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.     

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.     

Effects of bisoprolol plus peridopril on myocardial endoplasmic reticulum stress in rats with doxorubicin-induced heart failure

ATM: To investigate the effects of bisoprolol (Bis) plus peridopril (Per) on myocardial endoplasmic reticulum stress (ERS) in rats with heart failure.METHODS: Male SD rats were randomly divided into normal control group, sham group, doxorubicin (DOX) group, bisoprolol treatment group (DOX+Bis group), peridopril treatment group (DOX+Per group) and bisoprolol plus peridopril treatment group (DOX+Bis+Per group). A rat model of heart failure was induced by intraperitoneal injection of DOX. Distilled water, bisoprolol, peridopril, and bisoprolol plus peridopril were administrated by gastric gavage for 35 d, respectively. The indexes of cardiac functions and plasma levels of brain natriuretic peptide (BNP) were measured, myocardial apoptosis was analyzed by TUNEL assay and myocardial protein expression of GRP78, CHOP, JNK, caspase-12 and SERCA2a was detected by Western blot.RESULTS: Compared with normal control group and sham group, cardiac output (CO), left ventricular fractional shortening (FS), and left ventricular ejection fraction (EF) of the rats in DOX group decreased significantly (P<0.01), the cardiomyocyte apoptotic index increased significantly (P<0.01), the myocardial protein levels of SERCA2a decreased significantly, and GRP78, CHOP, JNK and caspase-12 increased significantly (P<0.01). Compared with DOX group, CO, FS and EF of the rats in DOX+Bis group, DOX+Per group and DOX+Bis+Per group increased significantly (P<0.01), cardiomyocytes apoptotic indexes in DOX+Bis group, DOX+Per group and DOX+Bis+Per group decreased significantly (P<0.01), myocardial protein levels of SERCA2a in DOX+Bis group, DOX+Per group and DOX+Bis+Per group increased significantly, while GRP78, CHOP, SERCA2a, JNK and caspase-12 decreased significantly (P<0.05). Indicators except JNK in DOX+Bis+Per group were changed more significantly than those in DOX+Bis group or DOX+Per group (P<0.05).CONCLUSION: Bisoprolol plus peridopril therapy improves cardiac functions in a rat model of doxorubicin-induced heart failure with more significant effectiveness than using bisoprolol or peridopril alone, which may be related to inhibition of myocardial ERS and apoptosis.     

苹果miR396家族鉴定及在不定根发育过程中的表达分析

分析了苹果miR396家族进化特性及其在苹果不定根发育过程中的表达模式。结果表明：苹果miR396家族有4条成熟体和7条前体序列（pre-miRNA）。Mfold预测显示Pre-miR396家族7个成员序列均可形成典型稳定的茎环二级结构,最小折叠自由能介于–62.9 kal ? mol-1（pre-miR396b）~–51.9 kal ? mol-1（pre-miR396g）之间。系统发育进化树分析显示,pre-miR396家族亲缘关系可分为3个亚组（G1、G2、G3）,每个亚组内基因数量不同,分别含有11、9、19个。靶基因预测显示,苹果miR396靶基因包括MdGRF1、MdGRF2和MdGRF5等,降解组测序进一步验证了miR396对其候选靶基因MdGRF1、MdGRF2和MdGRF5的剪切关系。苹果miR396家族成员在侧根和果实中的表达量显著高于其他组织,其候选靶基因表达量则在花芽和腋芽中显著高于其他组织;不定根发育过程中,miR396家族不同成员表达模式存在显著差异,整体上呈上调表达趋势,其候选靶基因呈下调表达趋势;外源IBA处理显著诱导miR396家族成员的表达,尤其是在不定根诱导期和根系生长期更为显著。     

Effect of acteoside on behavioral changes and endoplasmic reticulum stress in prefrontal cortex of depressive rats

AIM: To explore the effect of acteoside on behavioral changes and endoplasmic reticulum stress (ERS) in prefrontal cortex of depressive rats. METHODS: Sprague-Dawley (SD) rats (n=108) were randomly divided into 6 groups:control group, model group, fluoxetine (20 mg/kg) group, low-dose (30 mg/kg) acteoside group, medium-dose (60 mg/kg) acteoside group and high-dose (120 mg/kg) acteoside group, with 18 rats in each group. The depressive-like rat model was established by chronic unpredictable mild stress (CUMS) combined with solitary way for 28 d. The rats in fluoxetine group and acteoside groups were treated with fluoxetine (20 mg/kg) or acteoside (30 mg/kg, 60 mg/kg and 120 mg/kg) once daily by intragastric administration for 3 weeks. The rats in control group and model group were both given equal volume of saline by intragastric administration for 3 weeks. The behavioral changes were detected by the open-field test and sugar preference experiment. The protein expression of glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) was assessed by immunofluorescence and Western blot. The caspase-3 activity was measured by spectrophotometer. RESULTS: Compared with control group, the total distance, time spent in the center and sugar intake were all decreased, the expression of GRP78 and CHOP was increased, and the activity of caspase-3 was increased in model group, fluoxetine group and acteoside groups (P<0.05). Compared with model group, the total distance, time spent in the center and sugar intake were increased, the expression of GRP78 and CHOP was reduced, and the activity of caspase-3 was decreased (P<0.05) in fluoxetine group and acteoside groups. CONCLUSION: Acteoside improves depressive-like behaviors in depressive rats, which may be related to the inhibition of ERS and neuronal apoptosis in prefrontal cortex.     

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.     

Protective effect of morinda officinalis oligosaccharides monomer HexB on hypoxia/reoxygenation-induced injury in HUVECs

AIM:To explore the protective effect of morinda officinalis oligosaccharides monomer HexB on hypoxia/reoxygenation (H/R)-induced injury in human umbilical vein endothelia cells (HUVECs). METHODS:HUVECs were treated with HexB, 4-phenylbutyric acid (4-PBA) and thapsigargin (TG), respectively. The cells were divided into control group, HexB group, H/R group, HexB+H/R group, 4-PBA+H/R group, TG group and HexB+TG group. The cell viability was measured by CCK-8 assay. The apoptotic rate was detected by flow cytometry. Western blot was used to determine the protein levels of endoplasmic reticulum stress (ERS) related molecules chaperone protein glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), apoptosis-related protein caspase-12 and phosphorylated c-Jun NH₂-terminal kinase (p-JNK). RESULTS:The viability of HUVECs was reduced in H/R group and TG group (P<0.05), increased in HexB+H/R, 4-PBA+H/R and HexB+TG group (P<0.05). The apoptotic rate, the protein levels of GRP78, CHOP, caspase-12 and p-JNK were increased in H/R group and TG group (P<0.05), weakened in the HexB+H/R group (P<0.05), 4-PBA+H/R group and HexB+TG group (P<0.05). No significant change in the apoptotic rate, cell viability, protein levels of GRP78, CHOP, caspase-12, p-JNK between HexB+H/R group and 4-PBA+H/R group was observed. CONCLUSION:HexB attenuates HUVECs injury caused by H/R through suppressing ERS and apoptosis. The possible mechanism may be involved in the apoptotic pathways related to GRP78, CHOP, caspase-12 and p-JNK.     

Effects of AT1 receptor autoantibody on renal cell apoptosis and JNK expression in diabetic nephropathy rats

AIM:To study the effects of angiotensin Ⅱ type 1 receptor autoantibody (AT1-AA) on the apoptosis of renal cell and the expression of c-Jun N-terminal kinase (JNK) in diabetic nephropathy (DN) rats. METHODS:High-sucrose and high-fat diet and intraperitoneal injection of streptozotocin were utilized to induce DN rat model. We employed enzyme-linked immunosorbent assay (ELISA) for serum AT1-AA and TUNEL staining for renal cell apoptosis. Furthermore, Western blotting was performed to measure the levels of endoplasmic reticulum stress (ERS) chaperone glucose-regulated protein 78 (GRP78) and ERS-associated apoptosis protein p-JNK. RESULTS:The renal cell apoptotic rate in DN group was significantly increased compared with NC group, and the apoptotic renal cells in AT1-AA positive DN rats were much greater than those in AT1-AA negative DN rats (P<0.05). The protein levels of GRP78 and p-JNK were significantly increased compared with NC group. GRP78 and p-JNK protein levels also significantly increased in AT1-AA positive DN rats compared with AT1-AA negative DN rats. CONCLUSION: AT1-AA activates ERS response and induces renal cell apoptosis via the JNK apoptotic pathway in the renal tissues of DN rats.     

Prostaglandin E1 protects heart after myocardial infarction by inhibiting endoplasmic reticulum stress in rats

AIM To investigate the effect of prostaglandin E1 (PGE1) on heart after myocardial infarction (MI) in rats and its related molecular mechanism. METHODS Fifty male SD rats were divided into sham group, model group and model+PGE1 group. The MI rat model was established by ligation of left anterior descending coronary artery. Cardiac function in the rats was detected by echocardiogaphy. The myocardial histomorphologic changes were evaluated by HE and Masson staining. The MI area was measured by TTC staining. The cardiomyocyte death was detected by TUNEL staining. The protein levels of endoplasmic reticulum stress (ERS)-related factors glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP) and caspase-12, and apoptosis-related factors Bcl-2, Bax and cleaved caspase-3 were determined by immunofluorescence staining and Western blot. RESULTS Compared with sham group, the cardiac function in model group was decreased, with significant myocardial pathological changes. The MI area was enlarged, and the death of cardiomyocytes was promoted. The protein levels of GRP78, CHOP, caspase-12, Bax and cleaved caspase-3 in the myocardial tissues were significantly increased, while Bcl-2 was decreased (P<0.01). Compared with model group, the cardiac function in model+PGE1 group was significantly improved, and the myocardial pathological damage was significantlty attenuated. The MI area and myocardial cell death were significantly reduced. The protein levels of GRP78, CHOP, caspase-12, Bax and cleaved caspase-3 in the myocardial tissues were significantly decreased, while Bcl-2 was increased (P<0.01). CONCLUSION PGE1 reduces collagen deposition and inflammation, and improves cardiac function by reducing ERS level, thus protecting cardiomyocytes from MI damage.     

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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、新技术新品种以及园艺研究动态与信息等,适合园艺科研人员、大专院校师生及农业技术推广部门专业技术人员阅读参考。《园艺学报》是中文核心期刊,被英国《CAB文摘数据库》、美国CA化学文摘、日本CBST科学技术文献速     

Effect of hyperlipidemia and influence of simvastatin on endoplasmic reticulum stress in rat kidney

AIM: To investigate the role of endoplasmic reticulum stress in renal injury caused by hyperlipidemia and the influence effect of simvastatin. METHODS: Thirty male Wistar rats were randomly divided into three groups: rats in control group (n=10) were fed with normal diet; rats in high fat group (n=10) were fed with high fat diet; animals in simvastatin+high fat group (n=10) were fed with high fat diet and were received simvastatin 10 mg·kg-1·d-1 by gastric irrigation. After 18 weeks, the quantitative urine protein in 24 h, the serum cholesterol and triglycerides levels were tested. The pathological changes of renal tissue were observed under optic microscope. The expressions of GRP78 and p-JNK in renal tissues were examined by immunohistochemistry. The apoptotic cells in the kidney were detected by TUNEL staining. The mRNA expressions of GRP78 and CHOP were examined by RT-PCR. RESULTS: The quantitative urine protein in 24 h, the serum lipid, the expressions of GRP78 and p-JNK proteins, the mRNA expressions of GRP78 and CHOP as well as the apoptotic cells in renal tissues were increased in high fat group (P<0.01).The quantitative urine protein in 24 h, the serum lipid, the expression of GRP78 and p-JNK proteins, the mRNA expressions of GRP78 and CHOP as well as the apoptotic cells in renal tissues were remarkably reduced in simvastatin+high fat group than those in high fat group (P<0.05). CONCLUSION: The endoplasmic reticulum stress is engaged in the renal injury caused by hyperlipidemia. The simvastatin play a role in renal protection by inhibiting the endoplasmic reticulum stress in the kidney.     

Role of 78 kD glucose-regulated protein in development of hepatopulmonary syndrome induced by multiple pathogenic factors

AIM: To explore the role of 78 kD glucose-regulated protein (GRP78) in the development of hepatopulmonary syndrome (HPS) in rats and the relation to intestinal endotoxemia (IETM). METHODS: The experimental animals were randomly divided into HPS groups of the 4th week, the 6th week and the 8th week. Normal control groups at the corresponding time points were also set up. The Wistar 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 tap water. Histopathological changes of the lung and liver were observed under microscope with the staining of hematoxylin and eosin (HE). The concentrations of alanine amino transferase (ALT), endotoxin and tumor necrosis factor α (TNF-α) in plasma, the contents of TNF-α and malondialdehyde (MDA) in the lung tissues were detected. The expression of GRP78 at mRNA and protein levels in the lungs was measured by the methods of RT-PCR and Western blotting, respectively. RESULTS: The level of endotoxin in plasma was gradually increased with the HPS development. The expression of GRP78 at mRNA and protein levels was also gradually increased with the HPS development and was significant at every time point. The endotoxin in plasma was positively correlated with the expression of GRP78 protein in the lung tissues of the rats with HPS. With the HPS development, the levels of ALT and TNF-α in plasma and the contents of TNF-α and MDA in the lung tissues were gradually increased. The content of endotoxin in plasma and the protein expression of GRP78 in the lung tissues were positively correlated with the contents of TNF-α in plasma and TNF-α and MDA in the lung tissues. The contents of TNF-α in plasma and GRP78 at mRNA and protein levels and TNF-α in the lung tissues were higher in the rats with HPS at every time point than those in normal control group. At the 6th week and the 8th week, the contents of endotoxin and ALT in plasma and MDA in the lung tissues of the rats with HPS were significantly higher than those in normal control group. CONCLUSION: IETM originated from the liver cirrhosis acts as a critical stressor of endoplasmic reticulum (ER) stress and activates ER stress in the lung by oxidative stress, resulting in increased expression of GRP78. Therefore,the increased expression of GRP78 induced by ER stress may play an important role in the development of HPS in rats.     

Protective effect of Huangqi injection combined with puerarin injection on myocardium of type 2 diabetes mice

AIM:To investigate the effect of Huangqi injection combined with puerarin injection on the myocardium of the mice with type 2 diabetes. METHODS:Diabetic KKAy mice were randomly divided into model group and treatment group (Huangqi injection combined with puerarin injection). The male KKAy mice of the same age were used as control group. All mice were sacrificed at 21, 24 and 28 weeks. Morphological changes of the myocardium were observed by HE staining. Apoptosis of the cardiomyocytes was measured by TUNEL staining. The mRNA levels of glucose-regulated protein 78(GRP78), C/EBP hoinologous protein (CHOP) and p53 up-regulated modulator of apoptosis (PUMA) were detected by real-time PCR, and the protein levels of GRP78, CHOP, PUMA, caspase-3, cleaved caspase-3, caspase-9, cleaved caspase-9, poly(ADP-ribose) polymerase (PARP) and cleaved PARP were determined by Western blot. RESULTS:Cardiomyocyte hypertrophy, partly dissolved sarcoplasm and necrosis were observed in model group, and these lesion were alleviated in treatment group. Obvious increased apoptosis in model group and significantly decreased apoptosis of cardiomyocytes in treatment group was observed (P<0.05). At 21, 24 and 28 weeks, the mRNA and protein levels of GRP78, CHOP and PUMA and the protein levels of cleaved caspase-3, cleaved caspase-9 and cleaved PARP in model group were increased significantly as compared with control group (P<0.01), and these in treated group were decreased compared with model group. CONCLUSION:Huangqi injection combined with puerarin injection has cardioprotective effects on type 2 diabetes mice and its mechanism of the action was implemented via inhibiting the activation of endoplasmic reticulum stress and caspase pathway, thus resulting in suppressed apoptosis.     

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.     

PQS attenuates cardiomyocyte apoptosis induced by thapsigargin through inhibiting endoplasmic reticulum stress

AIM:To study the effect of Panax quinquefoliumsaponin (PQS) on cardiomyocyte apoptosis induced by thapsigargin (TG). METHODS:Primary cultured cardiomyocytes from neonatal SD rats were divided into control group, TG group, PQS (40 mg/L, 80 mg/L and 160 mg/L)+TG group, si-PERK+TG group, and mock+TG group. The cells were treated with 1 μmol/L TG for 24 h to induce apoptosis. The PERKgene in the cardiomyocytes was knocked down by RNAi. The cell viability was detected by CCK-8 assay. Apoptosis was analyzed by flow cytometry. Wes-tern blotting was used to determine the expression of ERS molecules GRP78, CRT, ATF4 and CHOP, anti-apoptosis protein Bcl-2 and pro-apoptosis protein Bax. RESULTS:Compared with control group, TG significantly and the apoptosis, reduced the cell viability (P<0.05), increased the phosphorylation of PERK and eIF2α, increased the expression of GRP78, CRT, ATF4, CHOP and pro-apoptosis protein Bax, and decreased the expression of anti-apoptosis protein Bcl-2 (P<0.05). Compared with TG group, PQS treatment (160 mg/L) significantly reduced the apoptosis and increased the cell viability (P<0.05). All the 3 different concentrations of PQS significantly increased the expression of anti-apoptosis protein Bcl-2 and reduced the expression of pro-apoptosis protein Bax (P<0.05) in a dose-dependent manner. PQS pretreatment and knockdown of PERK both reduced the protein levels of GRP78, CRT, PERK, p-PERK, eIF2α, p-eIF2α, ATF4, CHOP and pro-apoptosis protein Bax, and increased the expression of anti-apoptosis protein Bcl-2 (P<0.05). CONCLUSION: PQS at concentration of 160 mg/L attenuated cardiomyocyte apoptosis induced by TG. PQS had the similar effect as PERKknockdown on cardiomyocyte apoptosis. The mechanism may be associated with inhibiting PERK-eIF2α-ATF4-CHOP pathway of ERS-related apoptosis.     

Protective effects of somatostatin and octreotide on hepatocytes

AIM: To investigate the protective effect of somatostatin (SST) and octreotide (OCT) on rat hepatocytes. METHODS: The primary hepatocytes were pretreated with different concentrations of SST and OCT. The levels of alanine minotransferase (ALT) and aspartate aminotransferase (AST) in culture supernatant were analyzed by the model of ethanol/carbon tetrachloride (CCl4)-induced hepatocyte injury. Additionally, 75 Sprague-Dawley rats were divided into 5 groups at random, including normal control, model control, SST-treated model groups at high, medium and low doses (200 μg·kg-1·d-1, 100 μg·kg-1·d-1 and 50 μg·kg-1·d-1, respectively). Except for the normal controls, all rats were injected with 40% CCl4 subcutaneously for 8 weeks to establish hepatic fibrosis. Meanwhile, rats of SST-treated model groups were given at different doses of SST twice a day in the same way. Thereafter, the liver function and apoptosis index of hepatocytes were detected by standard enzyme method, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), respectively. RESULTS: Compared with those of injury model group, the hepatocytes pretreated with SST (10-8-10-6 mol/L) and OCT (10-7-10-5 mol/L) exhibited significantly decreased levels of ALT and AST in the culture supernatant. Furthermore, most indices of liver function including ALT, AST, alkaline phosphatase (ALP), total bilirubin (TBIL) and albumin (ALB) improved obviously in all SST-treated groups, especially in the group treated with low dose of SST. The apoptosis index of hepatocytes in the fibrotic liver was also reduced greatly by the treatment with low dose of SST. CONCLUSION: SST and OCT may protect hepatocytes against CCl4-induced injury, inhibit hepatocyte apoptosis, and improve the liver function. These findings suggest them a potential efficiency in the prevention of hepatic fibrosis.     

Curcumin attenuates lung ischemia-reperfusion injury in mice through inhibiting JNK pathway and excessive endoplasmic reticulum stress

AIM: To investigate the role of curcumin (Cur) in attenuating lung ischemia-reperfusion (I/R) injury by inhibiting c-Jun N-terminal kinase(JNK) pathway and excessive endoplasmic reticulum stress (ERS) in mice. METHODS: Mouse model of lung I/R injury in situ was established in the left lung in vivo. Sixty mice were randomly divided into 6 groups (n=10 in each group), including sham group, I/R group, dimethyl sulfoxide solvent control group (I/R+DMSO group) and curcumin groups (I/R+ low, medium or high dose of Cur group). Left lung tissue was isolated after the experiment. The ratio of wet lung weight to dry lung weight (W/D), and total lung water content (TLW) were measured. The histological structure and ultrastructure of the left lung were observed under light and electron microscopes, and scored by alveolar damage index of quantitative assessment (IQA). The mRNA expression and protein levels of JNK and GRP78 were measured by RT-PCR and Western blotting. Apoptotic cells in the lung tissue were determined by TUNEL method. RESULTS: Compared with sham group, all indexes above in I/R group and DMSO group were significantly increased. No significant difference of all indexes between I/R group and DMSO group was observed. Compared with DMSO group, the indexes above in low, medium and high doses of Cur groups were decreased, especially in high dose of Cur group, but the expression level of GRP78 had no statistical difference. CONCLUSION: I/R induces excessive ERS in the lung tissue and results in lung injury. Cur has a protective effect on lung against I/R injury, which may be related to inhibition of apoptosis mediated by JNK pathway in ERS.     

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.     

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.