Hepatic Stellate Cell Line HSC-T6 Research Articles

Hyaluronic acid modified extracellular vesicles targeting hepatic stellate cells to attenuate hepatic fibrosis

RationaleTransforming growth factor-beta1 (TGF-β1) plays a pivotal role in promoting hepatic fibrosis, pirfenidone (PFD) could inhibit TGF-β1 signaling pathway to alleviate hepatic stellate cells (HSC) activation mediated hepatic fibrosis. The targeting delivery strategy of PFD to hepatic stellate cells is a challenge. Extracellular vesicles (EVs), cell-derived membranous particles are intraluminal nano-vesicles that play a vital role in intercellular communication, they also be considered as an ideal nano-carrier. MethodsIn this study, we developed a target strategy to deliver PFD to HSC with CD44 over-expression by EVs, hyaluronic acid (HA) modified DSPE-PEG2000 endows the active targeting ability of activated HSCs to PFD-loaded EVs. ResultsIn both rat hepatic stellate cell line HSC-T6 and rat hepatocyte cell line BRL, HA@EVs-PFD demonstrated the capacity to down-regulate the expression of collagen-synthesis-related proteins and showed superior inhibition efficacy of HSC-T6 activation compared to free PFD. In hepatic fibrosis model, 4 weeks of HA@EVs-PFD treatment resulted in a reduction in liver collagen fibers, significant improvement in hepatic cell morphology, and amelioration of hepatic fibrosis. ConclusionsHA@EVs-PFD, as a drug delivery system that effectively targets and inhibits activated HSCs to treat hepatic fibrosis, holds promise as a potential therapeutic agent against hepatic fibrosis.

MiR-340 mediates the involvement of high mobility group box 1 in the pathogenesis of liver fibrosis

Objective: To explore the pathogenic mechanism of the miR-340/high mobility group box 1 (HMGB1) axis in the formation of liver fibrosis. Methods: A rat liver fibrosis model was established by injecting CCl(4) intraperitoneally. miRNAs targeting and validating HMGB1 were selected with gene microarrays after screening the differentially expressed miRNAs in rats with normal and hepatic fibrosis. The effect of miRNA expressional changes on HMGB1 levels was detected by qPCR. Dual luciferase gene reporter assays (LUC) was used to verify the targeting relationship between miR-340 and HMGB1. The proliferative activity of the hepatic stellate cell line HSC-T6 was detected by thiazolyl blue tetrazolium bromide (MTT) assay after co-transfection of miRNA mimics and HMGB1 overexpression vector, and the expression of extracellular matrix (ECM) proteins type I collagen and α-smooth muscle actin (SMA) was detected by western blot. Statistical analysis was performed by analysis of variance and the LSD-t test. Results: Hematoxylin-eosin and Masson staining results showed that the rat model of liver fibrosis was successfully established. Gene microarray analysis and bioinformatics prediction had detected eight miRNAs possibly targeting HMGB1, and animal model validation had detected miR-340. qPCR detection results showed that miR-340 had inhibited the expression of HMGB1, and a luciferase complementation assay suggested that miR-340 had targeted HMGB1. Functional experiments results showed that HMGB1 overexpression had enhanced cell proliferation activity and the expression of type I collagen and α-SMA, while miR-340 mimics had not only inhibited cell proliferation activity and the expression of HMGB1, type I collagen, and α-SMA, but also partially reversed the promoting effect of HMGB1 on cell proliferation and ECM synthesis. Conclusion: miR-340 targets HMGB1 to inhibit the proliferation and ECM deposition in hepatic stellate cells and plays a protective role during the process of liver fibrosis.

MiR-146b-5p activation of hepatic stellate cells contributes to the progression of fibrosis by directly targeting HIPK1.

The present study aimed to explore the biological functions of microRNA (miR)-146b-5p and homeodomain interacting protein kinase 1 (HIPK1) in the progression of hepatic fibrosis (HF) and to identify the underlying mechanism. A rat HF model was established by administering a subcutaneous injection of carbon tetrachloride (CCl4). Relative levels of miR-146b-5p and HIPK1 in fibrotic rat liver tissues and the rat hepatic stellate cell (HSC) line HSC-T6 were measured by quantitative reverse transcription PCR, western blotting and immunohistochemistry. Following activation of HSC-T6 cells by lipopolysaccharide (LPS) induction, cell viability was examined by MTT assay. Transfection of miR-146b-5p mimic or inhibitor into HSC-T6 cells was performed, with the aim to identify the influence of miR-146b-5p on HSC-T6 cell behavior. The targeting relationship between miR-146b-5p and HIPK1 was predicted by TargetScan 7.2 and StarBase 3.0 and it was later verified by a dual-luciferase reporter assay. Through lentivirus transfection, the biological function of HIPK1 in regulating the progression of HF and the underlying mechanism were investigated. The results showed that miR-146b-5p was upregulated in liver tissues of rats with HF and activated HSC-T6 cells, while HIPK1 was downregulated in liver tissues of rats with HF and activated HSC-T6 cells. miR-146b-5p was able to upregulate the activation markers of LPS-induced HSC-T6 cells, upregulate COL1A1 and TGF-β, increase cell viability and contribute to fibrosis progression. HIPK1 was validated as the direct target of miR-146b-5p and its overexpression could effectively reduce the effect of miR-146b-5p in contribution to the progression of HF. In conclusion, miR-146b-5p was significantly upregulated during the progression of HF. By targeting and downregulating HIPK1, miR-146b-5p could significantly activate HSCs, upregulate COL1A1 and TGF-β and contribute to fibrosis progression. miR-146b-5p is a potential biomarker and therapeutic target for HF.

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).

Effect of SEPT6 on the biological behavior of hepatic stellate cells and liver fibrosis in rats and its mechanism

Hepatic stellate cells (HSCs) are key effectors during the development of liver fibrosis. Septin 6 (SEPT6) is a highly evolutionarily conserved GTP-binding protein that regulates various cell biological behaviors. The expression and function of SEPT6 in HSCs remain unknown. Here we demonstrate that SEPT6 expression is significantly elevated following the activation of primary rat HSCs, the human hepatic stellate cell line LX-2 and the rat hepatic stellate cell line HSC-T6, as well as in both human and rat fibrotic liver tissue. In vitro, the overexpression of SEPT6 promoted HSCs activation, proliferation, cell cycle progression and migration and inhibited HSCs apoptosis. In contrast, knockdown of SEPT6 exerted the opposite effects on HSCs. Mechanistically, SEPT6 exerted its pro-fibrogenic effect by promoting the expression of TGF-β1 and the phosphorylation of Smad2, Smad3, extracellular-signal-regulated kinase, c-Jun NH2-terminal kinase, stress-activated protein kinase-2, and protein kinase B. However, in HSC-T6 cells, blockade of the TGF-β1/Smad signaling pathway by SB431542 significantly decreased the expression of α-smooth muscle actin, cyclin D1, BCL2, and matrix metalloproteinase-2 and -9, which had been enhanced by SEPT6 overexpression. In vivo, adenovirus-mediated SEPT6 inhibition attenuated thioacetamide (TAA)-induced liver fibrosis in rats by decreasing the deposition of the extracellular matrix (ECM). SEPT6 inhibition decreased the proliferation capacity of HSCs and induced apoptosis of HSCs. Collectively, our results reveal that SEPT6 regulates various biological behaviors in HSCs through TGF-β1/Smad, mitogen-activated protein kinases and phosphatidylinositol-3-kinase/protein kinase B signaling pathways, thus promoting liver fibrosis.The cytoskeletal GTPase SEPT6 is elevated during hepatic stellate cell (HSC) activation and in liver fibrosis. SEPT6 promotes HSC activation, proliferation, cell cycle progression, survival and migration through the TGF-β1/Smad, MAPK and PI3K/AKT signaling pathways. Adenovirus-mediated SEPT6 inhibition attenuates thioacetamide-induced liver fibrosis.

ASIC1a promotes high glucose and PDGF-induced hepatic stellate cell activation by inducing autophagy through CaMKKβ/ERK signaling pathway

It is well known that the diabetes mellitus complicates liver fibrosis with high morbidity, and Acid-sensing ion Channel 1a (ASIC1a) plays an important role in the development of diabetes and liver fibrosis. However, the underlying mechanism about how diabetes influences the progression of liver fibrosis remains unclear. This study was to investigate the relationship between autophagy and ASIC1a in the process of liver fibrosis under hyperglycemia. Interestingly, our study showed that the autophagy was elevated in the livers from diabetes combined with liver fibrosis double model in vivo and also in rat hepatic stellate cell line HSC-T6 after stimulation with high glucose and platelet-derived growth factor (PDGF) in vitro, and this response could be attenuated by treatment with ASIC1a nonspecific inhibitor Amiloride or specific ShRNA for ASIC1a. Furthermore, inhibition of autophagy treated with 3-MA significantly attenuated HSC-T6 activation and proliferation. Mechanistically, CaMKKβ/ERK pathway was activated in HSC-T6 after stimulation with high glucose and PDGF, and could be suppressed by Amiloride. Collectively, we concluded that autophagy induced by ASIC1a contributes to HSC-T6 activation, which ing pathway.

Carapax Trionycis extracts inhibit fibrogenesis of activated hepatic stellate cells via TGF-β1/Smad and NFκB signaling

Carapax Trionycis is used as a traditional Chinese medicine with a long history of clinical application in China, and it represents an essential medication used for liver fibrosis treatment. Previous studies demonstrated that Carapax Trionycis extracts protect liver against fibrosis in CCL4-induced animal models. This study investigated the anti-fibrotic molecular mechanisms exerted by Carapax Trionycis extracts with molecular weight less than 6 KD (CT6) in rat hepatic stellate cell line HSC-T6 activated by TGF-β1. HSC-T6 cells induced by TGF-β1 were used to evaluate CT6 anti-fibrotic effect in vitro. CCK8 was used to evaluate cell viability and CT6 effect on HSC-T6 proliferation. ELISA was performed to detect the presence of inflammatory cytokines. Western blot and q-PCR were performed to explore the molecular mechanisms. Our data demonstrated that CT6 did not clearly affect cell viability but suppressed TGF-β1-induced HSC-T6 proliferation. Collagen I and α-smooth muscle actin (α-SMA) protein levels were decreased by CT6 in TGF-β1-induced HSC-T6, followed by the inhibition of TIMP1, TIMP2 and TGF-β1/Smad pathway. Furthermore, CT6 decreased Jun D and p-p65 protein levels, down-regulated Tgf-β1, Tnf-α, Il-1β, Il-6 mRNA and TNF-α, IL-1β and IL-6 expression in TGF-β1-treated HSC-T6. These results suggested that CT6 inhibited HSC-T6 activation induced by TGF-β1, indicating the potential therapeutic effect of these extracts against liver fibrosis.

Saikosaponin a Induces Apoptosis through Mitochondria-Dependent Pathway in Hepatic Stellate Cells.

Saikosaponin a (SSa) is one of the main active components of Bupleurum falcatum. It is commonly used to treat liver injury and fibrosis in traditional Chinese medicine. Our previous study showed that SSa induces apoptosis and inhibits the proliferation of rat hepatic stellate cell (HSC) line HSC-T6. The aim of the present study was to elucidate the mechanism of SSa-mediated apoptosis. Rat HSC cell line HSC-T6 and human HSC cell line LX-2 were used in this study. SSa triggered cell death mainly by apoptosis, as indicated by the typical morphological changes, sub-G1 phase of cell cycle increase, and activation of the caspase-9/caspase-3 cascade. In addition, SSa-induced apoptosis was partially inhibited by the caspase-3 inhibitor Z-DEVD-FMK, suggesting an involvement of caspase-3 dependent and independent pathways. Moreover, SSa upregulated pro-apoptotic proteins [BAK, Bcl-2-associated death promoter (BAD), and p53 upregulated modulator of apoptosis (PUMA)] and downregulated anti-apoptotic proteins (Bcl-2). In the mitochondria, SSa triggered the translocation of BAX and BAK from the cytosol to the outer membrane, resulting in a reduction of mitochondrial functions and membrane potential and subsequent release of apoptotic factors. Therefore, this study demonstrates that SSa induces apoptosis through the intrinsic mitochondrial-dependent pathway in HSCs.

Protective effects of curcumin against liver fibrosis through modulating DNA methylation

Recent research has demonstrated that advanced liver fibrosis in patients could be reversed, but no approved agents are available for the treatment and prevention of liver fibrosis in humans. Curcumin (CUR) is the principal curcuminoid of turmeric. Inhibitory effects of CUR and its underlying mechanisms in liver fibrogenesis have been explored. In the present study, we hypothesized that epigenetic mechanisms contribute to the protective effects of CUR against liver fibrosis. We used CCl4-induced liver injury in BALB/c mice and the rat hepatic stellate cell line HSC-T6 as experimental models. Genomic DNA methylation was analyzed by MeDIP-chip and verified by real-time PCR on MeDIP-enriched DNA. The mRNA and protein expressions of DNMT1, α-SMA, and Col1α1 were determined by real-time PCR and Western blotting, respectively. The methylation statuses of FGFR3, FZD10, Gpx4, and Hoxd3 were further confirmed by quantitative methylation-specific PCR (qMSP). Our results showed that CUR treatment reversed liver injury in vivo and in vitro, possibly through down regulation of DNMT1, α-SMA, and Col1α1 and by demethylation of the key genes. In conclusion, aberrant methylation is closely associated with liver fibrosis and CUR treatment may reverse liver fibrosis by epigenetic mechanisms.

ATGL and CGI-58 are lipid droplet proteins of the hepatic stellate cell line HSC-T6

Lipid droplets (LDs) of hepatic stellate cells (HSCs) contain large amounts of vitamin A [in the form of retinyl esters (REs)] as well as other neutral lipids such as TGs. During times of insufficient vitamin A availability, RE stores are mobilized to ensure a constant supply to the body. To date, little is known about the enzymes responsible for the hydrolysis of neutral lipid esters, in particular of REs, in HSCs. In this study, we aimed to identify LD-associated neutral lipid hydrolases by a proteomic approach using the rat stellate cell line HSC-T6. First, we loaded cells with retinol and FAs to promote lipid synthesis and deposition within LDs. Then, LDs were isolated and lipid composition and the LD proteome were analyzed. Among other proteins, we found perilipin 2, adipose TG lipase (ATGL), and comparative gene identification-58 (CGI-58), known and established LD proteins. Bioinformatic search of the LD proteome for α/β-hydrolase fold-containing proteins revealed no yet uncharacterized neutral lipid hydrolases. In in vitro activity assays, we show that rat (r)ATGL, coactivated by rat (r)CGI-58, efficiently hydrolyzes TGs and REs. These findings suggest that rATGL and rCGI-58 are LD-resident proteins in HSCs and participate in the mobilization of both REs and TGs.

Cytoglobin expression in the hepatic stellate cell line HSC-T6 is regulated by extracellular matrix proteins dependent on FAK-signalling.

BackgroundFibrosis is a physiological response to cellular injury in the liver and is mediated by the activation of hepatic stellate cells resulting in the replacement of hepatocytes with extracellular matrix comprised principally of collagen 1 to form a hepatic scar. Although the novel hexaco-ordinated globin cytoglobin was identified in activated hepatic stellate cells more than 10 years ago, its role in stellate cell biology and liver fibrosis remains enigmatic.ResultsIn the current study, we investigated the role of different extracellular matrix proteins in stellate cell proliferation, activation (alpha smooth muscle actin expression and retinoic acid uptake) and cytoglobin expression. Our results demonstrate that cytoglobin expression is correlated with a more quiescent phenotype of stellate cells in culture and that cytoglobin is regulated by the extracellular matrix through integrin signalling dependent on activation of focal adhesion kinase.ConclusionsAlthough further studies are required, we provide evidence that cytoglobin is a negative regulator of stellate cell activation and therefore may represent a novel target for anti-fibrotic treatments in the future.Electronic supplementary materialThe online version of this article (doi:10.1186/s13069-015-0032-y) contains supplementary material, which is available to authorized users.

Identification of 6-octadecynoic acid from a methanol extract of Marrubium vulgare L. as a peroxisome proliferator-activated receptor γ agonist

6-Octadecynoic acid (6-ODA), a fatty acid with a triple bond, was identified in the methanol extract of Marrubium vulgare L. as an agonist of peroxisome proliferator-activated receptor γ (PPARγ). Fibrogenesis caused by hepatic stellate cells is inhibited by PPARγ whose ligands are clinically used for the treatment of diabetes. Plant extracts of Marrubium vulgare L., were screened for activity to inhibit fibrosis in the hepatic stellate cell line HSC-T6 using Oil Red-O staining, which detects lipids that typically accumulate in quiescent hepatic stellate cells. A methanol extract with activity to stimulate accumulation of lipids was obtained. This extract was found to have PPARγ agonist activity using a luciferase reporter assay. After purification using several chromatographic methods, 6-ODA, a fatty acid with a triple bond, was identified as a candidate of PPARγ agonist. Synthesized 6-ODA and its derivative 9-octadecynoic acid (9-ODA), which both have a triple bond but in different positions, activated PPARγ in a luciferase reporter assay and increased lipid accumulation in 3T3-L1 adipocytes in a PPARγ-dependent manner. There is little information about the biological activity of fatty acids with a triple bond, and to our knowledge, this is the first report that 6-ODA and 9-ODA function as PPARγ agonists.

Notch signal protects non-parenchymal cells from ischemia/reperfusion injury in vitro by repressing ROS

Background. We have previously reported that Notch signaling pathway protects hepatocytes from ische-mia/reperfusion (I/R) injury by repressing reactive oxygen species (ROS) production. However, apart from hepatocytes, non-parenchymal cells including vascular endothelia cells, Kupffer cells and hepatic stellate cells are also reported to be involved in hepatic I/R injury.Aim. To clarify the role of Notch signaling in non-parenchymal cells subjected to I/R injury.Materials and methods. Human Umbilical Vein Endothelial Cells (HUVECs), mouse macrophage line RAW264.7 and rat hepatic stellate cell line HSC-T6 were cultured and subjected to I/R injury, respectively. Activation of Notch signaling was assessed by NICD western blot. Then, pharmacological inhibitor (γ-secretase inhibitor GSI) was used to block Notch signaling of related cell lines in vitro. Intracellular ROS was detected and analyzed by FACS and apoptosis was examined by TUNEL staining and Annexin V staining. Results. Notch signaling responded to I/R injury and I/R injury induced activation of Notch signaling in nonparenchymal cells. Notch signal deficiency led to overproduction of ROS and aggravated cell death of non-parenchymal cells subjected to I/R injury.Conclusion. Notch signal protectes non-parenchymal cells from I/R injury by repressing ROS.

Effect of neferine on hepatic stellate cells in Collagen-I, TIMP-1 and MMP-2

To observe the effect of neferine on Collagen-I, TIMP-1 and MMP-2 expressions and protein secretion of hepatic stellate cells. The hepatic stellate cell line HSC-T6 was cultured in vitro, and then randomly divided into 5 groups: the control group, the platelet-derived growth factor (PDGF) group and PDGF + neferine (2, 6, 10 micromol x L(-1)) groups. All of the groups were cultured for 48 h, and their cells were collected to extract mRNA and detect Collagen-I, TIMP-1 and MMP-2 expressions with RT-PCR. Their cell supernatants were also collected to determine the protein content of three factors with ELISA. Compared with the control group, PDGF could remarkably increase the Collagen-I, TIMP-1 and MMP-2 expressions and protein secretion of hepatic stellate cells. Compared with the PDGF group, PDGF + neferine (6, 10 micromol x L(-1)) groups showed a notable decrease in the Collagen-I and mRNA expression and protein secretion along with the increase in the concentration, whereas the PDGF + neferine (2 micromol x L(-1)) group showed no significant change in the Collagen-I and mRNA expression and protein secretion. Compared with the PDGF group, three PDGF + neferine groups showed no notable change in MMP-2 expression and protein secretion. Neferine can inhibit the Collagen-I, TIMP-1 and mRNA protein expression and protein secretion of PDGF-induced HSCs along with the increase in the concentration, but with not remarkable effect on the MMP-2 expression and secretion.

Short interfering RNA targetting NF-kappa B induces apoptosis of hepatic stellate cells and attenuates extracellular matrix production

Background Pharmacological inhibition of the NF-κB activity enhances hepatic stellate cell apoptosis and reverses experimental fibrosis. However, there is no report on the effects of NF-κB knockdown on apoptosis and extracellular matrix secretion in hepatic stellate cells. The aim of the present study is to explore the effects of siRNA targetting NF-κB on the apoptosis and extracellular matrix production in hepatic stellate cells. Methods The immortalised hepatic stellate cell line HSC-T6 was transfected with siRNA; 72 h later, cells were stimulated by LPS for 1 h; these cells were collected for further use. Hepatic stellate cell apoptosis was determined by fluorescence activated cell sorter analysis, TUNEL assay and caspase-3 activity measurement. Matrix metalloproteinase 2 activity was evaluated with Gelatin zymography. The quantities of mRNA transcriptions of NF-κB p65, type I collagen, tissue inhibitor of metalloproteinases-1, α-smooth muscle actin and transforming growth factor beta 1 and anti-apoptotic protein A1 were evaluated with quantitative reverse transcriptase real-time polymerase chain reaction. Results siRNA targetting NF-κB p65 effectively abrogated the expression of NF-κB p65 in hepatic stellate cells; decreased anti-apoptotic protein Bcl-2 and the mRNA transcription of hepatic type I collagen, α-smooth muscle actin, transforming growth factor beta 1, A1 and tissue inhibitor of metalloproteinases-1; increased matrix metalloproteinase 2 activity and promoted hepatic stellate cell apoptosis. Conclusion NF-κB knockdown enhances hepatic stellate cell apoptosis and attenuates extracellular matrix production.

Hsian-tsao ( Mesona procumbens Heml.) prevents against rat liver fibrosis induced by CCl 4 via inhibition of hepatic stellate cells activation

In this study, the protective effect of extract of Hsian-tsao ( Mesona procumbens) (EHT) against liver fibrogenesis in carbon tetrachloride (CCl 4)-injured rats was evaluated. The inhibitory effect of oleanolic acid (OA) and ursolic acid (UA), which are the active compounds in EHT, on the activation of hepatic stellate cells (HSC) was also determined. The results showed that EHT at a dosage of 1.2 g/kg of b.w. significantly reduced the liver injury induced by CCl 4 in rats. It also decreased the activity of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and the deposition of collagen in the liver. Oral administration of EHT reduced the levels of alpha-smooth muscle actin (α-SMA) and the activity of metalloproteinases (MMPs) in rats injured by treatment with CCl 4. In addition, we performed experiments with the rat hepatic stellate cell line HSC-T6 in which we induced the expression of MMP-2 and α-SMA with phorbol-12-myristate-13-acetate (PMA). Treating these cells with OA (20 μM) or UA (10 μM) caused a decrease in the levels of both proteins. Taken together, our data indicate that EHT can efficiently inhibit CCl 4-induced liver fibrosis in rats. EHT may therefore be a useful functional food for preventing liver fibrosis.

Construction of eukaryotic expression vector for rat Smad7 and its expression in hepatic stellate cell line HSC-T6

Construction of eukaryotic expression vector for rat Smad7 and its expression in hepatic stellate cell line HSC-T6

Induced hypothyroidism accelerates the regression of liver fibrosis in rats

It has been shown in previous studies that hypothyroidism prevents the development of liver fibrosis in bile duct ligated rats and in rats chronically treated with thioacetamide (TAA). In recent years, regression of liver fibrosis (occurring spontaneously or during treatment) has been demonstrated in rodent models such as bile duct ligation and CCl(4) administration. Therefore, in the present study, the potential therapeutic effect of hypothyroidism on liver fibrosis was investigated. Liver fibrosis was induced in rats by administration of TAA (200 mg/kg, i.p., twice weekly) for 12 weeks. Hypothyroidism was then induced by either methimazole (0.04%) or propylthiouracil (0.05%) administered in drinking water for 8 weeks. Control euthyroid rats received normal drinking water. Hypothyroidism was confirmed by a significant elevation of serum thyroid-stimulating hormone levels. Eight weeks after the cessation of TAA administration, spleen weight, histological score of liver fibrosis, and hepatic hydroxyproline content were significantly lower in both groups of hypothyroid rats as compared to euthyroid controls (P < 0.001). In vitro studies using the rat hepatic stellate cell line HSC-T6 using northern blot analysis and zymography, respectively, showed that high concentrations of triiodotyronine (T(3)) enhanced transforming growth factor (TGF)-beta-induced collagen I gene expression, and reduced metalloproteinase (MMP)-2 secretion, implying that reducing the levels of T(3) may contribute to resolution of fibrosis. Additionally, low T(3) concentration inhibited HSC-T6 proliferation. Pharmacologically induced hypothyroidism accelerates the resolution of liver fibrosis in rats. This beneficial effect may in part be due to prevention of T(3)-induced stimulation of collagen synthesis and reduction of MMP-2 secretion.

The role of IκBα in TNF-α-induced apoptosis in hepatic stellate cell line HSC-T6

The role of IκBα in TNF-α-induced apoptosis in hepatic stellate cell line HSC-T6