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.     

Role of GRP78 in alteration of myocardium induced by intestinal endotoxemia in cirrhotic rats

AIM: To explore the role of glucose-regulated protein 78 (GRP78) in the alteration of myocardium induced by intestinal endotoxemia in cirrhotic rats. METHODS: Fifty-one male Wistar rats were randomly divided into liver cirrhosis groups of 4-week, 6-week and 8-week, and normal control groups at corresponding time points. The cardiac functions of the 8-week rats were measured. Tumor necrosis factor α(TNF-α) and malondialdehyde(MDA) in myocardial tissues were detected. The number of myocardial cells and the collagen volume fraction (CVF) were determined with toluidine blue and van Giesan staining, respectively. The expression of GRP78 and hypoxia-inducible facotr 1α(HIF-1α) was analyzed by the method of immnunohistochemistry. RESULTS: Compared with normal control group at corresponding time point, left ventricular end-diastolic pressure(LVEDP) and ±LV dp/dt_max in 8-week group were significantly decreased (P<0.05). The levels of TNF-α, MDA and CVF, the protein expression of GRP78 and HIF-1α in the myocardial tissues were significantly increased in every model group (P<0.05), and the number of myocardial cells was gradually decreased (P<0.05). Elevated levels of endotoxin in plasma were positively correlated with the levels of alanine aminotransferase (ALT),homocysteine (Hcy) and TNF-α in plasma, the levels of TNF-α, MDA and CVF, and protein levels of GRP78 and HIF-1α in the myocardial tissues (P<0.05). Elevated protein expression of GRP78 in the myocardial tissues was positively correlated with the levels of ALT, Hcy in plasma and MDA, CVF, HIF-1α protein in the myocardial tissues (P<0.05). CONCLUSION: Intestinal endotoxemia induced by liver cirrhosis may directly or indirectly lead to endoplasmic reticulum stress and overexpression of GRP78. GRP78 may be a key molecule in the pathogenesis of myocardial remodeling and functional alteration induced by liver cirrhosis.     

Effects of macrophage polarization during development of liver cirrhosis in rats

AIM: To explore the state of macrophage polarization and its relation with intestinal endotoxemia-endoplasmic reticulum stress in the development of liver cirrhosis induced by multiple pathogenic factors in rats. METHODS: The male SD rats (n=36) were randomly divided into normal control group and liver cirrhosis model group, and sacrificed at the end of the 4th, 6th and 8th weeks. The rat model of liver cirrhosis was induced by multiple pathogenic factors. The levels of alanine aminotransferase (ALT), endotoxin, homocysteine (Hcy) in the plasma, and inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), arginase-1 (Arg-1) and interleukin-10 (IL-10) in the liver tissues were detected by ELISA. Histopathological change of the liver was observed under microscope with the staining of hematoxylin and eosin (HE) and van Gieson (VG). The expression of glucose-regulated protein 78 (Grp78), nuclear factor-kappa B (NF-κB), interferon-regulatory factor 5 (IRF5), CD86, CD206 and transforming growth factor-β1 (TGF-β1) at mRNA levels in the liver tissues were detected by the method of real-time fluorescence quantitative PCR.RESULTS: Compared with the corresponding normal control group, the levels of ALT, endotoxin, Hcy in the plasma and Grp78 mRNA in the liver tissues in liver cirrhosis model group were significantly and gradually increased (P<0.05). The mRNA expression of NF-κB, IRF5 and CD86, and the protein levels of iNOS, TNF-α and IL-6 in the liver tissues were significantly increased (P<0.05), and they successively increased from the 4th week to the 6th week and decreased reversely at the 8th week. The mRNA expression of CD206, TGF-β1, Arg-1 and IL-10 in the liver tissues were significantly increased from the 6th week to the 8th week (P<0.05), and no significant difference at the 4th week was observed. The level of endotoxin in the plasma was correlated with the mRNA expression of Grp78 in the liver tissues (P<0.01). Both endotoxin in the plasma and Grp78 mRNA in the liver tissues were correlated with the mRNA expression of CD86 and CD206 in the liver tissues (P<0.01).CONCLUSION: The pathway of liver damage-intestinal endotoxemia-endoplasmic reticulum stress-macrophage polarization may be critical in the pathogenesis of liver cirrhosis induced by multiple pathogenic factors.     

Role of glucose-regulated protein 78 in pulmonary microvascular remodeling during development of rat hepatopulmonary syndrome

AIM：To explore the mechanisms of pulmonary microvascular remodeling induced by glucose-regulated protein 78 (GRP78) in the development of hepatopulmonary syndrome (HPS) in rats. METHODS：The Wistar rats were randomly divided into HPS groups at the 4th, 6th and 8th weeks, and normal control groups at the corresponding time points. The rat model of HPS produced in the process of liver cirrhosis was induced by employing multiple pathogenic factors to the animals. The rats in normal control group were designed by feeding with standard diet and mineral water. The expression of GRP78, factor Ⅷ- related antigen (FⅧ-RAg), C/EBP homologous protein (CHOP, also called growth arrest and DNA damage-inducible protein 153, GADD153), caspase-12, Bcl-2 and nuclear factor (NF)-κB in the lung tissues were measured by immunohistochemistry. The expression of VEGF at mRNA and protein levels in the lungs was measured by the methods of RT-PCR and Western blotting, respectively. RESULTS：The expression of GRP78, FⅧ-RAg,VEGF and Bcl-2 proteins was gradually increased with the HPS development. The protein expression of NF-κB was also gradually increased, especially in nucleus. GRP78 protein in the lung was positively correlated with the expression of FⅧ-RAg and VEGF, but negatively correlated with the expression of CHOP/GADD153 and caspase-12. The protein levels of GRP78 and FⅧ-RAg, and VEGF at both mRNA and protein levels were higher, and the protein levels of CHOP/GADD153 and caspase-12 were lower in the rats with HPS at every time point than those in normal control rats (P<0.05). CONCLUSION：Overexpression of GRP78 in the lung may be the critical pathogenesis of HPS by promoting cell survival and proliferation, and inhibiting cell apoptosis, thus leading to pulmonary microvascular remodeling.     

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《园艺学报》是中国园艺学会和中国农业科学院蔬菜花卉研究所主办的学术期刊,创刊于1962年,刊载有关果树、蔬菜、观赏植物、茶及药用植物等方面的学术论文、研究报告、专题文献综述、问题与讨论、新技术新品种以     

Effects of imidapril on blood gas,oxidative stress and inflammatory factors in rats with acute lung injury induced by ammonium chloride

AIM: In this study, the rat lung injury model was induced by ammonium chloride for studying the effect of imidapril on blood gas, serum TNF-α, IL-6 and MDA concentrations, and AngⅡ and CD54 protein expression in rat lung tissue. METHODS: Male rats were randomly divided into 3 groups: control group, lung injury model group and drug group. The rats in control group were given saline (2 mL/kg), while the rats in lung injury model group were given 6% ammonium chloride (2 mL/kg). In drug group, imidapril (3 mg·kg^-1·d^-1) was given to the rats once daily for 1 week by intragastric gavage after given 6% ammonium chloride. On the 7th day, the rats were anesthetized with 2% so-dium pentobarbital. Abdominal aorta blood, venous blood and lung tissue were collected. The blood gas indexes and serum TNF-α, IL-6 and MDA concentrations were determined. The lung tissues were fixed and sliced, and the expression of AngⅡ and CD54 proteins was detected by immunohistochemistry. RESULTS: The PaCO₂ increased in lung injury model group compared with control group and drug group (P < 0.05).The expression of AngⅡ and CD54, and the concentrations of TNF-α, IL-6 and MDA also increased significantly (P < 0.01) in model group. Pulmonary edema, inflammation, alveolus congestion, hemorrhage and hyperplasia in model group were obvious compared with control group and drug group. CONCLUSION: Imidapril improves blood gas indexes, and reduces lipid peroxidation and inflammatory responses in the rats with lung injury induced by ammonium chloride.     

Protective effect of emodin on lung injury induced by hepatic fibrosis in rats

AIM:To explore the protective effect of emodin on lung injury induced by hepatic fibrosis in rats. METHODS:The hepatic fibrosis rat model was established with multiple pathogenic factors (CCl 4, ethanol, high fat, high cholesterol and low choline) and treated with different doses (20 mg/kg and 40 mg/kg) of emodin for 4 weeks. The hepatic index was measured. The biochemical indexes, endotoxin, homocysteine, albumin, aspartate aminotransferase,alanine aminotransferase, total bilirubin, total cholesterol and triglyceride, and hepatic fibrosis indexes, hyaluronic acid, laminin, collagen IV and procollagen Ⅲ, were detected. The histopathological changes of the liver were observed. The pulmonary index was determined. The histopathological changes of the lungs were observed. The levels of tumor necrosis factor α (TNF-α), malondialdehyde (MDA), nitric oxide (NO) and peroxynitrite (ONOO-) in the lung tissues were analyzed. RESULTS:The rat hepatic fibrosis model was successfully established. In model group, lung edema and inflammation occurred, and the pulmonary index and the levels of TNF-α, MDA, NO and ONOO- in the lung tissues were increased significantly. In emodin treatment groups, the pulmonary indexes were lower than that in model group. The pathological injury of the lung tissues was alleviated. The levels of TNF-α, MDA, NO and ONOO- in the lung tissues were decreased. CONCLUSION:Emodin has a protective effect on lung injury induced by hepatic fibrosis in rats.     

Effect of salidroside on alcohol-injuced hepatic injury in rats

AIM:To investigate the effect of salidroside on alcoholic hepatic injury in rats. METHODS:The SD rats were randomly divided into 5 groups:negative control group, model group, bifendate group, and low-and high-dose salidroside groups. The rats in model group were administered with 56% alcohol, while the rats in negative control group was administered with saline. The rats in bifendate group and salidroside groups were administered with corresponding drugs every day. The blood and the liver tissues were collected to measure triacylglycerol (TG), alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA) and superoxide dismutase (SOD). The pathological changes of the liver tissues were observed with HE staining. Tumor necrosis factor-α (TNF-α) and nuclear factor-κB (NF-κB) were measured by ELISA and the protein and mRNA expression levels of TNF-α and NF-κB were detected by Western blot and RT-PCR. RESULTS:Compared with model group, the levels of TG, ALT, AST, MDA, TNF-α and NF-κB were reduced, while the activity of SOD was enhanced in salidroside group (P<0.05). The liver tissue injury was significantly attenuated. CONCLUSION:Salidroside improves the pathological changes, reduces inflammation, increases the activity of antioxidant enzymes and reduces lipid peroxidation in the liver with alcohol-induced injury. This effect may be related to regulating the NF-κB-mediated inflammatory responses.     

Morphology of endoplasmic reticulum and expression of GRP78 in rat fibrotic liver

AIM: To observe the changes of endoplasmic reticulum and the biomarker of endoplasmic retidum stress (ERS), glucose-regulated protein 78(GRP78),in the process of liver fibrosis induced by carbon tetrachloride (CCl₄). METHODS: Male Wistar rats weighing 180 g to 220 g were divided into control group and liver fibrosis group. The rats in liver fibrosis group were induced by hypodermic injection of CCl₄ for 4 weeks or 8 weeks. The liver index and the serumactivity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were analyzed. The liver fibrosis and the morphological changes of endoplasmic reticulum were observed under light and electronic microscopes, respectively. Additionally, the expression of GRP78 at mRNA and protein levels was determined by real-time PCR and the method of immunohistochemistry, respectively. RESULTS: The liver index, serum ALT and AST activity in liver fibrosis group were obviously higher than those in control group. Swelling and reduced number of endoplasmic reticulum were observed in the hepatocytes of fibrotic rats compare to the controls. The levels of GRP78 protein and GRP78 mRNA in the liver of hepatic fibrotic rats were obviously higher than those in the control rats. CONCLUSION: In the process of liver fibrosis induced by CCl₄, the obvious morphological changes of endoplasmic reticulum and increased expression of ERS protein indicate that ERS plays an important role in the liver fibrosis.     

Effects of glycine on insulin resistance and cognitive impairment induced by high-fructose diet

AIM: To investigate the role of intestinal endotoxemia (IETM) in insulin resistance (IR) and cognitive impairment, and to explore the protective mechanisms of glycine in rats with high-fructose diet. METHODS: The rats in model group were fed with 8% fructose water, and the rats in intervention group were fed with water containing 8% fructose and 1% glycine. The body weight and systolic pressure were measured monthly. After 8 months, plasma glucose, plasma lipids, glucose tolerance and plasma endotoxin (LPS) were detected. Plasma insulin, pro-inflammatory cytokines in plasma and cerebral cortex were determined by ELISA, and HOMA-IR was also calculated. The molecules of insulin signaling pathway in cerebral cortex were determined by Western blotting. The cognitive functions of the rats were tested by Morris water maze. RESULTS: The weight gain in model group was increased from the 3rd month to the 6th month, and systolic pressure was increased after the 3rd month as compared with control group. Glycine significantly reduced the weight gain in the 4th month and the 6th month, and significantly reduced the systolic pressure from the 4th month to the 6th month. Meanwhile, glycine partly attenuated dyslipidemia and glucose intolerance, and lowered the levels of plasma LPS, plasma insulin, HOMA-IR and pro-inflammatory cytokines in plasma and cortex. Furthermore, glycine attenuated the abnormal expression of insulin signaling proteins and cognitive impairment. CONCLUSION: Long-term fructose diet induces the rats to peripheral and neuronal IR, which accompanies IETM and low-grade inflammation. Glycine attenuates IR and cognitive impairment by lowering IETM.     

Anti-aging Klotho protein reduce the hypoxia/reoxygenation injury of neonatal rat myocardial cells

AIM: To study the effects of anti-aging Klotho protein on neonatal rat myocardial cells with hypo-xia/reoxygenation (H/R) injury. METHODS: The cardiomyocytes of neonatal SD rats were cultured to establish hypoxia/reoxygenation model. The myocardial cells were divided into normal control group, H/R model group, different concentrations of Klotho protein (0.1 μmol/L, 1 μmol/L and 10 μmol/L) pretreatment groups. The myocardial cells pulse frequency was observed before and after H/R. The cell viability was measured by MTT assay. The leakages of LDH, CK and AST, the content of MDA and the activity of SOD were detected. The apoptotic rate of the myocardial cells was analyzed by flow cytometry. The mRNA expression of endoplasmic reticulum stress markers and apoptosis-related molecules GRP78, CRT, CHOP and caspase-12 was measured by real-time PCR. The protein levels of CHOP, caspase-12 and phosphorylated Akt in the myocardial cells were determined by Western blot. RESULTS: Compared with normal control group, the pulse frequency, cell viability rate and SOD activity of myocardial cells were significantly decreased, the cell apoptotic rate as well as the contents of LDH, CK, AST and MDA were increased in H/R model group. The mRNA expressions of GRP78, CRT, CHOP and caspase-12 as well as the protein levels of CHOP and caspase-12 were increased, whereas p-Akt level was decreased obviously. Compared with H/R model group, the pulse frequency, cell viability rate and SOD activity were increased significantly, the cell apoptotic rate as well as the contents of LDH, CK, AST and MDA were decreased in Klotho pretreated group. The mRNA expression of GRP78, CRT, CHOP and caspase-12 as well as the protein levels of CHOP and caspase-12 were decreased, while p-Akt level increased significantly. CONCLUSION: Anti-aging Klotho protein improves the myocardial cell survival and inhibits the apoptosis by increasing the resistance of the cells to oxidative stress and excessive endoplasmic reticulum stress response, which is related with the activation of Akt phosphorylation in H/R-injured mycardial cells.     

Protective effect of curcumin on ERS-induced NASH rat hepatocytes

AIM: To investigate whether curcumin reduces hepatocyte apoptosis in the rats with non-alcoholic steatohepatitis (NASH) by inhibiting endoplasmic reticulum stress (ERS) and thus exerting a protective effect on the liver. METHODS: Male SD rats (n=30) were randomly divided into normal control group (n=10), model group (n=10) and curcumin group (n=10). NASH model was established by feeding the rats with high-fat diet for 4 weeks. The rats in curcumin group was given curcumin (200 mg/kg) daily by gavage, while the rats in model group and normal control group were given the same volume of saline. Four weeks later, the rats were killed, and their blood and liver tissues were collected. The serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected, liver histopathological changes were observed by HE staining, the expression of glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) was determined by Western blot, and apoptosis was detected by TUNEL method. RESULTS: Compared with normal control group, the levels of serum ALT and AST in model group were significantly increased, and the levels of serum ALT and AST in curcumin group were significantly lower than those in model group (P<0.05). At the same time, the steatosis and inflammation of hepatocytes in curcumin group were less than those in model group, and no obvious necrosis was observed. Compared with normal control group, the protein expression levels of GRP78 and CHOP in model group were increased, while the protein expression levels of GRP78 and CHOP in curcumin group were decreased compared with model group (P<0.01). TUNEL results showed that apoptotic hepatocytes in model group were significantly more than those in normal control group, while those in curcumin group were significantly fewer than those in model group. CONCLUSION: Hyperlipidemia induces excessive ERS in the hepatocytes, thus triggering apoptosis and leading to NASH. The mechanism of curcumin reducing hepatocyte apoptosis may be related to its inhibition of ERS.     

Effects of inhibition of Kupffer cell and splenectomy on thioacetamide-induced hepatic injury

AIM: To examine the effects of inhibition of Kupffer cell and splenectomy on intestinal endotoxemia and hepatic injury. METHODS: The hepatic injury model was established by treatment with thioacetamide (TAA). At the same time, inhibition of Kupffer cells by intravenous GdCl₃ and splenectomy were performed. Serum alanine aminotransferase (ALT), TNF-α, endotoxin content and phagocytic index were observed. RESULTS: In the TAA+GdCl₃ group, and TAA+splenectomy group, the endotoxin content was significently higher than that in normal and TAA group (P<0.05). The plasma TNF-α, ALT and total bilirubin were significantly lower than those in TAA group (P<0.05). CONCLUSION: Inhibition of Kupffer cells and splenectomy increase plasma endotoxin level, but decreases the plasma TNF-α levels and alleviates the hepatic injury induced by TAA.     

Protective effect of A. auricula-judae extracts on liver function in septic rats

AIM: To explore the effects of Auricularia (A.) auricula-judae extracts on the liver function in septic rats. METHODS: Forty male Wistar rats were randomly divided into control group, model group, A. auricula-judae polysaccharide group and A. auricula-judae crude extract group. Septic model was induced by the procedure of cecal ligation and puncture (CLP). Intragastric administration was performed every 8 h 3 days prior to CLP. The plasma levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), endotoxin(ET), tumor necrosis factor α(TNF-α), interleukin 6(IL-6) and IL-1β were detected 12 h after CLP. The specimens of the liver were collected to observe the pathological changes. The expression of NF-κB in the liver tissues was detected by the method of immunohistochemistry. RESULTS: Compared with the CLP rats, the intervention of A. auricula-judae polysaccharide and A. auricula-judae crude extract to the septic rats significantly decreased the serum levels of ALT, AST, ET, TNF-α, IL-1β and IL-6 (P<005). The pathological changes of the liver tissues in treatment groups were significantly attenuated compared with CLP group. CONCLUSION: A. auricula-judae polysaccharide and A. auricula-judae crude extract protect liver against sepsis-induced injury by inhibiting the systemic inflammatory response.     

Protective effect of Yiqi-Wenyang-Huoxue-Huatan formula on HHPH rat brain by suppressing excessive endoplasmic reticulum stress

AIM: To investigate whether Yiqi-Wenyang-Huoxue-Huatan formula (YWHHF) attenuats brain injury induced by hypoxia-hypercapnia pulmonary hypertension (HHPH) in the rats by inhibiting excessive endoplasmic reticulum stress response. METHODS: Healthy SPF male SD rats (n=50) were randomly divided into 5 groups: control group, hypoxia-hypercapnia group, low-dose YWHHF group, middle-dose YWHHF group and high-dose YWHHF group. The rats in control group lived in normal environment, while the rats in other 4 groups were raised for 4 weeks in oxygen tank with low oxygen concentration and high CO₂ concentration. YWHHF was perfused in the rats of low-, middle-and high-dose groups at 0.15, 0.3 and 0.6 g/kg daily, respectively. The rats in hypoxia-hypercapnia group were given isometric distilled water. The surgery was performed on the rats after 4 weeks, and the brain and lung tissues were quickly collected to detect brain water content and observe the morphological changes after mean pulmonary artery pressure recording and heart perfusion. The caspase-3 activity and the apoptotic index of the brain cells were determined. The expression of c-Jun N-terminal kinase (JNK), caspase-12, C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (GRP78) at protein and mRNA levels in brain tissues was detected by Western blot and RT-PCR. RESULTS: Compared with control group, mean pulmonary artery pressure, brain water content, brain apoptotic index, caspase-3 activity, and the protein and mRNA levels of JNK, caspase-12, CHOP and GRP78 in the rest 4 groups were increased, and the brain and lung tissues had obvious damage under light microscope. Compared with hypoxia-hypercapnia group, mean pulmonary artery pressure, brain water content, brain apoptotic index, caspase-3 activity, and the protein and mRNA expression of JNK, caspase-12, CHOP and GRP78 in low-, middle-and high-dose YWHHF groups were decreased, and the pathological damage of the brain and lung tissues was obviously reduced under light microscope. These changes in middle-dose YWHHF group were the most significant. CONCLUSION: YWHHF effectively relieves the brain injury induced by HHPH in rats, which may be associated with inhibiting excessive endoplasmic reticulum stress response.     

Effect of azithromycin on airway inflammation and airway mucus hypersecretion in rats with chronic obstructive pulmonary disease

AIM: To observe the effect of azithromycin on the rats with chronic obstructive pulmonary disease (COPD), and to explore the underlying mechanism about the airway inflammation and mucus hypersecretion. METHODS: Male SD rats were randomly divided into normal control group, COPD model group, azithromycin treatment group. The COPD model was established by the method of cigarette smoking combined with intratracheal injection of LPS. Pathological changes of the bronchi and lung tissues of the rats were observed with HE staining. Pulmonary ventilation function in the rats was detected with pulmonary function instrument. The levels of IL-8, IL-17 and TNF-α in bronchoalveolar lavage fluid (BALF) were measured by ELISA. The expression of MUC5ac and TLR4 at mRNA and protein levels in bronchi and lung tissues was determined by real-time PCR and Western blot.RESULTS: HE staining showed that the changes of bronchi and lung tissues in model group were consistent with typical pathological manifestations of COPD. Compared with model group, these changes were alleviated in treatment group. The pulmonary functions in model group were significantly decreased compared with control group. The levels of IL-8, IL-17 and TNF-α in the BALF in model group were significantly increased compared with control group (P <0.05). The expression of MUC5ac and TLR4 at mRNA and protein levels in model group was significantly higher than that in control group (P <0.05). Compared with model group, the degree of the descent in pulmonary function in treatment group was significantly lessened. Compared with model group, the levels of IL-8, IL-17 and TNF-α in treatment group were significantly inhibited (P <0.05). Furthermore, the expression of MUC5ac and TLR4 at mRNA and protein levels in treatment group was significantly lower than that in model group (P <0.05). CONCLUSION: Azithromycin decreases the levels of IL-8, IL-17 and TNF-α in the BALF of COPD model rats, inhibits the protein expression of MUC5ac and TLR4 in the lung tissues, thus playing a preventive and therapeutic role to reduce airway inflammation and airway mucus hypersecretion.     

Inhibitory effect of salidroside on liver oxidative stress in rats with non-alcoholic steatohepatitis

AIM：To explore the effects of salidroside (SDS) on the oxidative stress in liver tissues from rats with non-alcoholic steatohepatitis (NASH). METHODS：The experimental animal model of NASH was established in SD rats fed on high-fat and high-cholesterol diet (HFHCD) for 14 weeks. SDS (300 mg·kg-1·d-1) was administered via gavage daily from the 8th week after HFHCD feeding. At the end of the 14th week, serum samples were taken for detection of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG) and total cholesterol (TC). Liver tissues were taken for TG, TC, malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) detection. The content of 8-isoprostaglandin F2α (8-iso-PGF2α) in liver tissues was determined by ELISA. The liver histopathological changes were observed under microscope with HE staining. The expression of 8-hydroxydeoxyguanosine (8-OHdG) in liver tissues was determined by immunohistochemical staining. RESULTS：At the end of the 14th week, ALT, AST, TG and TC in serum, and TG, TC, MDA and 8-iso-PGF2α in liver homogenate in NASH model group were significantly increased compared with control group, while SOD and GSH in liver tissues were significantly decreased. The liver expression of 8-OHdG in NASH model group was higher than that in control group. Compared with NASH model group, SDS significantly inhibited the elevation of serum ALT, AST, TG and TC, and liver TG, TC, MDA and 8-iso-PGF2α, but increased the levels of SOD and GSH in liver tissues. Meanwhile, the liver histopathological score and 8-OHdG expression were decreased in SDS treatment group. CONCLUSION：Salidroside can effectively inhibit steatohepatitis induced by HFHCD, and its antioxidant effect may be one of the mechanisms.     

Effect of oleanolic acid on expression of TNF-α and collagen in silicotic rats in vivo

AIM: To observe the effect of oleanolic acid (OA) on the expression of Tumor necrosis factor-α (TNF-α) and collagen in silicotic rats in vivo and its possible mechanism. METHODS: Male Wistar rats were divided into 4 groups according to the randomized block design: control group, model group, OA group and solvent control group (20 rats in each group). Except control group, the rats in other groups were induced by intratracheal instillation of silicon di-oxide (SiO₂; 250 mg/kg). The rats in OA group were intragastrically administered with OA (60 mg/kg) from the second day of giving SiO₂. The rats in solvent control group were gavaged daily with 0.6% sodium carboxymethyl cellulose solution (10 mL/kg). The rats in control group were given normal saline under the same condition for 56 consecutive days. All rats were killed at the 7th, 14th, 28th and 56th days. The lung coefficient was detected and the morphological changes were observed. The serum contents of TNF-α were detected by ELISA. The content of total collagen in the lung tissue was measured. The protein level of nuclear factor-κB (NF-κB) in the lung tissue was determined by immunohistochemical method. RESULTS: (1) According to the morphological changes, the silicosis model was successfully established. Compared with control group, the lung coefficient and total collagen increased obviously in model group and solvent control group. The lung coefficient and total collagen content in OA group at each time point reduced compared with those in model group and solvent group, and increased compared with those in control group at the corresponding time points. (2) The serum contents of TNF-α in model group and solvent control group significantly increased, peaking at the 14th day, slightly decreasing afterward, and showing statistically significant difference at each time point compared with those in control group. No significant difference between model group and solvent group at different time points was observed. OA had inhibitory effect on the contents of TNF-α compared with model group and solvent group at the corresponding time points. (3) NF-κB in model group and solvent control group significantly increased, peaking at the 28th day, and showing statistically significant difference at each time point compared with those in control group. The NF-κB expression in OA group was similar to model group, but significantly decreased compared with control group at each time point. CONCLUSION: OA inhibits the expression of TNF-α and collagen and attenuates the silicosis fibrosis, which may be related to the NF-κB pathway.     

PI3K/Akt regulates endoplasmic reticulum stress-mediated GRP78 induction

AIM: To investigate the effect of PI3K/Akt pathway on endoplasmic reticulum (ER) stress-mediated glucose-regulated protein 78 (GRP78) induction in human embryonic kidney 293 cells (HEK293) cells.METHODS: PI3K inhibitor LY294002, dominant negative kinase-dead mutant vector for HA-Akt (K179M) and Akt1 siRNAs were used to block the PI3K/Akt pathway under ER stress. Constitutively active expression vectors for Akt (myr-HA-Akt) were used to up-regulate Akt activity under ER stress. The effects of PI3K/Akt on ER stress-mediated GRP78 induction in HEK293 cells were determined by Western blotting and RT-PCR. RESULTS: GRP78 induction was inhibited by LY294002, Akt1 (K179M) and Akt1 siRNA, but was increased by myr-Akt1 in dithiothreitol-and thapsigargin-treated HEK293 cells. However, both myr-Akt2/3 and Akt2/3 siRNA had no effect on GRP78 induction in HEK293 cells under ER stress. Furthermore, the PI3K/Akt pathway didnt regulated GRP78mRNA induction but increased GRP78 protein stability.CONCLUSION: PI3K/Akt promotes GRP78 accumulation through increasing the stability of GRP78 protein in HEK293 cells under ER stress.     

Protective effects of taurine on LPS-induced myocardial damage in rats

AIM: To investigate the effects of taurine on lipopolysaccharide (LPS)-induced myocardial damage in rats. METHODS: Healthy male SD rats (n=30) were randomly divided into control group (CON), LPS model group (LPS) and taurine treatment group (TAU). The rats in CON group and LPS group were intravenously injected with normal saline, and the rats in TAU group were injected with taurine (100 mg/kg). After 2 h, the rats in LPS group and TAU group were intraperitoneally injected with LPS at 10 mg/kg, and the rats in CON group were injected with normal saline. Six hours after injection of LPS, the blood samples were collected for determination of superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) levels. The myocardial tissues were processed for histological examination and the analysis of Western blot. RESULTS: Compared with CON group, LPS significantly reduced SOD activity in the serum and heme oxygenase 1 (HO-1) protein expression in the myocardial tissues, increased the serum content of MDA and levels of TNF-α and IL-6. LPS also significantly elevated the levels of TNF-α and IL-6, and up-regulated the cyclooxygenase-2 (COX-2) expression and phosphorylation of nuclear factor kappa B (NF-κB) in the myocardial tissues. Taurine pretreatment significantly elevated SOD activity and HO-1 protein expression level, decreased the levels of COX-2, TNF-α, IL-6 and phosphorylated NF-κB. Histological observation showed that taurine reduced inflammatory response in the myocardial tissue. CONCLUSION: Taurine attenuates LPS-induced myocardial damage in rats. The beneficial effects of taurine may be associated with its reduction of p-NF-κB/COX-2 signaling by activation of HO-1/CO.