The research development of endothelial progenitor cells

Endothelial progenitor cell (EPC) is a kind of directional cell that is able to differentiate to endothelial cell. The role of EPC is associated not only with vasculogenesis during embryonic development but also with physiological organ maintenance and angiogenesis during postnatal and adult period. There is a good clinical therapeutic prospective use for EPC in the treatment of ischemia diseases and inhibition of tumor angiogenesis.     

3,4-Dihydroxyacetophenone reduces TG content in L02 cells and hepatic tissue via AMPK pathway

AIM: To investigate the mechanism of 3,4-dihydroxyacetophenone (3,4-DHAP) regulating lipid metabolism in human hepatic cells (L02 cells) and rabbit hepatic tissue. METHODS: L02 cells were divided into normal control group, model group, 3,4-DHAP group and simvastatin group. The cells were collected after treated with drugs for 8 h. Triglyceride (TG) content in the cells was detected by TG kit. RT-qPCR was applied to detect the mRNA expression level of AMP-activated protein kinase (AMPK). The protein levels of AMPK, phosphorylated AMPK (p-AMPK), phosphorylated sterol regulatory element binding protein-1c (p-SREBP-1c) and phosphorylated acetyl-CoA carboxylase (p-ACC) were detected by Western blot. Male New Zealand white rabbits (n=32) were randomized into normal control group, model group, 3,4-DHAP group and simvastatin group. The rabbits were treated with the drugs from week 2 to week 12. At the end of week 12, all rabbits were sacrificed. The liver lipids were measured by oil red O staining, and TG content was analyzed by TG kit. The protein levels of AMPK, p-AMPK, p-SREBP-1c and p-ACC in hepatic tissue were detected by Western blot. RESULTS: In L02 cells, compared with model group, TG content in 3,4-DHAP group was significantly decreased, and the expression of AMPK at mRNA and protein levels and the protein levels of p-AMPK, p-SREBP-1c and p-ACC were significantly increased. In rabbits of 3,4-DHAP group, the TG content was significantly decreased compared with model group, and the protein levels of AMPK, p-SREBP-1c and p-ACC were significantly increased. CONCLUSION: The AMPK signaling pathway may be involved in the mechanism of 3,4-DHAP to reduce TG content in L02 cells and rabbit hepatic tissue.     

Research progress and important scientific issues of organ fibrosis

Organ fibrosis is a common pathogenetic change of parenchymal organs under chronic conditions, characterized by increased fibrous connective tissues and reduced parenchymal cells. The essence of renal fibrosis is the "repair of scars" after renal tissue damage. It involves a loss of renal parenchyma cells, activation of myofibroblasts, deposition of extracellular matrix, imbalance of metabolism and abnormal interactions with organs. Hepatic fibrosis is a kind of repair response induced by various chronic hepatic diseases, including viral hepatitis and metabolic liver disease, and it is the common pathological basis of end-stage hepatic disease. Pulmonary fibrosis is a progressive and fatal inflammatory interstitial lung disease, characterized by inflammatory destruction and extracellular matrix deposition. Myocardial fibrosis is a process of pathological repair after a variety of injuries caused by hypertension, hypertrophic cardiomyopathy, viral cardiomyopathy, valve disorders, myocardial ischemia, diabetes, obesity and other metabolic abnormalities. Organ fibrosis indicates some common pathogenesis, but the exact mechanisms differ from organs and still need further investigation to identify biomarkers for early diagnosis and to devise drugs specifically for fibrosis. This article comprehensively summarizes the recent developments in organ fibrosis over the last 3 years, including underlying mechanisms and urgent scientific issues remained.     

Effect of peroxynitrite anion (ONOO-) on the development of hepatic fibrosis

AIM: To explore the effect of peroxynitrite anion (ONOO-) on development of hepatic fibrosis. METHODS: The hepatic fibrosis (HF) of Wistar rats was established by giving complex pathogens. The rats were intra-gastrically infused with 0.9% salt (1.5 mL/d) and inhibitor of nitric oxide synthase (NOS), L-NNA (20 mg·kg－1·d－1), respectively. At the end of the 4th week, the levels of plasma LPS and NO2-/NO3- were detected. The expression of nitrotyrosine (NT) in hepatic tissue was examined by immunohistochemical techniques. The degree of hepatic fibrosis was observed by VG staining. RESULTS: The level of plasma NO in HF+NNA group was remarkably lower than that in HF group (P<0.01). The expression of NT in hepatic tissue was the strongest and the degree of hepatic fibrosis was the most serious in HF group. CONCLUSION: ONOO- promotes the development of hepatic fibrosis.     

Role of SIRT1/AMPK pathway in early intervention of Lira alleviating non-alcoholic fatty liver disease caused by high-fat diet in rats

AIM To investigate the effect of early intervention of glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide (Lira) on oxidative stress, glucose tolerance, hepatic steatosis and insulin resistance of the rats with high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD), and to explore the role of silent information regulator 1 (SIRT1)/AMP-activated protein kinase (AMPK) signaling pathway in this process. METHODS Twenty-four male SD rats were randomly divided into normal diet (ND) group, HFD group and HFD+Lira group, with 8 rats in each group. After 1 week of adaptive feeding, the rats in HFD+Lira group were subcutaneously injected with Lira (200 μg/kg) per day at a fixed time point, while the rats in the remaining 2 groups were injected with normal saline at the same volume. During the intervention, the body weight, hair, appetite, defecation and activity of the rats were observed to adjust the dosage timely. The body weight, food intake and blood glucose were recorded weekly. Glucose tolerance test was performed at the end of the 16th week. At the end of the 18th week, hyperinsulinemic euglycemic clamp test was conducted after anesthesia. Blood was taken from the carotid artery. The liver and adipose tissues from different parts were taken after death. The serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and other indicators were detected. HE staining was used to observe the pathological changes of the liver tissue. Lipid accumulation in the liver tissues was observed by oil red O staining. Liver fibrosis was observed by Masson staining and Sirius red staining. Fluorescence staining for reactive oxygen species (ROS) was used to observe the oxidative stress in the liver. The expression of GLP-1 receptor in the liver was observed by immunofluorescence staining. The expression and localization of SIRT1 and phosphorylated AMPK at Thr172 [p-AMPK (Thr172)] were observed by immunohistochemical staining. The protein levels of AMPK, p-AMPK (Thr172), SIRT1, phosphorylated sterol regulatory element binding protein-1c at Ser372 [p-SREBP-1c (Ser372)], phosphorylated acetyl coenzyme A carboxylase at Ser79 [p-ACC (Ser79)], carnitine palmitoyltransferase 1A (CPT1A) and fatty acid synthase (FAS) in liver tissues were determined by Western blot. RESULTS The results of HE and oil red O staining of rat liver tissues in HFD group confirmed the structural disorder and serious lipid accumulation, while Masson and Sirius red staining showed severe fibrosis, suggesting the successful establishment of NAFLD rat model. Compared with ND group, the levels of total cholesterol (TC), triglyceride (TG), AST and ALT in serum, and the levels of malondialdehyde (MDA), TC, TG and ROS in liver tissues in HFD group were significantly increased (P<0.01), while the activity of superoxide dismutase (SOD) was decreased (P<0.01). The protein levels of p-AMPK (Thr172), SIRT1, p-SREBP-1c (Ser372), p-ACC (Ser79) and CPT1A in the liver tissues were significantly reduced (P<0.05 or P<0.01), while the expression of FAS was increased （P<0.01）. Compared with HFD group, lipid accumulation and fibrosis in the liver tissues of the rats in HFD+Lira group were significantly attenuated, the serum levels of TC, TG, AST and ALT, and MDA, TC, TG and ROS in liver tissues were markedly reduced (P<0.05 or P<0.01), while SOD activity was increased (P<0.05). The protein levels of p-AMPK (Thr172), SIRT1, p-SREBP-1c (Ser372), p-ACC (Ser79) and CPT1A in the liver tissues were significantly increased (P<0.05 or P<0.01), while the expression of FAS was decreased （P<0.01）. CONCLUSION Lira attenuates insulin resistance, oxidative stress and fibrosis, and improves liver lipid metabolism in the rats with NAFLD induced by HFD, which may be mediated by SIRT1/AMPK signaling pathway.     

Yunpiheluo decoction alleviates diabetic kidney injury by regulating Sirt1/AMPK signaling pathway and activating autophagy

AIM: To observe the effect on Yunpiheluo decoction (YPHL) on renal injury in type 2 diabetic rats and to explore the mechanism from the perspective of Sirt1-AMPK-autophagy. METHODS: Male Zucker diabetic fatty (ZDF) rats (n=24) were randomly divided into model group, Sirt1 over-expression group and YPHL group, and fed with high-fat and high-sugar diet for 10 weeks. ZL rats were used as normal control and fed with normal diet for 10 weeks. After 10 weeks, urine and blood were collected for renal function detection. The rats were sacrificed and specimen was submitted. In addition, the mRNA expression of Sirt1 was analyzed by real-time PCR. The protein levels of Sirt1, AMPK, p-AMPK, LC3 and P62 in the renal tissues wene determined by Western blot. The renal pathological changes were observed under light microscope with HE and Masson staining. RESULTS: Compared with control group, fasting blood glucose (FBG), urinary protein (UP), urinary albumin (U-ALB) and serum creatinine (SCr) in model group were obviously increased (P<0.01). The mRNA expression of Sirt1 was decreased (P<0.05). The protein levels of SIRT1, AMPK, p-AMPK and LC3-II/-I were decreased (P<0.01), and P62 was increased (P<0.01). Glomerular focal fibrosis, focal renal tubular epithelial cell vacuolation, necrosis, shedding and atrophy, tubular type, and renal interstitial fibrosis were observed. Compared with model group, FBG was obviously decreased in Sirt1 over-expression group (P<0.01), but it showed no significant change in YPHL group (P>0.05). SCr and U-ALB were decreased (P<0.05), Sirt1 mRNA was increased (P<0.05), the protein levels of SIRT1, AMPK, p-AMPK and LC3-II/-I were increased (P<0.01), and P62 was decreased (P<0.01) in Sirt1 over-expression group and YPHL group. HE and Masson staining showed that the renal damage in Sir1 over-expression group and YPHL group was attenuated. CONCLUSION: Yunpiheluo decoction may protect the kidney by increasing the expression level of Sirt1, activating AMPK, and regulating autophagy.     

Role of resistin in hepatic insulin resistance and the underlying mechanism

AIM: To investigate the role of resistin in hepatic insulin resistance and its mechanism. METHODS: A mouse model of hyperresistinemia in C57BL/6 mice was established by intravenous administration of the recombinant adenovirus encoding mouse resistin. Using periodic acid-Schiff staining we observed the effects of resistin on hepatic glycogen storage. Western blotting was used to measure AMPK-α protein and phosphrylated AMPK-α (Thr172) protein. mRNA levels of phosphoenolpyruvate carboxykinase gene and glucose-6-phosphatase gene were measured by real-time PCR. RESULTS: On day 5 after Adv injection, the concentration of plasma resistin was much higher in Adv-resistin-EGFP-treated mice than that in saline- or Adv-EGFP-treated mice. Semiquantitation of hepatic glucogen storage by PAS showed that the mice with hyperresistinemia had decreased glycogen particles compared to normal control and Adv-EGFP groups. The ratio of phosphorylated AMPK (Thr172)-α to total AMPK-α was used to evaluate hepatic AMPK activation. Compared with normal control and Adv-EGFP groups, the Adv-resistin-EGFP-treated mice had significantly lower ratio of p-AMPK/AMPK, and higher expression levels of G6Pase and PEPCK mRNA in liver. CONCLUSION: Resistin may decrease AMPK activation with downregulating expression of gluconeogenic enzymes, resulting in increased glucose production and decreased hepatic glycogen storage. Resistin may play an important role in hepatic insulin resistance.     

Dynamic expression of PTEN in liver tissue of rats with hepatic fibrosis

AIM: To investigate the dynamic expression of phosphatase and tensin homolog deleted on chromosome ten (PTEN) in liver tissue in the process of hepatic fibrosis in rats. METHODS: The rat model of hepatic fibrosis used in this study was induced by common bile duct ligation (BDL). Hematoxylin and eosin (HE) and Masson’s trichrome staining were used for observing the histological changes in hepatic fibrosis tissue. At 4 time points, the expressions of PTEN protein and mRNA in hepatic tissues of rats were detected by immunohistochemical staining, Western blotting and real-time fluorescent quantitative PCR assay, respectively. RESULTS: The rat model of hepatic fibrosis was established successfully. With each consecutive week after BDL, increased fibrosis, degeneration and necrosis were found in rat liver cells. Not surprisingly, a disruption of normal architecture and a decrease in normal hepatic cells was concomitantly observed. The immunohistochemical staining indicated that there was extensive expression of PTEN in liver tissues of normal rats, it expressed mainly in the cytoplasm, and with the aggravation of hepatic fibrosis, the expression of PTEN in liver tissues decreased gradually (P<0.01). Western blotting and real-time fluorescent quantitative PCR at weekly time points (1, 2, 3, and 4 weeks) after BDL showed that, the expression of PTEN protein and mRNA in fibrotic rat liver tissue decreased gradually with increasing severity of hepatic fibrosis (P<0.01). Furthermore, all values from BDL rats were significantly lower than those from the sham operation group (P<0.01). CONCLUSION: The expressions of PTEN protein and mRNA in fibrotic liver tissue of rat decrease gradually with the progression of hepatic fibrosis, and increasing severity of fibrosis correlated well with decreasing PTEN expression.     

Role of miR-219 and TGFBR2 in pathogenesis of renal fibrosis

AIM:To study the role of microRNA-219 (miR-219) in regulation of transforming growth factor-β receptor type 2 (TGFBR2) in renal fibrosis. METHODS:The renal fibrosis patients (n=70) were selected in this stu-dy, and 20 cases of healthy people were selected as control group. RT-qPCR was used to detect the expression of miR-219 in the serum of the patients with renal fibrosis and control group, and the expression of miR-219 in NRK49F cells after stimulation with angiotensin Ⅱ(AngⅡ) was detected. The protein expression of α-smooth muscle actin (α-SMA) in the NRK49F cells transfected with miR-219 mimics after stimulation with AngⅡ was determined by Western blot. The potential target gene TGFBR2 of miR-219 was screened and verified by the method of luciferase reporter gene. RT-qPCR and Western blot were used to detected the effect of miR-219 mimics on the expression of TGFBR2 at mRNA and protein levels, and the mRNA expression of α-SMA, connective tissue growth factor (CTGF), type I collagen α1 (COL1A1) and COL3A1 in the NRK49F cells was also detected, respectively. The unilateral ureteral occlusion (UUO) mouse model was established and the expression of miR-219 in the renal tissue was monitored. The morphological change of renal fibrosis was observed in the UUO mice after injection of miR-219, and the mRNA expression levels of COL1A1 and COL3A1 were detected. RESULTS:The expression level of miR-219 in the patients with renal fibrosis was significantly lower than that in control group, and the expression of miR-219 in the UUO mice was decreased significantly (P<0.01). The expression level of miR-219 was significantly decreased in the NRK49F cells after AngⅡ stimulation, and miR-219 mimics inhibited the protein expression of α-SMA(P<0.01). miR-219 mimics had a targeted regulatory effect on TGFBR2 gene, which inhibited the mRNA and protein expression of TGFBR2. miR-219 mimics inhibited the mRNA expression of α-SMA, CTGF, COL1A1 and COL3A1. miR-219 also down-regulated the mRNA expression of COL1A1 and COL3A1 in the UUO mice and inhibited the process of renal fibrosis. CONCLUSION:miR-219 inhibits the development of renal fibrosis by inhibiting the expression of TGFBR2, which may become a new target for the diagnosis and treatment of renal fibrosis.     

Effect of glucagon-like peptide 1 on Sesn2/AMPK/mTOR signaling pathway in liver of obese rats induced by high-fat diet

AIM: To explored the effect of glucagon-like peptide 1 receptor agonist liraglutide on Sesn2/AMPK/mTOR signaling pathway in the liver of obese rats.METHODS: Male SD rats were divided into normal chow (NC) group (n=12) and high-fat diet (HF) group (n=33). After 12 weeks, 5 rats of each group were used to assess establishment of obese rat model. The rats in HF group were divided into 4 subgroups, HF group, low dose of liraglutide (LG) group, middle dose of liraglutide (MG) group, and high dose of liraglutide (HG) group, and treated with various doses of liraglutide (0, 50, 100 and 200 μg/kg) via hypodermic injection twice a day for 4 weeks. The body weight and epididymal fat index of the rats at the 16th week were measured. The liver tissue fatty degeneration was observed. The protein levels of Sesn2, AMPK, p-AMPK, mTOR and p-mTOR were determined by Western blot.RESULTS: The body weight of rats in HF group was obviously higher than that in NC group (P<0.01). Compared with NC group, the levels of Sesn2 and p-AMPK/AMPK were significantly decreased in HF group (P<0.01), while the level of p-mTOR/mTOR was not changed. After treatment with liraglutide for 4-week, the body weight of the rats in LG, MG and HG groups was obviously lower than that in HF group (P<0.01), and epididymal fat index of the rats in MG and HG groups was obviously lower than that in HF group (P<0.01). The protein level of Sesn2 in HG group was obviously higher than that in HF group (P<0.01). The level of p-AMPK/AMPK was significantly increased in MG and HG groups (P<0.01). The level of p-mTOR/mTOR was significantly increased decreased in LG, MG and HG groups (P<0.01).CONCLUSION: Glucagon-like peptide 1 receptor agonist liraglutide affects energy metabolism and improves the state of obesity through Sesn2/AMPK/mTOR signaling pathway.     

p300/p53/Smad3 pathway involved in aging-related atrial fibrosis in human atrial fibroblasts

AIM To investigate the role of p300 in aging-related atrial fibrosis in human atrial fibroblasts （HAFs） and its potential mechanism. METHODS HAFs were obtained from human left atrial tissue, and the senescence model was established by cell passage. Senescence-associated β-galactosidase （SA-β-Gal） staining was used to detect the cell senescence, and Western blot was used to determine the protein levels of p300, p53, Smad3 and other senescence and fibrosis associated proteins in HAFs. RESULTS Compared to passage 3 HAFs, the proportion of senescent cells, and the protein levels of p300, p53, p-Smad3 and other senescence and fibrosis associated proteins were increased in HAFs at passage 7 and 11 （P<0.05）. After treated with curcumin （a p300 inhibitor） or transfection with p300 small-hairpin （sh） RNA plasmid, the protein levels of p300, and the senescence and fibrosis associated proteins were decreased in HAFs at passage 7（P<0.05）. Up-regulation of p300 by transfection with p300 over-expression plasmid increased the protein levels of p53, Smad3 and MMP-2 in HAFs at passage 3 （P<0.05）. CONCLUSION p300/p53/Smad3 signaling pathway plays an important role in aging-related atrial fibrosis in HAFs.     

Distinct effects of different β-adrenoceptor stimulation patterns on car-diac AMP-activated protein kinase activity

AIM: To investigate the cardiac AMP-activated protein kinase (AMPK) activity and the effects of AMPK activator on cardiac structure and function in the mice with different β-adrenoceptor (β-AR) stimulation patterns. METHODS: Male BALB/c mice were subcutaneously injected with AMPK activator (AICAR, 250 mg· kg^-1·d^-1) or saline, and infused with β-AR agonist isoproterenol (ISO, 5 mg·kg^-1·d^-1) for 14 d. The cardiac functions were evaluated by echocardiography or hemodynamic method, and the hearts were harvested after infusion cessation immediately or 3 d later. Phosphorylated AMPK (p-AMPK) was measured by Western blot. RESULTS: Sustained ISO infusion increased p-AMPK level. AICAR did not further increase p-AMPK but attenuated ISO-induced increase in heart weight. Sustained ISO infusion increased cardiac systolic function as indicated by left ventricular fractional shortening (FS) and maximum rate of pressure rise (+dp/dt_max). The cardiac systolic function was not further increased by AICAR. The cardiac diastolic function as indicated by left ventricular end-diastolic pressure (LVEDP) was not different in each group. In contrast, cardiac p-AMPK level was similar between the control mice and the mice with sustained ISO infusion and ceased infusion for 3 d. In this model, AICAR improved the cardiac systolic and diastolic functions, which were impaired by ISO. Moreover, the increased pattern of p-AMPK level was similar with that of heart rate upon ISO stimulation. CONCLUSION: Sustained ISO infusion increases p-AMPK. After ISO infusion cessation for 3 d, p-AMPK is decreased to the basal level. β-AR-induced inotropic effects should be avoided to investigate the cardioprotective role of AMPK activation in the β-AR stimulation models.     

The phenotypic-change characteristics of renal residential cells and its roles in the development of renal diseases

Increasing evidence has proved that phenotypic changes occured in residential renal cells during the process of renal diseases. The phenotypic change of mesangial cell plays a key role in the development of glomerular sclerosis, while the phenotypic changes of tubulo-interstitial cells have close relationship with the progress of interstitial fibrosis. Understandings of these phenotypic changes and their regulations may help us know better of the mechanism of renal diseases and find out ways to block the disease development.     

Role of IL-33/ST2 signaling pathway in fibrosis diseases

Interleukin (IL)-33 is a member of IL-1 family. It is identified as a functional ligand for ST2 which is an IL-1 receptor-like protein. IL-33/ST2 signaling is involved in T-cell-mediated immune responses. Increasing evidence indicates that IL-33 has different roles in different diseases. Recently, some studies have demonstrated that IL-33 may be related to the genesis and development of fibrosis diseases. We review current knowledge of the biological characteristics of IL-33 and the role of IL-33/ST2 signaling pathway in fibrosis diseases.     

Effect of arsenic trioxide on bleomycin-induced pulmonary fibrosis in rats

AIM: To observe the effect of arsenic trioxide (ATO) on bleomycin-induced pulmonary fibrosis in rats. METHODS: Pulmonary fibrosis was induced in Sprague-Dawley (SD) rats by intratracheal instillation of bleomycin (BLM). The rats in ATO treatment group, steroid treatment group and model group were intraperitoneally injected with ATO, dexamethasone or normal saline (NS), respectively, while the control rats received NS both intratracheally and intraperitoneally. The effects of ATO were evaluated by analyzing the median survival time, hydroxyproline level in the lung, semi-quantitative grading of alveolitis and pulmonary fibrosis, and quantitative analysis of the collagen in lung tissue (Masson’s trichrome staining). Apoptosis index (AI) of the lung was detected by using the terminal transferase dUTP-digoxygenin nick end-labeling (TUNEL) method. The results of immunohistochemical staining for some cytokines were quantitatively analyzed. RESULTS: ATO (1) prolonged the median survival time of rats with BLM-induced pulmonary fibrosis at some extent; (2) attenuated the alveolitis and pulmonary fibrosis, reduced hydroxyproline level and collagen deposition in the lung tissue; (3) increased the AI of lung tissue at a certain phase; and decreased the levels of transforming growth factor-β1 (TGF-β1) and tissue inhibitor of metalloproteinase-1 (TIMP-1), increased the content of interferon-γ (IFN-γ), but did not influence the concentration of matrix metalloproteinase-9 (MMP-9) significantly. CONCLUSION: ATO might attenuate BLM-induced pulmonary fibrosis in rats via increasing the AI in the lung tissue.     

Renal tubular epithelial-mesenchymal transition in kidney fibrosis

Epithelial-mesenchymal transition (EMT), a process by which differentiated epithelial cells undergo a phenotypic conversion that gives rise to the matrix-producing fibroblasts and myofibroblasts, is increasingly recognized as an integral part of tissue fibrogenesis after injury. However, the degree to which renal tubular epithelial EMT contributes to kidney fibrosis remains a matter of intense debate and is likely to be context-dependent. Renal tubular EMT is an adaptive response of epithelial cells to a hostile or changing microenvironment and is regulated by many factors. Several intrace-llular signal transduction pathways such as transforming growth factor-β (TGF-β)/Smad and Wnt/β-catenin signaling are essential in controlling the process of renal tubular epithelial EMT which are potential targets of antifibrotic therapy presently. This review highlights the current understanding of renal tubular epithelial EMT and its underlying mechanisms to stimulate further discussion on its role in the pathogenesis of renal interstitial fibrosis.     

Changes of endoplasmic reticulum stress-related molecules CHOP and TRB3 in rat fibrotic liver

AIM: To observe the changes of endoplasmic reticulum stress-related molecules CCAAT/enhancer-binding protein homologous protein(CHOP) and Tribbles homolog 3（TRB3） in the process of liver fibrosis induced by carbon tetrachloride (CCl4). METHODS: Male Wistar rats weighing 180 g to 200 g were divided into 4-week normal control group, 8-week normal control group, 4-week liver fibrosis group and 8-week liver fibrosis group. The rats in liver fibrosis groups were induced by subcutaneous injection of 40% CCl4 for 4 weeks or 8 weeks. The pathological changes of the liver were observed under light microscope. The protein level of ATF6 was determined by Western blotting. The protein and mRNA levels of CHOP and TRB3 in the liver were analyzed by immunohistochemistry, Western blotting and real-time PCR, respectively. The apoptosis of hepatocytes was measured by TUNEL assay. RESULTS: Pseudolobuli formed in the liver tissue of hepatic fibrotic rats. Compared with the control rats, the protein level of p90ATF6 was obviously decreased, the protein level of p50ATF6 was obviously increased, and the protein and mRNA levels of CHOP and TRB3 were obviously higher in the hepatocytes of hepatic fibrotic rats. The apoptosis of hepatocytes was also increased in 4-week and 8-week fibrosis groups. CONCLUSION: In the process of liver fibrosis induced by 40% CCl4, the obviously increased expression of endoplasmic reticulum stress-related molecules CHOP and TRB3 at protein and mRNA levels indicates that endoplasmic reticulum stress may play an important role in the liver fibrosis by promoting the apoptosis of hepatocytes.     

Repair effect of purple sweet potato anthocyanin on intestinal barrier injury in mice with ulcerative colitis induced by DSS

AIM To explore the repair effect of purple sweet potato anthocyanin on intestinal barrier injury of ulcerative colitis mice induced by dextrin sulfate sodium （DSS）. METHODS The mice were randomly divided into normal drinking group， DSS model group， different doses of purple sweet potato anthocyanin （12.5， 25， 50 and 75 mg/kg） groups， and 5-aminosalicylic acid （5-ASA） positive drug control group. Except using normal drinking water for control group， the mice in the other groups were treated with 2.5% DSS in drinking water for 7 days to induce the ulcerative colitis model. The mice in purple sweet potato anthocyanin treatment group and the 5-ASA positive drug control group were given the drug by intragastric gavage on the first day of modeling. The body weight of the mice and the hematocheziawere recorded every day. After continuous administration for 8 days， the mice in each group were killed and colon tissue was retained. Immunohistochemical technique （IHC） was used to detect the expression of tight junction protein ZO-1 and occludin and inflammatory factors tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） in the colon of mice. The expression of mucin in goblet cells of colon tissue was observed by glycogen PAS staining. The protein expression of ZO-1， occludin， TNF-α were determined by Western blot， Sirius red staining was used to detect colonic fibrosis in mice. RESULTS Compared with control group， the disease activity index and histological injury of DSS model mice were significantly increased（P<0.01）. Compared with model group， the disease activity index scores of the mice in different dose groups of purple sweet potato anthocyanin were decreased. The expression and distribution of ZO-1 and occludin in colon tissues were increased， and the expression and distribution of TNF-α and IL-6 in colon tissues were decreased. Glycogen PAS staining showed a significant increase in the distribution and expression of mucin in goblet cells of colon tissues in the purple sweet potato anthocyanin treatment group. Sirius red staining also showed that the degree of fibrosis in the purple sweet potato anthocyanin treatment groups was lower than that in model group. CONCLUSION Purple sweet potato anthocyanins has therapeutic effect on ulcerative colitis in mice induced by DSS， mainly through up-regulating the expression of tight junction proteins ZO-1 and occludin， to protect the integrity of intestinal barrier， inhibiting the expression of inflammatory cytokines TNF-α and IL-6 and intestinal fibrosis， to suppress the development of colonic inflammation.     

Effect of galectin-3 on ventricular remodeling in rabbits with ischemic cardiac insufficiency

AIM:To investigate the relationship between galectin-3(Gal-3) and myocardial fibrosis,and to clarify the role of Gal-3 in ventricular remodeling in rabbits with ischemic cardiac insufficiency.METHODS:A rabbit model of ischemic cardiac insufficiency was established by ligation of the anterior descending branch of the coronary artery.The 20 rabbits were randomly divided into sham operation group and cardiac insufficiency group by random number table method.After 4 weeks of coronary artery ligation,the cardiac function was measured by cardiac echocardiogram.Real-time PCR and Western blot were used to detect the expression of Gal-3,type I collagen and type Ⅲ collagen at mRNA and protein levels in the myocardium.The serum Gal-3 contents were measured by ELISA.HE staining and Masson staining were used to observe the degree of fibrosis development in myocardial tissues after infarction.RESULTS:Compared with sham operation group,the mRNA expression of Gal-3 in cardiac insufficiency group was significantly increased.At the same time,type I collagen,type Ⅲ collagen and collagen type I/Ⅲ ratio were also increased significantly.The protein contents of Gal-3,type I collagen and type Ⅲ collagen were increased significantly.The serum Gal-3 levels were significantly increased.The pathological changes were observed in cardiac insufficiency group as the myocardial cell morphological disorder and marked hyperplasia of fibrous tissue were seen.CONCLUSION:Gal-3 aggravates myocardial fibrosis in rabbits with ischemic cardiac insufficiency,and promotes the ventricular remodeling and the occurrence of heart failure.     

Role of 78 kD glucose-regulated protein in the development of liver cirrhosis promoted by intestinal endotoxemia in rats

AIM: To explore the role of 78 kD glucose-regulated protein (GRP78) in the development of liver cirrhosis in rats promoted by intestinal endotoxemia (IETM). METHODS: Fifty-one male Wistar rats were randomly divided into liver cirrhosis groups of 4th-week, 6th-week and 8th-week, and normal control group at the corresponding time points. The rat model of hepatic cirrhosis was induced by employing multiple pathogenic factors to the animals. The liver injury and hepatic fibrosis were observed with the staining of HE and VG, respectively. The expression of GRP78 at the mRNA and protein levels was measured by the methods of RT-PCR and immnunohistochemistry, respectively. The concentrations of alanine aminotransferase(ALT), endotoxin, TNF-α and homocystine (HCY) in plasma, and the content of TNF-α, malondialdehyde(MDA) and PⅢP in liver tissues were detected. RESULTS: As liver cirrhosis developed, the levels of ALT, endotoxin, TNF-α and HCY in plasma, the expression of GRP78 at mRNA and protein, the content of TNF-α, MDA and PⅢP in liver tissues, and the index of liver fibrosis were gradually increased and were significantly higher than those in normal control group (P<0.05). Elevated endotoxin in plasma was correlated positively with the protein expression of GRP78, the content of MDA and HCY in plasma and the index of liver fibrosis (P<0.01). Elevated protein expression of GRP78 was correlated positively with the content of MDA and HCY in plasma and the index of liver fibrosis (P<0.01). CONCLUSION: GRP78 plays an important role in the development of liver cirrhosis. Endoplasmic reticulum stress is a possible mechanism in the development of liver cirrhosis promoted by IETM.