Effect of wogonoside on inflammatory response in mice with viral myocarditis induced by Coxsackie virus B3

AIM: To investigate the effect of wogonoside on the inflammatory response of mice with Coxsackie virus B3 (CVB3)-induced myocarditis and its possible regulatory mechanism. METHODS: A mouse model of viral myocarditis was constructed by infecting BALB/c mice with CVB3. BALB/c mice (n=40) were randomized into 4 groups: normal group, CVB3-induced viral myocarditis group, CVB3-induced viral myocarditis combined with wogonoside treatment group and CVB3-induced viral myocarditis combined with wogonoside plus AKT agonist treatment group. All the mice were sacrificed 7 days after treatment. In the first 3 groups, HE staining was applied to detect the infiltration of inflammatory cells in the myocardium, ELISA was applied to detect the serum levels of interleukin-1β (IL-1β) and IL-6, while Western blot was applied to detect the protein expression of inflammatory factors and the activation of AKT/NF-κB pathway. Inaddition, the activation of AKT/NF-κB pathway in the 4 groups was detected by Western blot analysis. RESULTS: HE staining showed that there was a large amount of inflammatory cell infiltration in the myocardium of CVB3-induced viral myocarditis mice, as compared with the normal group, which was significantly reduced by wogonoside treatment (P<0.05). The serum levels of IL-1β and IL-6 in the mice after CVB3 infection were significantly higher than those in normal group (P<0.05), which was also significantly reduced by wogonoside treatment (P<0.05). Western blot analysis indicated that wogonoside treatment significantly reduced the expression of inflammatory factors IL-1β and IL-6, and the phosphorylation of AKT/NF-κB pathway-related proteins in the myocardial tissue (P<0.05). After administration of AKT agonist, the inhibitory effect of wogonoside on NF-κB phosphorylation and inflammatory factors expression was significantly eliminated (P<0.05). CONCLUSION: Wogonoside attenuates the inflammatory response of mice with viral myocarditis by inhibiting the AKT/NF-κB pathway.     

LBP regulates PI3K/Akt/eNOS signaling pathways in ovariectomized rat myocardium to exert antioxidative effect

AIM: To observe the influence of Lycium barbarum polysaccharide (LBP) on the PI3K/Akt/eNOS signaling pathways in ovariectomized rat myocardium. METHODS: Female SD rats (n=30) were divided into sham operation group, ovariectomized group, progynova group, high-dose LBP group and low-dose LBP group. The serum levels of estradiol, lactate dehydrogenase (LDH) and creatine kinase (CK) were measured by ELISA. The myocardial contents of H₂S and oxidative stress injury-related indicators were also detected. The morphological changes of the myocardium were observed with HE staining. The expression of eNOS and PI3K/Akt pathway-related proteins in the myocardium was determined by Western blot. RESULTS: Compared with sham operation group, the serum level of estradiol, the content of H₂S, the activity of GSH-Px, and the expression of eNOS and PI3K/Akt pathway-related proteins in the myocardium in ovariectomized group were all decreased, and the levels of ROS and MDA in the myocardium were increased (P<0.05). The serum levels of LDH and CK were also increased. The arrangement of the myocardial cells was disordered, and the intercellular space was also increased in the ovariectomized group. Compared with ovariectomized group, the serum level of estradiol, the myocardial levels of H₂S and GSH-Px, and the protein levels of eNOS and phosphorylated Akt were all increased in high dose group, while the levels of ROS and MDA in the myocardium were decreased (P<0.05). The serum levels of LDH and CK were also decreased. The morphological changes of the rat myocardium were improved in high dose group. CONCLUSION: LBP prevents and treats postmenopausal cardiovascular lesions through regulating PI3K/Akt/eNOS signaling pathways in ovariectomized rats.     

Effects of simvastatin on expression of Bcl-2 and Bax in myocardium of rats with renal ischemia-reperfusion injury

AIM: To observe the effect of simvastatin on myocardial tissue after renal ischemia-reperfusion injury and its mechanism. METHODS: A rat model of renal ischemia-reperfusion injury was prepared by clamping the bilateral renal arteries for 45 min. The rats (n=36) were randomly divided into sham operation group, renal ischemia-reperfusion (I/R) group and simvastatin group with 12 rats in each group. The content of serum creatinine (SCr), blood urea nitrogen (BUN) and myocardial tissue malondialdehyde (MDA), the myocardial activity of lactate dehydrogenase (LDH), creatine kinase (CK) and superoxide dismutase (SOD), and the myocardial protein expression of Bcl-2 and Bax were detected. RESULTS: Compared with sham operation group, the content of SCr, BUN and myocardial MDA, and the myocardial activity of LDH and CK in I/R group were significantly increased (P<0.05), and the activity of SOD was significantly decreased (P<0.05). Compared with I/R group, the content of SCr, BUN and myocardial MDA, and the myocardial activity of LDH and CK in simvastatin group were significantly decreased (P<0.05), while SOD activity was enhanced (P<0.05). The protein expression of Bcl-2 and Bax in sham operation group was less than that in I/R group (P<0.05), and the protein level of Bax in simvastatin group was significantly lower than that in I/R group (P<0.05), while the protein level of Bcl-2 was increased (P<0.05). CONCLUSION: Simvastatin has a protective effect on the myocardium of the rats with renal ischemia-reperfusion injury, and the protective mechanism may be related to the elimination of free radicals by simvastatin, increase in the protein expression of Bcl-2 and decrease in the protein expression of Bax.     

Expression of MMP-2 and NF-κB in myocardium of mice with viral myocarditis

AIM: To observe the effects of TNF-α/nuclear factor-κB(NF-κB)/matrix metalloproteinase-2(MMP-2) pathway on the expression of MMP-2 in the mice with viral myocarditis. METHODS: Six-week-old inbred male mice were randomly assigned to control and myocarditis group. The mice in myocarditis group and control group were intraperitoneally inoculated with 0.1 mL 10^-5.69 TCID50/mL coxsackievirus B3 and vehicle (PBS), respectively. Ten mice were sacrificed at the 4th and 10th days after injection. The blood and heart specimens were harvested. The serum content of TNF-α was measured by ELISA. The myocardial levels of MMP-2, NF-κB p65 and IκBα were determined by Western blot. RESULTS: Compared with control group, the protein expression of MMP-2 and NF-κB p65 in the myocardium and the serum content of TNF-α were significantly increased in myocarditis group (P<0.05). The protein expression of IκBα was lower in myocarditis group than that in control group (P<0.05).CONCLUSION: TNF-α, NF-κB p65 and MMP-2 were higher in the mice with acute viral myocarditis. The increased expression of them might be involved in the pathogenesis of viral myocarditis.     

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.     

Ethanol extract from Cortex Albiziae attenuates mouse acute liver injury induced by carbon tetrachloride via modulation of NF-κB pathway

AIM:To investigate the protective effect of ethanol extract from Cortex Albiziae on acute liver injury, and to explore its possible mechanism. METHODS:Acute liver injury in mice was induced by single intraperitoneal injection of 25% carbon tetrachloride (olive oil solubilization). The effective parts of ethanol extract from Cortex Albizziae against acute liver injury were screened. The pathological changes of the liver tissues were examined by pathological sections with HE staining. The activity of total superoxide dismutase (T-SOD) and the content of malondialdehyde (MDA) of the liver tissues were detected, the serum levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were mea-sured by ELISA, and the protein expression levels of NF-κB p65, Bcl-2 and Bax in the liver cells of the mice in each group were determined by Western blot. RESULTS:Compared with model group, the serum levels of AST and ALT in low-dose n-butanol phase of ethanol extract from Cortex Albiziae (AB-L, 4 mg·kg^-1·d^-1) group and high-dose n-butanol phase of ethanol extract from Cortex Albiziae (AB-H, 8 mg·kg^-1·d^-1) group were significantly decreased. The necrosis extent and degree of the hepatocytes and infiltration of inflammatory cells were significantly lower than that in model group. Compared with model group, the serum levels of TNF-α and IL-6 in AB-H group and AB-L group were significantly decreased (P<0.05). The protein level of NF-κB p65 in the nuclei of mouse liver cells in AB-H group and AB-L group were also decreased significantly (P<0.05). Compared with model group, the protein expression of Bax was decreased, the protein expression of Bcl-2 was increased, and the Bcl-2/Bax ratio was increased in AB-L group and AB-H group. CONCLUSION:The n-butanol phase of ethanol extract from Cortex Albiziae may protect the liver by reducing the activation of NF-κB p65, inhibiting the excessive release of inflammatory cytokines IL-6 and TNF-α, and decreasing hepatocyte apoptosis via regulating Bcl-2 and Bax expression.     

Effect of metabolites of Clostridium butyricum,butyric acid and hydrogen,on acute gastric mucosal lesion

AIM: To observe the antiulcer effect of butyric acid and hydrogen, the main metabolites of Clostridium butyricum (C. butyricum), and to explore the underlying mechanism. METHODS: The mouse model of acute gastric mucosal lesion was prepared by gavage with ethanol. The mice were randomly divided into 4 groups: normal group, model group, butyric acid group and hydrogen group. The mice in butyric acid group and hydrogen group were given butyrate and hydrogen prior to model establishment, respectively. Macroscopic observation of the pathological changes in gastric tissues was performed to evaluate the effect of the 2 metabolites of C. butyricum. Meanwhile, the mRNA expression levels of inflammatory factors, such as IL-12, RAN1 and MCP-1, were determined by RT-qPCR. The expression levels of apoptosis-related proteins Bcl-2 and Bax were detected by immunohistochemical staining. RESULTS: The macroscopic observation found that butyrate, not hydrogen, protected gastric mucosa. HE staining also showed that butyrate significantly attenuated the pathological damage of the gastric mucosa induced by ethanol. Compared with model group, the mRNA levels of inflammatory factors IL-12, RAN1 and MCP-1 in butyrate group significantly decreased (P<0.01). In butyrate group, the protein level of Bax was obviously decreased compared with model group (P<0.01), while the protein level of Bcl-2 was significantly increased (P<0.01). CONCLUSION: The gastric mucosa protective metabolite of C. butyricum may be butyric acid, not hydrogen. Butyric acid protects the gastric mucosa against ethanol-induced lesion by inhibiting the inflammation and reducing the expression ratio of Bax/Bcl-2.     

Effects of ligustrazine ferulate on myocardial apoptosis and apoptosis-related protein expression in rats with myocardial ischemia-reperfusion injury

AIM:To observe the effects of ligustrazine ferulate on the apoptosis of myocardial cells in rats with myocardial ischemia-reperfusion injury, and to explore its possible mechanism. METHODS:Sixty male SD rats were randomly divided into five groups: sham-operation group, ischemia-reperfusion group, ligustrazine (4 mg/kg) group, low-dose (4 mg/kg) ligustrazine ferulate group and high-dose (8 mg/kg) ligustrazine ferulate group. The rat myocardial ischemia-reperfusion model was established by 30 min of myocardial ischemia followed by 120 min of reperfusion. Drugs were administered to the rats by jugular vein injection 10 min before reperfusion. After the reperfusion was finished, the biochemical indicators in serum and the histological indexes in myocardium were detected. RESULTS: Compared with ischemia-reperfusion group, ligustrazine ferulate lowered the serum levels of creatine kinase MB form, lactate dehydrogenase, cardiac troponin I and malondialdehyde, elevated the activity of total superoxide dismutase in serum and the expression of Bcl-2 protein in myocardium, decreased the expression of Bax protein and myocardial apoptotic index, and increased the Bcl-2/Bax ratio (all P<0.01). All the indicators in ligustrazine ferulate groups were dose-dependently superior to those in ligustrazine group (P<0.05 or P<0.01). CONCLUSION: Ligustrazine ferulate protects rats against myocardial ischemia-reperfusion injury. Its anti-apoptotic effect may be related to up-regulation of Bcl-2 and down-regulation of Bax.     

Expression of Toll-like receptor 3 in myocardium in experimental autoimmune myocarditis

AIM: To establish an animal model of experimental autoimmune myocarditis (EAM) in BALB/c mice and to investigate the expression and significance of Toll-like receptor 3 in mouse EAM. METHODS: BALB/c mice were immunized with cardiac myosin extracted from porcine ventricular myocardium covered by complete freund’s adjuvant (CFA) on 0 d and 7 d, then divided into EAM group (n=20) and poly (I∶C) group (n=24). Control mice (n=18) were immunized with CFA only. Serum and myocardium samples were collected at 14 d and 21 d after the first immunization. HE staining was used to identify the areas of inflammation. The myosin IgG antibody was examined by indirect ELISA assay. The changes of TLR3 protein and mRNA expression in myocardial tissue were measured by immunohistochemistry and real time-PCR. RESULTS: Compared to control group, immunohistochemistry results showed that there was positive expression of TLR3 in the myocardium of mice with EAM and the mRNA of TLR3 were more than 20 times increased in a time-dependent manner at 12 h after poly (I∶C) injection (P<0.05). The expression of interferon beta mRNA in EAM group was more than 14 times as many as basal expression, that of tumor necrosis factor alpha was more than 18 times (P<0.05). CONCLUSION: The expression of Toll-like receptor 3 in myocardium is up-regulated in experimental autoimmune myocarditis. The inflammatory response to cardiac myosin may associate with the TLR3 signal transduction pathway.     

Anti-apoptosis effect of liraglutide on islet via regulating microRNA-375

AIM: To observe the anti-apoptosis effect of liraglutide on the islet through microRNA-375 (miR-375) for providing additional pharmacodynamic evidence for its clinical application. METHODS: For in vitro study, C57BL/KsJ-db/m mice aged 8 weeks served as normal control group. A total of 40 male genetically diabetic C57BL/KsJ-db/db mice at the same age were randomly divided into diabetic control group （the db/db mice were injected subcutaneously with equivalent amount of saline) and liraglutide group (the db/db mice were injected subcutaneously with liraglutide at dose of 300 μg·kg^-1·d^-1). After 8 weeks of administration, body weight (BW) was measured and blood was collected for detection of fasting blood glucose (FBG), fasting blood insulin (FINS), triglyceride (TG), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). Before sacrifice, intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance test (ITT) were conducted. The histopathological features in the islet tissue were examined with HE staining. The apoptosis in the islet tissue was detected by TUNEL staining. The protein levels of caspase-3, Bcl-2 and Bax were determined by Western blot. The level of miR-375 in the islet tissue was detected by qPCR. Forin vitro study, the MIN-6 cells were cultured and divided into control group (incubated with equivalent amount of solvent), miR-375 mimic group and miR-375 mimic+ liraglutide group. The cell viability was examined by MTT assay. The protein levels of caspase-3, Bcl-2 and Bax were detected by Western blot. RESULTS: In thein vitro study, compared with control group, the levels of BW, FBG, FINS, TC, TG and LDL-C were decreased significantly in liraglutide group. The islet apoptosis was reduced by the administration of liraglutide. The expression of Bcl-2 was up-regulated significantly, while the protein levels of caspase-3 and Bax were down-regulated significantly in liraglutide group. The level of miR-375 was decreased significantly. In the in vitro study, the cell viability was decreased in miR-375 mimic group and increased in miR-375 mimic+liraglutide group. Moreover, the expression of Bcl-2 was decreased and the protein levels of caspase-3 and Bax were increased with the incubation of miR-375 mimic, while the expression of Bcl-2 was increased and the protein levels of caspase-3 and Bax were decreased with the co-incubation of miR-375 mimic and liraglutide. CONCLUSION: Liraglutide attenuates islet apotosis, and the mechanism may be associated with its effects of reducing the elevated level of miR-375 in islet tissues.     

Effects of Panax quinquefolium saponin on mitochondrial membrane potential and cardiomyocyte apoptosis in ischemia/reperfusion rats

AIM：To investigate whether mitochondrial membrane potential (ΔΨm) and the mitochondrial apoptotic pathway are involved in the protective mechanism of Panax quinquefolium saponin (PQS) against cardiomyocyte apoptosis after ischemia/reperfusion (I/R) injury in rat myocardium. METHODS：Ninety healthy male SD rats were randomly divided into sham group, I/R group, PQS (200 mg·kg-1·d-1) +I/R group, cyclosporine A (CsA) group, CsA (10 mg·kg-1) +I/R group and PQS +CsA +I/R group. The model of myocardial I/R injury in vivo was established by ligating the left anterior descending artery (LAD) for 30 min followed by 120 min of reperfusion in the rats. The serum activity of lactate dehydrogenase (LDH) was measured by automatic chemistry analyzer. The myocardial infarct size was measured by Evans blue and 2,3,5-triphenyltetrazolium chloride (TTC) staining. Cardiomyocyte apoptosis was detected by in situ TDT-mediated dUTP nick end labeling (TUNEL). The protein levels of Bcl-2, Bax, cleaved caspase-3 and cytosolic cytochrome C were determined by Western blotting. ΔΨm was measured by laser scanning confocal microscopy and fluorescence microplate reader. RESULTS：Compared with I/R group, the serum content of LDH,the infarction size in PQS+I/R group, CsA+I/R group and PQS+CsA+I/R group and the myocardial apoptotic index were decreased. Compared with I/R group, the fluorescence intensity of mitochondria after JC-1 staining was enhanced in PQS+I/R group, CsA+I/R group and PQS+CsA+I/R group, and the relative fluorescence units (RFU) of ΔΨm were improved in those 3 groups. In PQS+I/R group, CsA+I/R group and PQS+CsA+I/R group, the protein expression of Bcl-2 was increased, and that of Bax was decreased compared with I/R group. Moreover, in those 3 groups, the protein levels of cleaved-caspase-3 and cytosolic cytochrome C were decreased compared to I/R group, respectively. CONCLUSION：PQS attenuates myocardial injury and cardiomyocyte apoptosis during I/R, and the protective mechanisms of PQS were associated with the modulation of ΔΨm and the inhibition of mitochondrial apoptosis pathway.     

Preventive effects of Clostridium butyricum on gastric ulceration induced by pylorus ligature in mice

AIM: To investigate the preventive effects of Clostridium butyricum (C. butyricum) on the type of pylorus ligated gastric ulcer (GU) in mice and the underlying mechanisms. METHODS: ICR mice were randomly divided into 4 groups: sham operation group, model group, C. butyricum pretreatment group and omeprazole pretreatment group. Gastric pyloric ligation was adopted to establish GU model in mice. The gastric juice was collected to measure the content of gastric free mucus, the pH of gastric juice and the activity of pepsin. The gastric tissues were collected for routine HE staining to observe the pathological changes. The content of glycogen was detected by PAS staining. The protein expression of Bax and Bcl-2 in the gastric mucosa was also assessed by immunohistochemical staining. RESULTS: The HE and PAS staining showed that the C. butyricum pretreatment obviously attenuated the mucosa lesion induced by ligation. Compared with model group, the pH of gastric juice was significantly raised. The activity of pepsin fell off in C. butyricum group, which was lower than that in omeprazole group. In comparison with model group, the content of gastric free mucus was dramatically increased and PAS staining showed a significant rise in C. butyricum group, but not in omeprazole group. The protein expression of Bax was decreased and the protein expression of Bcl-2 was upgraded in C. butyricum group than those in model group. CONCLUSION: C. butyricum protects gastric mucosa against the challenge of pylorus ligation in mice and its mechanism may be related to inhibiting gastric acid secretion and the activation of pepsin, increasing the production of gastric free mucus, strengthening the expression of bcl-2 gene and inhibiting the expression of bax gene.     

miRNA-7-mediated Bax/Bcl-2 expression promotes apoptosis of human nasopharyngeal carcinoma CNE-1 cells

AIM: To investigate the relationship of microRNA-7 (miRNA-7) over-expression and Bax/Bcl-2 expression in human nasopharyngeal carcinoma CNE-1 cells.METHODS: The CNE-1 cells were transfected with miRNA-7 mimics using Lipofectamine 2000. The expression of miRNA-7 was detected by real-time PCR. CCK-8 assay and Hoechst 33258 staining were used to detect the cell activity and apoptosis. The expression of Bax/Bcl-2 at mRNA and protein levels was determined by real-time PCR and Western blot. RESULTS: The expression of miRNA-7 was increased significantly in the CNE-1 cells compared with negative control group and mock group (P<0.01). The activity of CNE-1 cells were extremely decreased after tansfected with miRNA-7 mimics (P<0.01). The typical apoptotic nuclear morphological changes were observed in the CNE-1 cells under the fluorescence microscope with Hoechst 33258 staining. The expression of Bax at mRNA and protein levels was significantly increased compared with the other 2 groups (P<0.01), while the Bcl-2 expression at mRNA and protein levels was significantly down-regulated (P<0.01).CONCLUSION: Over-expression of miRNA-7 significantly inhibits the growth and promotes the apoptosis of nasopharyngeal carcinoma CNE-1 cells by increasing the expression of Bax and down-regulating Bcl-2.     

Panax quinquefolium saponins protect rat myocardium from ischemia/reperfusion injury through attenuating excessive endoplasmic reticulum stress

AIM: To investigate whether excessive endoplasmic reticulum stress (ERS) is involved in the protective mechanism of Panax quinquefolium saponins (PQS) against ischemia/reperfusion (I/R) injury in rat myocardium. METHODS: The model of myocardial I/R injury in vivo was made by ligating the left anterior descending artery for 45 min followed by 24 h of reperfusion in SD rats. The hemodynamics and serum content of cardiac troponin T (cTnT) were measured. The myocardial infarct size was measured by Evans blue and 2, 3, 5-triphenyltetrazolium chloride (TTC) staining. Cardiomyocyte apoptosis was detected using in situ TDT-mediated dUTP nick end labeling (TUNEL). The protein levels of glucose-regulated protein 78 (GRP78), calreticulin (CRT), C/EBP homologous protein (CHOP), caspase-12, apoptosis-associated proteins Bax and Bcl-2 were determined by Western blotting. RESULTS: Compared with I/R group, the mean arterial pressure in PQR+IR group was decreased by 32.0%, and left ventricular±dp/dtmax was increased by 64.0% and 35.0%, respectively.The serum content of cTnT was decreased by 53.3%, the percentage of area of necrosis (AN)/area at risk (AAR) was reduced by 65.5% and the apoptosis rate was decreased by 54.9%.The myocardial pathological changes were improved. Bcl-2 protein expression was increased by 110.0% and that of Bax was decreased by 47.8%. CRT protein expression was decreased by 43.4 %, CHOP protein expression and the protein level of cleaved caspase-12 were decreased by 38.6% and 23.7% in PQS+I/R group. CONCLUSION: PQS alleviates I/R injury in myocardium by inhibition of excessive ERS.     

Relationship between histone H3K36 trimethylation and acute renal injury induced by ischemia/reperfusion

AIM: To observe the expression change of H3K36 trimethylation (H3K36me3) in acute kidney injury (AKI) induced by ischemia/reperfusion (IR) and analyze its correlation with SMYD2 and renal injury, and to provide a new target for clinical treatment of IR-AKI. METHODS: The ICR mice (n=30) were randomly divided into IR group (n=15) and sham operation group (sham group, n=15). The AKI model was established by clamping bilateral renal pedicles for 45 min. The serum and renal tissues of the mice were collected after the model was established for 24 h. The levels of blood urea nitrogen (BUN) and serum creatinine (SCr) were detected by biochemical method. The pathological changes of the kidney were observed by HE staining. The changes of NGAL and cleaved caspase-3 were observed by immunohistochemical (IHC) staining. The protein levels of NGAL, SMYD2, H3K36me3, p-P53, P53, cleaved caspase-3, Bax, Bcl-2, STAT3, p-STAT3, JNK and p-JNK1/2/3 in the renal tissues were determined by Western blot. The relationship between H3K36me3 and SMYD2/NGAL was analyzed by Pearson correlation method. RESULTS: Compared with sham group, BUN and SCr levels of the mice in IR group were significantly increased (P<0.05). HE staining showed significant edema, abscission and necrosis in renal tubular epithelial cells of the micc in IR group, and abscission of brush border and large amount of cell debris in the lumen were also observed. The IHC staining results showed that the protein levels of NGAL and cleaved caspase-3 in IR group were significantly increased. The results of Western blot showed that the protein levels of NGAL, SMYD2, H3K36me3, p-P53, cleaved caspase-3, Bax, STAT3, p-STAT3, JNK and p-JNK1/2/3 in IR group were significantly up-regulated (P<0.05), while the Bcl-2 levels were significantly down-regulated (P<0.05). The correlation analysis showed that H3K36me3 was positively correlated with the levels of SMYD2 and NGAL. CONCLUSION: H3K36me3 is closely related to SMYD2 and renal injury in IR-AKI mice, and the up-regulated expression of H3K36me3 may be involved in the regulation of IR-AKI occurrence and development together with the activation of STAT3 and JNK signaling pathways.     

Effects of carvedilol on murine viral myocarditis

AIM: To observe the effects of carvedilol on murine viral myocarditis model. METHODS: A total of 188 inbred male BALB/c mice of 4-6 weeks were divided into 4 groups: myocarditis group (group C, n=60), metoprolol treatment group (group M, n=60), carvedilol treatment group (group K, n=60), control group (group B, n=8). Myocardial histopathololgic changes were observed. The concentrations of cardiac troponin I (cTn-I) were detected by chemiluminescence immunoassay (CLIA). Western blotting was performed to analyze the contents of phosphorylated p38MAPK in myocardium. RESULTS: Metropolol and carvedilol lightened myocardial histopathololgic changes at acute stage, decreased cTn-I concentrations and myocardial phosphorylated p38MAPK value compared with myocarditis group. Treatment with carvedilol was more effective than treated with metropolol on those indexes. CONCLUSION: Carvedilol protects against viral myocarditis by inhibition of p38MAPK signal transduction pathway through blockade of β1 and β2 adrenergic receptors.     

Change of calcium sensing receptor expression and apoptotic pathways in myocardial infarction rat induced by isoprel

AIM:To observe the change of calcium sensing receptor (CaSR) expression and apoptotic pathways in myocardial infarction rat induced by isoprel.METHODS: The myocardial infarction rat models were prepared by subcutaneous injection of isoprel (ISO 200 mg·kg-1·d-1 for 2 d). Wistar rats were divided into three groups randomly: ① Control group; ② ISO/1d group; ③ ISO /2d group. The expressions of CaSR, 〖STBX〗bcl-2, bax〖STBZ〗 and caspase-3 mRNA and protein were analyzed by RT-PCR and Western blotting, respectively. Apoptotic cells were measured by TUNEL staining assay. The morphological and ultrastructural changes were observed under optical microscope and electronic microscope. The activity of LDH, CK, SOD and the content of MDA were assayed with ultraviolet spectrophotometer. The level of troponin(cTnT) was observed by chemical immunofluoresence.RESULTS: Compared with control group, the activity of LDH and CK, the content of MDA and cTnT, the apoptosis index and the expression of CaSR, Bax and caspase-3 were reached the highest level, but the SOD activity and Bcl-2 expression were decreased. The myocardial ultrastructural injury was aggravated in the ISO/1d group. The change of above parameters in ISO/2d group was between control and ISO/1d group.CONCLUSION:The increased expression of CaSR is involved in rat myocardial infarction induced by isoprel, which is related with oxidative stress and apoptosis.     

Regulatory effect of miR-146 on diabetic cardiomyopathy

AIM: To investigate the role of microRNA-146 (miR-146) in the pathogenesis of diabetic cardiomyopathy (DCM), and to observe the expression levels of miR-146 and its downstream target genes. METHODS: Male C57BL/6 mice (n=60) were randomly divided into experimental group (DCM, n=30) and control group (control, n=30). The mice in DCM group were intraperitoneally injected with low dose (50 mg/kg) of streptozo-tocin (STZ) to induce diabetic myocardial model, and the mice in control group were given intraperitoneal injection of citrate buffer. At the end of 12 weeks, the hearts were removed, HE and Masson staining were performed to observe the cardiac pathological changes. RT-qPCR were used to detect the expression of miR-146 a and miR-146b and the the mRNA expression of related downstream genes interleukin-1 receptor-associated kinase 1 (IRAK1) and TNF receptor-associated factor 6 (TRAF6). Western blot was used to determined the protein levels of IRAK1 and TRAF6. RESULTS: At the end of 12 weeks, HE staining showed the hypertrophy and structural disorder of the myocardial cells in DCM group. Masson staining showed that the collagen fibers of myocardium were increased in DCM group; RT-qPCR showed that the levels of miR-146a and miR-146b in DCM group were significantly decreased compared with control group (P<0.01). The mRNA levels of IRAK1 was increased (P<0.01), and the mRNA levels of TRAF6 was declined (P<0.01). Western blot showed that compared with control group, the protein expression of IRAK1 was increased in DCM group, and the protein expression of TRAF6 was decreased with statistically significant.CONCLUSION: miR-146 may involve in the occurrence and development of diabetic cardiomyopathy by regulating inflammatory reactions and targeting IRAK1.     

Aerobic exercise protects cardiac function of T2DM mice by activation of PI3K (p110α)/Akt signaling pathway

AIM: To study the protective effect of aerobic exercise on cardiac dysfunction in mice and its mechanism, and to provide theoretical and practical basis for the exercise therapy of diabetic cardiac dysfunction.METHODS: The mice were divided into normal control non-exercise (NNC) group, normal control exercise (ENC) group, diabetic non-exercise (NDM) group and diabetic exercise (EDM) group. At the end of the experiment, the cardiac function was evaluated by echocardiography. The pathological changes of the myocardial tissues and the development of fibrosis were observed. The mRNA expression of ANP, and the protein levels of PI3K (p110α) and Akt were determined. RESULTS: The decrease in cardiac function of diabetic mice was observed, and the cardiac function recovered after exercise intervention (P<0.05). Under light microscope with HE and Masson staining, the myocardial structure in NDM group was in extreme disorder, cell arrangement was not neat, and the degree of fibrosis increased, but the myocardial damage was improved in ENC group. Compared with NNC group, the mRNA expression of ANP in the myocardium of diabetic mice was up-regulated (P<0.05). The protein levels of PI3K (p110α) and Akt were decreased (P<0.05), and the cascade was inactivated. Compared with NDM group, the mRNA expression of ANP was down-regulated and the protein levels of PI3K (p110α) and Akt were up-regulated in EDM group (P<0.05). CONCLUSION: Diabetes results in myocardial damage in mice, and reduces cardiac function. Exercise intervention alleviates the heart dysfunction induced by high glucose via activating PI3K(p110α)/Akt signaling pathway to protect the structure and function of the myocardium.     

Protective effects of basic fibroblast growth factor (bFGF) against to myocardial ischemia in rats

AIM: To study the protective effects of basic fibroblast growth factor (bFGF) on myocardial ischemia in rats and their underlying mechanism. METHODS: A rat myocardial ischemic injury model was established by left coronary artery ligation. The rats were killed at 2 h, 4 h, 8 h after coronary artery occlusion. The samples of blood and myocardium were collected for observing the expression of Bcl-2 and Bax in myocardial cells and the changes of superoxide dismutase (SOD) or myocardial enzymes. RESULTS: The amount of Bcl-2 protein expression of myocardial cells in ischemia + bFGF group was significantly higher than that in ischemia+saline group (P＜0.01) at 2 h, 4 h after coronary artery occlusion. However, the change of Bax protein expression was reversed (P＜0.05). The activity of SOD in ischemia+bFGF group was higher than that in ischemia+saline group, and the changes of LDH, CK-MB and α-HBDH in ischemia+bFGF group were reversed (P＜0.05) in serum. CONCLUSION: bFGF has protective roles against myocardial ischemia in rats.