockers of the RAS may be active as an antifibrogenic goal. However, the potential role of RAS inhibition on expression transforming growth factor (TGF)-beta-Smads in hepatic fibrosis remains unknown. The aim of this study was to investigate the effect and mechanism of an angiotensin-converting enzyme inhibitor (perindopril) and an angiotensin II receptor blocker (valsartan) on TGF-beta1 and TGF receptor II (TRII) mRNA, Smad3 and Smad7 in fibrotic hepatic livers in rats.

METHODS

Sixty Wistar rats were randomly divided into four study groups (n = 15 for each group), including normal controls, hepatic fibrosis models, and two treated groups with either perindopril or valsartan, starting from the fourth week after being exposed to carbon tetrachloride (CCl(4)) for 4 weeks. The levels of TGF-beta and TRII mRNA in liver tissue were analyzed by RT-PCR. The expressions of TGF-beta1, Smad3 and Smad7 in liver tissues were evaluated by immunohistochemistry. The liver histopathology was examined by hematoxylin and eosin (HE) staining and by electron microscopy, respectively. The liver function and serum hyaluronic acid were also assayed by biochemistry and radioimmunoassay.

RESULTS

Compared with the hepatic fibrosis models, the levels of TGF-beta1, TRII mRNA and the expression Smad3 significantly decreased in the two treated groups, and the expression of Smad7 was significantly increased in the liver of rats treated with perindopril or valsartan (P < 0.05 or P < 0.01). The histological changes and ultrastructure of fibrotic liver, liver function and hyaluronic acid also remarkably improved in the treated rats.

CONCLUSIONS

The angiotensin-converting enzyme inhibitors perindopril and valsartan have a protective effect on liver injury and can ameliorate hepatic fibrosis in rats induced by CCl(4). The mechanisms may be associated with their effects of down-regulating TGF-beta1, TRII mRNA and smad3, and up-regulating Smad7.

Anti-TGF-beta strategies for the treatment of chronic liver disease

Permanent alcohol abuse may lead to chronic liver injury with deleterious sequelae such as liver cirrhosis and hepatocellular carcinoma. Mechanisms of fibrogenesis encompass recruitment of inflammatory cells at the site of injury and cytokine mediated activation of hepatic stellate cells (HSC) with accumulation of interstitial collagens. HSC transdifferentiation and accompanying apoptosis result in destruction of liver architecture and are therefore key steps of disease progression. TGF-beta represents the main profibrogenic cytokine in liver fibrosis and other fibroproliferative disorders by inducing extracellular matrix deposition as part of the wound healing response. In parallel, TGF-beta triggers hepatocytes that are strongly responsive for this cytokine, to undergo apoptosis, thereby providing space for HSC proliferation and generation of a collagenous matrix. Anti TGF-beta approaches were established and successfully utilized for the treatment of experimental fibrogenesis. Dominant negative TGF-beta receptors (TbetaR), generated by fusing the Fc domain of human IgG and the N-terminal (extracellular) fragment of TbetaRII (Fc:TbetaRII) were applied to suppress fibrosis. Similarly TGF-beta binding proteins like decorin, antagonistic cytokines such as bone morphogenetic protein-7, hepatocyte growth factor, IL-10, or IFN-gamma were as efficient as camostat mesilate, a protease inhibitor that possibly abrogated proteolytic activation of TGF-beta. Further, our group recently overexpressed Smad7 in bile duct ligation induced liver fibrosis and achieved efficient inhibition of intracellular TGF-beta signaling, thereby counteracting profibrogenic effects in cultured HSC and in vivo. A direct link between the effect of alcohol and TGF-beta exists through reactive oxygen species that are generated in liver cells by alcohol metabolism and represent activators of TGF-beta signaling. Thus, soluble TbetaRII expression reduced experimental fibrogenesis in vitro and in vivo partially by decreasing intracellular ROS and inhibiting NADH oxidase. Approaches that specifically target profibrogenic TGF-beta signaling are promising to treat alcoholic liver disease in the future. However, to ensure safety for the patients to be treated, approaches with strong specificity need to be established. Therefore, it is essential to delineate the profibrogenic actions of TGF-beta and the influence of alcohol abuse in molecular detail.

Tetrandrine inhibits activation of rat hepatic stellate cells stimulated by transforming growth factor-beta in vitro via up-regulation of Smad 7

Tetrandrine is a bisbenzylisoquinoline alkaloid derived from the root of a Chinese herbal medicine Stephania tetrandra S. Moore, which has been used traditionally for the treatment of hepatofibrogenic disease in China for several decades. In the present study, the inhibitory effects of tetrandrine lower concentrations (0.25, 0.5, 1, 2 mg/L) on culture-activation and transforming growth factor-beta(1) (TGF-beta(1))-stimulated activation of quiescent rat hepatic stellate cells (HSCs) in vitro were assessed, and the possible relations between the underlying mechanism of these effects and TGF-beta signaling via its receptors were investigated. As shown by the examination of alpha-SMA using immunocytochemical staining or Western blot, tetrandrine inhibited both culture-activation and TGF-beta(1)-stimulated activation of HSCs. Further investigations revealed that, in this process, TGF-beta(1) mRNA expression was suppressed significantly in contrast to an up-regulation of Smad 7, while the expressions of type I and type II TGF-beta(1) receptors and Smad 3 mRNA were insignificantly changed by tetrandrine. These results suggest that tetrandrine at lower concentrations has a significant inhibiting effect on culture-activation and TGF-beta(1)-stimulated activation of rat HSCs, and that it may be due to an up-regulation of Smad 7 which in turn blocks TGF-beta(1) expression and its downstream signaling.

Tetrandrine inhibits activation of rat hepatic stellate cells in vitro via transforming growth factor-β signaling

AIM: To investigate the effect of various concentrations of tetrandrine on activation of quiescent rat hepatic stellate cells (HSCs) and transforming growth factor-β (TGF-β) signaling in vitro.

METHODS: HSCs were isolated from rats by in situ perfusion of liver and 18% Nycodenz gradient centrifugation, and primarily cultured on uncoated plastic plates for 24 h with DMEM containing 20% fetal bovine serum (FBS/DMEM) before the culture medium was substituted with 2% FBS/DMEM for another 24 h. Then, the HSCs were cultured in 2% FBS/DMEM with tetrandrine (0.25, 0.5, 1, 2 mg/L, respectively). Cell morphological features were observed under an inverted microscope, smooth muscle-α-actin (α-SMA) was detected by immunocytochemistry and image analysis system, laminin (LN) and type III procollagen (PCIII) in supernatants were determined by radioimmunoassay. TGF-β₁ mRNA, Smad 7 mRNA and Smad 7 protein were analyzed with RT-PCR and Western blotting, respectively.

RESULTS: Tetrandrine at the concentrations of 0.25-2 mg/L prevented morphological transformation of HSC from the quiescent state to the activated one, while α-SMA, LN and PCIII expressions were inhibited. As estimated by gray values, the expression of α-SMA in tetrandrine groups (0.25, 0.5, 1, 2 mg/L) was reduced from 21.3% to 42.2% (control: 0.67, tetrandrine groups: 0.82, 0.85, 0.96, or 0.96, respectively, which were statistically different from the control, P<0.01), and the difference was more significant in tetrandrine at 1 and 2 mg/L. The content of LN in supernatants was significantly decreased in tetrandrine groups to 58.5%, 69.1%, 65.8% or 60.0% that of the control respectively, and that of PCIII to 84.6%, 81.5%, 75.7% or 80.7% respectively (P<0.05 vs control), with no significant difference among tetrandrine groups. RT-PCR showed that TGF-β₁ mRNA expression was reduced by tetrandrine treatments from 56.56% to 87.90% in comparison with the control, while Smad 7 mRNA was increased 1.4-4.8 times. The TGF-β₁ mRNA and Smad 7 mRNA expression was in a significant negative correlation (r = -0.755, P<0.01), and both were significantly correlated with α-SMA protein expression (r = -0.938, P<0.01; r = 0.938, P<0.01, respectively). The up-regulation of Smad 7 protein by tetrandrine (1 mg/L) was confirmed by Western blotting as well.

CONCLUSION: Tetrandrine has a direct inhibiting effect on the activation of rat HSCs in culture. It up-regulates the expression of Smad 7 which in turn blocks TGF-β₁ expression and signaling.

Involvement of C/EBP-alpha gene in in vitro activation of rat hepatic stellate cells

Hepatic stellate cells (HSCs) play key roles in hepatic fibrosis. One of the most striking alterations in activated HSCs is loss of cytoplasmic lipid droplets. However, the association of lipid storage with the activation of HSCs remains unclear. CCAAT/enhancer-binding proteins family (C/EBPs), especially C/EBP-alpha, controls differentiation of adipocytes. We suggested that C/EBP-alpha gene may be involved in HSCs activation. The present results showed that the expression levels of C/EBP-alpha and C/EBP-beta genes declined in activated HSCs. Over-expression of C/EBP-alpha gene in activated HSCs: (1) inhibited HSCs proliferation, extracellular matrix-producing, alpha-smooth muscle actin gene expression, and induced rebound of cytoplasmic lipid droplets; (2) reduced retinoic acid receptor-beta, C/EBP-delta and -beta gene expressions, but increased the active form C/EBP-beta PSer(105), and induced retinoid X receptor-alpha gene expression; and (3) did not affect the protein level of p16INK4a, p21Cip1/WAF1 or p27Kip1. In conclusions, C/EBP-alpha gene is involved in in vitro activation of rat HSCs.

Effect of Chinese drug compound Ganzhifu on liver fibrosis in rats

AIM: To investigate the effect of compound Ganzhifu on experimental hepatic fibrosis and its possible mechanism.

METHODS: Forty-five Wistar rats were randomly divided into four groups: normal (N) group, Ganzhifu (G) group, colchicine (C) group and model (M) group. All the rats, except those in N group, were given CCl₄ by subcutaneous injection and alcohol (10%) by oral administration to establish the model of hepatic fibrosis. At the same time, the rats in G, C or M group were treated through stomach irrigation with Ganzhifu, colchicine or saline, respectively. Blood was collected for the examination of liver function and serum fibrosis markers. Hydroxyproline (Hyp), malondial dehyde (MDA) content, and superoxide disumutase (SOD) activity were determined in liver tissues. HE, Masson and Gorden-Sweet staining were used to examine the pathological changes in liver tissue sections. Inflammation and fibrosis were evaluated by semi-quantitative scoring system (SSS). In addition, The expression of typeI, III, IV collagens was detected by immunohistochemistry.

RESULTS: Compared with that in M group, liver function was improved remarkably in G group, and there were significant decreases in the liver fibrosis markers (Hyp: 1.52±0.35 mg/g vs 1.12±0.29 mg/g, P<0.05; MDA: 16.3±6.0 mmol/g vs

8.8±2.1 mmol/g, P<0.01). However, the SOD activity was notably elevated (86.33±17.74 nkat/g vs 122.01±19.12 nkat/g, P<0.01). Less inflammation, lower degree of fibrosis and reduced content of typeI, III, IV collagens were observed in G group than in M group. No significant difference was found between the effects of Ganzhifu and colchicines against fibrosis.

CONCLUSION: Ganzhifu can protect liver from fibrosis and the mechanism may be related to its anti-oxidative effect.

Establishment and identification of a novel immortalized rat hepatic stellate cell line HSC-PQ

AIM: To establish and identify a novel immortalized rat hepatic stellate cell (HSC) line.

METHODS: Primary HSCs were isolated from the liver of adult male Sprague-Dawley rats by a combination of pronase-collagenase perfusion and density gradient centrifugation. Then a new HSC line, being HSC-PQ, was established, cultured, and passaged by way of cellular clone. Furthermore, cellular dynamics, light microscopy, transmission electron microscopy, and immunocytochemistry were employed to investigate characteristics of the HSC line.

RESULTS: About 2×10⁷ HSCs could be harvested from a Sprague-Dawley rat with the live rate over 95% and purity over 90%. Afterwards, HSC-PQ line was obtained on the basis of total activation of primary HSCs. The phenotype of HSC-PQ cells resembled that of fibroblasts. Firstly, the existence of a-SMA as well as desmin in these cells exhibited their HSC-derived-myofibroblast identity clearly. Secondly, both the doubling time of about 75 hours, and the stable expression of extracellular matrixs including collagen type I, collagen type III, fibronectin, laminin, etc. showed the fibroblast-like-characteristics of HSC-PQ line. But collagen IV could not be detected in cytoplasm. In addition, maintaining over one year, 32 passages of the cell line might demonstrate its immortalisation.

CONCLUSION: We have established a new immortalized rat HSC line (HSC-PQ), which shares most of the characteristics with primary activated rat HSCs.