Inhibition of endotoxin on the function of cardiac sarcoplasmic reticulum in rats / 解放军医学杂志

Objective To observe the enzymatic changes of myocardial sarcoplasmic reticulum in rats after injecting endotoxin (LPS), and provide basic research results for the future study of myocardial sarcoplasmic reticulum dysfunction caused by LPS in rats. Methods Ten SD rats were randomly divided into blank control group and LPS injection group with 5 rats in each group. In the LPS injection group, endotoxin was injected into the tail vessels of the rats. Results The heart rate (HR) of the LPS injection group increased and was faster than that in the blank control group [(204±18) beat per min vs. (139±10) beat per min on the first day, and (199±22) beat per min vs. (143±17) beat per min on the next day, both P values were less than 0.05]. The mean arterial pressure (MAP) was lower than that of the blank control group on the first day [(87±12) mmHg vs. (102±7) mmHg, P<0.05]. Under light and electron microscope, the myocardial cells of rats with LPS injection were loosely arranged, with intercellular infiltration with inflammatory cells, muscle fibers broken, and difficult to identify the morphology of mitochondria and sarcoplasmic reticulum. Quantitative PCR results showed that after endotoxin injection, troponin (CASQ1), sodium-calcium exchanger (NCX), calmodulin phosphatase 1 (ppplCa), phospholipid protein (PLN), sarcoplasmic reticulum Ca2+-ATPase (SERCA2) increased significantly (P<0.05). Conclusion Endotoxin can inhibit cardiomyocyte function by affecting the activity of sarcoplasmic reticulum calcium regulatory protein-related enzymes through various mechanisms.

Effect of 5-AZA-2'-dC on angiotensin Ⅱ-induced cardiomyocyte hypertrophy / 中华急诊医学杂志

Objective To investigate the effect of 5-AZA-2'-dC on Angiotensin Ⅱ (Ang Ⅱ)-induced cardiomyocyte hypertrophy.Methods Cultured cells derived from neonatal heart of rat were divided into 5 groups:normal control,hypertrophic group,5-AZA-2'-dC treatment group,and 5-AZA-2'-dC pretreatment group.Neonatal rat cardiomyocyte hypertrophic response was assayed by the size of cardiomyocytes and atrial natriuretic polypeptide (ANP) expressive level.The level of sarcoplasmic reticulum Ca2+ ATPase (SERCA2a),total calmodulin kinase Ⅱ (CaMK Ⅱ) and phospho-CaMK Ⅱ (p-CaMK Ⅱ) detected by Western blot.The intracellular calcium changes of cardiomyocytes were imaged by confocal fluorescent microscopy.Results Cells treated with Ang Ⅱ at 10-6 mol/L for 48 h were chosen as hypertrophic cardiomyocyte model.The mRNA expression and protein level of ANP were significantly decreased in the treatment and pretreatment groups compared with hypertrophic group.The protein level of SERCA2a was significantly decreased in the hypertrophic group,and increased in the treatment and pretreatment group compared with hypertrophic group.The protein level of SERCA2a was significantly decreased in the hypertrophic group,and increased in the treatment and pretreatment group compared with hypertrophic group,whereas phospho-CaMK Ⅱ showed an opposite change tendency.The time required for increasing and declining to half of the intracellular calcium peak value were both delayed in hypertrophic group,as the treatment and pretreatment groups showed shorter time required compared with hypertrophic group.Conclusion 5-AZA-2'-dC could inhibit Ang Ⅱ-induced cardiomyocyte hypertrophy which might be related to regulate SERCA2a expression.Increased SERCA2a expression may maintain the calcium homeostasis through shortening the time of transfer Ca2+ from the cytosol of the cell to the lumen of the sarcoplasmic reticulum.

Hydrogen peroxide attenuates refilling of intracellular calcium store in mouse pancreatic acinar cells

Intracellular calcium (Ca²⁺) oscillation is an initial event in digestive enzyme secretion of pancreatic acinar cells. Reactive oxygen species are known to be associated with a variety of oxidative stress-induced cellular disorders including pancreatitis. In this study, we investigated the effect of hydrogen peroxide (H₂O₂) on intracellular Ca²⁺ accumulation in mouse pancreatic acinar cells. Perfusion of H₂O₂ at 300 µM resulted in additional elevation of intracellular Ca²⁺ levels and termination of oscillatory Ca²⁺ signals induced by carbamylcholine (CCh) in the presence of normal extracellular Ca²⁺. Antioxidants, catalase or DTT, completely prevented H₂O₂-induced additional Ca²⁺ increase and termination of Ca²⁺ oscillation. In Ca²⁺-free medium, H₂O₂ still enhanced CCh-induced intracellular Ca²⁺ levels and thapsigargin (TG) mimicked H₂O₂-induced cytosolic Ca²⁺ increase. Furthermore, H₂O₂-induced elevation of intracellular Ca²⁺ levels was abolished under sarco/endoplasmic reticulum Ca²⁺ ATPase-inactivated condition by TG pretreatment with CCh. H₂O₂ at 300 µM failed to affect store-operated Ca²⁺ entry or Ca²⁺ extrusion through plasma membrane. Additionally, ruthenium red, a mitochondrial Ca²⁺ uniporter blocker, failed to attenuate H₂O₂-induced intracellular Ca²⁺ elevation. These results provide evidence that excessive generation of H₂O₂ in pathological conditions could accumulate intracellular Ca²⁺ by attenuating refilling of internal Ca²⁺ stores rather than by inhibiting Ca²⁺ extrusion to extracellular fluid or enhancing Ca²⁺ mobilization from extracellular medium in mouse pancreatic acinar cells.

Shen-Fu Injection () alleviates post-resuscitation myocardial dysfunction by up-regulating expression of sarcoplasmic reticulum Ca(2+)-ATPase / 中国结合医学杂志

<p><b>OBJECTIVE</b>To compare the effect of Shen-Fu Injection (SFI) and epinephrine on the expression of sarcoplasmic reticulum Ca(2+) ATPase 2a (SERCA2a) in a pig model with post-resuscitation myocardial dysfunction.</p><p><b>METHODS</b>Ventricular fibrillation (VF) was electrically induced in Wu-zhi-shan miniature pigs. After 8 min of untreated VF and 2 min of cardiopulmonary resuscitation (CPR), all animals were randomly administered a bolus injection of saline placebo (SA group, n=10), SFI (0.8 mg/kg, SFI group, n=10) or epinephrine (20 μg/kg, EPI group, n=10). After 4 min of CPR, a 100-J shock was delivered. If the defibrillation attempt failed to attain restoration of spontaneous circulation (ROSC), manual chest compressions were rapidly resumed for a further 2 min followed by a second defibrillation attempt. Hemodynamic variables were recorded, and plasma concentrations of catecholamines were measured. Adenylate cyclase (AC), cyclic adenosine monophosphate (cAMP) and the expressions of β1-adrenoceptor (AR) and SERCA 2a were determined.</p><p><b>RESULTS</b>Cardiac output, left ventricular dp/dtmax and negative dp/dtmax were significantly higher in the SFI group than in the SA and EPI groups at 4 and 6 h after ROSC. The expression of β1-AR and SERCA2a at 24 h after ROSC were significantly higher in the SFI group than in the SA and EPI groups (P<0.05 or P<0.01).</p><p><b>CONCLUSIONS</b>The administration of epinephrine during CPR decreased the expression of SERCA2a and aggravated postresuscitation myocardial function (P<0.01). SFI attenuated post-resuscitation myocardial dysfunction, and the mechanism might be related to the up-regulation of SERCA2a expression.</p>

Platelet derived growth factor down-regulated sarcoplasmic reticulum Ca2+atpase to promote the phenotype modulation of human airway smooth muscle cells / 实用医学杂志

Objective To investigate of the effect and mechanisman of SERCA2 on the phenotype modulation of HASMCs. Methods HASMCs were starved for 5 days and divided into different groups ,then we observed morphology change of the cells from the microscope and detected a-actin、SERCA2 and p-ERK by Western Blot,cells proliferation was observed by CCK-8 method. Results Compared with the control group,PDGF could reduce a-actin of HASMCs and increased the cells proliferation ability ,TSG could significantly inhibit the effect (P<0.01), PDGF could also significantly inhibit SERCA2 protein and increased the expression p-ERK (P<0.01), while U0126 significantly inhibited the effect (P < 0.01). Conclusion PDGF may induce HASMCs phenotype modulation through the regulation of SERCA2 and p-ERK.

Liguzinediol exerts positive inotropic effect by enhancing Ca 2+release from sarcoplasmic reticulum mediated by sarcoplasmic reticulum Ca2+ATPase / 中国药理学与毒理学杂志

OBJECTIVE To explore kinetic features and its underlying mechanism of the positive inotropic effect of liguzinediol(LZDO)in rats. METHODS ①An In vivo study was made to record the effect of LZDO 20 mg · kg-1 injected for 30 consecutive min from the left external jugular vein on pressure-volume relationships. ②Ex vivo study was used to record the antagonistic effect of LZDO on reduced contractility induced by caffeine. Caffeine and LZDO were perfused as follows:normal perfusion solution, caffeine 0.5 mmol · L-1,and then caffeine 0.5 mmol · L-1+LZDO 100 μmol · L-1. ③ Ca2+ transient from cardiomyocyte sarcoplasmic reticulum (SR) was measured to analyze the effect of LZDO on Ca2 +release blocked by thapsigargin. Thapsigargin and LZDO were perfused as follows:normal perfusion solution,thapsigargin 2 μmol · L-1,and then thapsigargin 2 μmol · L-1+LZDO 100 μmol · L-1.④The SR vesicles were prepared and the effect of LZDO(1,10 and 100μmol·L-1)on sarcoplasmic reticulum Ca2+ATPase(SERCA2a)activity was determined according to the ultramicro-Ca2+-ATP enzyme kit. RESULTS ① LZDO 20 mg · kg- 1 significantly reduced the end-systolic volume (Ves) and enhanced the end-systolic pressure (Pes),stroke volume (SV),ejection fraction (EF),cardiac output(CO),peak rate of rise of left ventricular pressure(+dp/dtmax)and stroke work(SW)(P<0.05). However,LZDO 20 mg · kg-1 did not significantly change the heart rate(HR )or the end-diastolic volume (Ved). ② Caffeine 0.5 mmol · L- 1 significantly enhanced HR,left ventricular developed pressure (LVDP ),and+dp∶dtmax at 5 min after caffeine and decreased at 30 min. However,LZDO 100μmol·L-1 restored the reduced HR,LVDP,and+dp/dtmax induced by caffeine at 30 min(P<0.05).③Thapsigargin 2μmol·L-1 significantly reduced the SR Ca2+transient from perfusion solution group(100±5)%to(51± 5)%(P<0.05) and LZDO 100 μmol · L-1 failed to restore the decreased Ca2+ transient〔(49 ± 4)%〕. Normalized Ca2+transients were reduced by thapsigargin 2μmol·L-1 and thapsigargin 2μmol·L-1+LZDO 100 μmol · L-1. ④ LZDO(10 and 100 μmol · L-1)significantly increased the activities of SERCA2a in perfusion solution group 0.98±0.10 to 1.17±0.20 and (1.43±0.09)μmol Pi·g-1·h-1,respectively(P<0.05). CONCLUSION LZDO can enhance SR Ca2+ gradient by activating the SERCA2a and might be developed to serve as a potential positive inotropic agent in clinical settings.

The relationship between sarcoplasmic reticulum Ca2+modulation proteins and postresuscitation myocardial dysfunction / 中华危重病急救医学

Objective To investigate the relationship between sarcoplasmic reticulum Ca2+modulation proteins and postresuscitation myocardial dysfunction. Methods Thirty-eight SPF male Sprague-Dawley (SD) rats were randomly divided into control group(n=12)and cardiac arrest(CA)group(n=26). CA was induced by intravenous bolus of potassium chloride(40μg/g),and cardiopulmonary resuscitation(CPR)was conducted 8 minutes later. No CA was induced in control group except catheter placement for monitoring cardiopulmonary parameters after anesthesia. Invasive hemodynamic parameters were monitored for 1 hour after CPR. Echocardiogram was performed to evaluate cardiac function. Myocardial samples were harvested 5 minutes and 1 hour after restoration of spontaneous circulation (ROSC),and sarcoplasmic reticulum Ca2+ ATPase (SERCA2a),phosphorylated phospholamban (p-PLB) and rynodine receptor(RyR)were determined by Western Blot. Results ROSC rate of CA group was 92.3%(24/26),and mean recovery time was (68 ±39)seconds. Cardiac function was significantly impaired in CA group at 1 hour after resuscitation, and ejection fraction, fraction shortening (FS), the maximal rate of left ventricular pressure increase/decline (±dp/dt max)were significantly decreased compared with those in control group 〔ejection fraction:0.548±0.060 vs. 0.809±0.043,F=71.692,P=0.000;FS:(34.4±4.4)%vs. (46.0±3.5)%,F=55.443,P=0.000;+dp/dt max(mmHg/s):4 718±743 vs. 7 098±394,P0.05). Conclusions The impairment of the p-PLB is closely related to postresuscitation myocardial dysfunction.

Diabetes Reducing the Intensity of Sarcoplasmic Reticulum Ca2+-ATPase-SUMOylation of Myocardium in Experimental Rats / 中国循环杂志

Objective: To investigate the effect of diabetes on the intensity of sarcoplasmic reticulum Ca2+-ATPase (SERCA2a)-SUMOylation and SERCA2a activity of myocardium in experimental rats. Methods: The 8 weeks old SD rats were divided into 2 groups, Diabetic group, with diet-induced type 2 diabetic rats and Control group, with normal rats. The systolic and diastolic cardiac functions were evaluated by echocardiography and left ventricular pressure measurement. The intensity of SERCA2a-SUMOylation was examined by co-immunoprecipitation and SUMOylation kit. Results: Compared with Control group, Diabetic group had decreased systolic and diastolic cardiac functions, especially for diastolic function;decreased SERCA2a protein expression and intensity of SUMOylation;decreased SUMOylation E2 (Ubc9 ) protein expression. The protein levels of SUMO1, SAE1 and SAE2 were similar between 2 groups. Conclusion: The intensity of SERCA2a-SUMOylation and Ubc9 decreased in diabetic myocardium which implies that SERCA2a-SUMOylation and Ubc9 were closely related to the damage of diabetic myocardium in experimental rats.

Phospholamban antisense RNA improves SR Ca2+-ATPase activity and left ventricular function in STZ-induced diabetic rats / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the effect of phospholamban antisense RNA (asPLB) on sarcoplasmic reticulum Ca2+-ATPase activity and cardiac function in rats with diabetes mellitus (DM) mediated by recombinant adeno-associated virus (rAAV) vector.</p><p><b>METHODS</b>Six weeks after the induction of DM by streptozotocin injected intraperitoneally, the rats were divided into three groups, namely: DM-rAAV-asPLB group, DM-saline group and DM group (control group). The rats in the DM-rAAV-asPLB group were intramyocardially injected with rAAV-asPLB, the rats in the DM-saline group were injected with saline, and those in the control group did not receive any treatment. Six weeks after gene transfer, the expressions of PLB protein and PLB phosphorylation were detected by Western-blot, while the activity of sarcoplasmic reticulum (SR) Ca2+-ATPase and left ventricular function were measured.</p><p><b>RESULTS</b>The PLB protein expression level was significantly higher whereas the PLB phosphorylation, SR Ca2+-ATPase activity and left ventricular function were significantly lower in the DM-saline group than in the control group. No significant difference was found in PLB protein expression level, PLB phosphorylation or SR Ca2+-ATPase activity between the DM-rAAV-asPLB group and the control group. The left ventricular function in the DM-rAAV-asPLB group was poorer than in the control group and was better than in the DM-saline group.</p><p><b>CONCLUSION</b>rAAV-asPLB can down-regulate PLB protein expression and up-regulate PLB phosphorylation and SR Ca2+-ATPase activity, thus contributing to the improvement of in vivo left ventricular function.</p>

Safety of Sarcoplasmic Reticulum Ca2+-ATPase Gene Transfer by Intramyocardium Administration in Chronic Heart Failure Beagles / 中国康复理论与实践

@#ObjectiveTo assess the safety of intramyocardium injection of sarcoplasmic reticulum Ca2+-ATPase (SERCA2a) to rescue chronic heart failure beagles. MethodsThe heart failure beagles were assessed with myocardium enzymology, cAMP content of myocardium, myocardial oxygen consumption, arrhythmia, systemic inflammation factors, and the function of liver and kidney after SERCA2a gene transferred. ResultsThere were no increase of cAMP content, no more arrhythmia, myocardial oxygen consumption, no apparente systemic inflammation, and no injures to hepatic and renal function. ConclusionOverexpression of SERCA2a by intramyocardium injection is relatively safe.

The changes and significance in mRNA expressions of diaphragmatic cytoskeletal proteins and sarcoplasmic reticulum Ca~(2+)-ATPase in adriamycin-induced cytotoxicity in rats / 中国药理学通报

Aim To observe the changes of diaphragm contractility and cytoskeletal proteins titin,nebulin and sarcoplasmic reticulum Ca~(2+)-ATPase gene expressions in adriamycin-induced cytotoxicity in rats.Methods The animal models of diaphragm damage were duplicated by injecting adriamycin into abdominal cavity one time.Forty male sprague-dawley rats were randomly divided into four groups(n=10):Three groups received adriamycin in low,middle and high dosage(10,20 and 40 mg·kg~(-1))respectively.Meanwhile,the normal saline was given to rats in control groups.Three days later,these rats were killed,and the diaphragm was removed by thoracotomy.The diaphragm contractility was assessed in isolated diaphragm strips perfusion by these paramemters including peak twitch tension(Pt),maximum tetanic tension(Po),time to peak contraction(CT),half relaxaion time(1/2RT),maximal rates of contraction(+dt/dt_(max))and maximal rates of relaxation(-dt/dt_(max)).The expressions of titin,nebulin and sarcoplasmic reticulum Ca~(2+)-ATPase(SERCA)at mRNA level were detected by RT-PCR analysis.Results In contrast to those in control group,Po,Pt,±dt/dt_(max) in the adriamycin group were lower(P<0.01);CT,1/2RT in the adriamycin group increased significantly(P<0.01).The levels of titin,nebulin and SERCA gene expressions in middle-dose group were lower than those in control group(P<0.01).Conclusions The mRNA levels of titin,nebulin and SERCA of diaphragm are down-regulated in adriamycin-induced cytotoxicity in rats.It may be associated with the decline of diaphragm contractility.

Effects of Gypenosides on Heart Function of Rats with Adriamycin-induced Acute Heart Failure / 中药新药与临床药理

Objective To observe the effects of gypenosides(GP) on cardiac dysfunction induced by adriamycin in rats and to investigate the therapeutic mechanism.Methods Adult male Sprague-Dawley rats were randomly divided into 5 groups:control group,adriamycin(ADR) group,low-,moderate-and high-dose GP groups.The low-,moderate-and high-dose GP groups received GP 100,200 and 400 mg? kg-1? d-1 for five days respectively.Meanwhile,the purified water was given to rats of control group and adriamycin groups.On the sixth day,adriamycin(10 mg? kg-1) was given intraperitoneally(ip) to all the groups except the control rats.At the twenty-fourth hour after administration of adriamycin,the cardiac functions such as left ventricular systolic pressure(LVSP),maximal rates of increase and decrease of left ventricular pressure(? dp/dtmax),as well as the activities of cardiac ATPase,succinic dehydrogenase(SDH) and sarcoplasmic reticulum Ca2+-ATPase(SERCA2a) were measured.Results The impairment of heart function induced by adriamycin was relieved and the activities of cardiac ATPase,SDH and SERCA2a were obviously increased after GP treatment.Conclusion GP have protective effects on cardiac dysfunction induced by adriamycin in rats,and the mechanism may be related to the increase of activities of cardiac ATPase,SDH and SERCA2a.

Effects of fructose-1,6-diphosphate on adriamycin-induced calcium and sarcoplosnic reticulum Ca ~(2+)-ATPase activity in cardiomyocytes of rats / 中国病理生理杂志

AIM: To study the effects of fructose-1,6-diphosphate (FDP) on adriamycin (ADR)-induced calcium and sarcoplasmic reticulum Ca 2+-ATPase activity in cardiomyocytes of rats. METHODS: Rats were treated with ADR by intraperitoneal injection (2 5 mg?kg -1 body weight) once every two days for 11 days, and then ADR-treated rats were intervened by FDP at different dosages (ip) once every other day for 41 days. Enzyme linked immune absorption assay (ELISA) was employed to detect froponin I (CTnI). CK-MB was examined by monoclonal antibody. Intracellular free calcium concentration was measured on fluorescent spectrophotometry and SRCa 2+-ATPase activity was examined by inorganic phosphate. RESULTS: FDP (300, 600, 1 200 mg?kg -1) significantly reduced the levels of CTnI and CK-MB in serum. Decreased calcium and increased SRCa 2+-ATPase activity in cardiomyocytes were also observed when ADR-treated rats were intervened by FDP (P

The value of intrapericardial injection with a trans-diaphrag matic approach in the gene therapy of chronic heart failure rats / 中国病理生理杂志

AIM: To study the feasibility, security a nd validity of the intrapericardial injection with a trans-diaphragmatic approach in chronic heart failure rats and its value in the study of gene therapy for hea rt diseases, and further investigate whether adeno-associated virual gene transf er of sarcoplasmic reticulum Ca 2+-ATPase (SERCA2a) gene can improve ven tricular function in chronic heart failure (HF) rats. METHODS: An animal model of heart failure was obtained by creati ng descending aortic constriction in rats. Recombinant adeno-associated virus, c arrying enhanced green fluorescent protein (EGFP) gene and recombinant adeno-ass ociated virus carrying SERCA2a gene, were respectively injected into pericardium of heart failure rats in different groups (group HF+EGFP and group HF+SERCA2a) by intrapericardial injection with a trans-diaphragmatic approach. After 30 days , hemodynamic parameters were measured and analyzed. Cryosection was analyzed by fluorescence microscopy to examine the expression of green fluorescent protein, and Western blotting was performed to detect the expression of SERCA2a. RESULTS: Green fluorescence was detected in cryosection of the h earts in all rats in group HF+EGFP and the expression of green fluorescent prote in was ubiquitously. The expression of SERCA2a in all rats in group HF+SERCA2a w as more than those in group HF and group HF+EGFP. And overexpression of SERCA2a improved the systolic and diastolic function of heart failure rats significantly and the hemodynamic parameters were similar with those of the controls. CONCLUSION: The intrapericardial injection with a trans-diaphrag matic approach suggests a simple, safe, efficient and cheap technique for the ge ne therapy of chronic heart failure. Gene thransfer of SERCA2a may be a new appr oach for the treatment of chronic heart failure.

Short-term effects of adeno-associated viral gene transfer of SRCA2a on chronic heart failure in rats / 解放军医学杂志

Objective To study the short-term therapeutic effects of adeno-associated viral gene transfer of sarcoplasmic reticulum Ca2+-ATPase (SRCA2a) on chronic heart failure (CHF). Methods The rats were divided into four groups: control group, CHF group, CHF+eGFP group and CHF+SRCA2a group. CHF rats were obtained by creating descending aortic constriction. 0.9% sodium chloride solution, recombinant adeno-associated virus carrying enhanced green fluorescent protein (eGFP) gene, and recombinant adeno-associated virus carrying SRCA2a gene, were respectively injected into pericardium of heart failure rats in different groups by intrapericardial injection via trans-diaphragmatic approach. 10 days after gene transfer, hemodynamic parameters, the protein expression of SRCA2a and the SRCA2a activity were measured and analyzed respectively. Results 10 days after gene transfer, the protein expression and activity of SRCA2a were increased by 80.7% and 89.9% respectively, but still lower than those in the control rats. The heart function was also improved along with the increase of SRCA2a expression and activity. The left ventricular systolic pressure and the maximal rate of decline of left-ventricular pressure in CHF+SRCA2a group were similar with those of the controls. The left ventricular end-diastolic pressure and the maximal rate of rise of left-ventricular pressure were much improved, but did not reach the level of the controls. Conclusions SRCA2a protein levels and activity are significantly decreased in CHF rats. Adeno-associated viral gene transfer of SRCA2a can improve the function of the heart in short term.