Betulin protects against isoproterenol-induced myocardial injury by inhibiting NF-κB signaling and attenuating cardiac inflammation and oxidative stress in rats

Objective:To investigate the cardioprotective potential of betulin in isoproterenol(ISO)-induced myocardial injury in rats.Methods:Wistar rats were divided into five groups(n=10):normal,ISO,nebivolol 5 mg/kg,and betulin(20&40 mg/kg).Nebivolol and betulin were administered orally for 29 days.ISO(85 mg/kg)was administered subcutaneously on day 27 and day 28 to induce myocardial injury.On day 29,blood was collected for determination of cardiac markers,and hemodynamic parameters were investigated.The levels of oxidative stress markers and the gene expressions of apoptotic markers and inflammatory mediators were evaluated.Moreover,2,3,5-triphenyltetrazolium chloride staining and histopathological analysis were also performed.Results:Betulin reduced the size of myocardial infarction,decreased elevated levels of cardiac enzymes,and maintained hemodynamic functions.It also inhibited ISO-induced upregulation of Bax,caspase-3,NF-κB,and IL-6,enhanced endogenous antioxidant enzymes,and reduced lipid peroxidation.Additionally,pretreatment with betulin alleviated myocardial ischemic damage,as reflected by reduced myonecrosis,edema,and inflammatory changes.Conclusions:Betulin exhibits strong cardioprotective activity against ISO-induced myocardial injury by anti-inflammatory,anti-apoptotic,and antioxidant activities.

L-carvone attenuates myocardial injury and dyslipidemia in rats with isoproterenol-induced cardiac hypertrophy

Objective:To explore the therapeutic efficacy of L-carvone from Mentha spicata L.leaf extracts against isoproterenol-induced cardiac hypertrophy in rats.Methods:Isoproterenol(5 mg/kg)was injected intraperitoneally into rats for one month to induce cardiac hypertrophy.L-carvone(25 and 100 mg/kg)was administered orally to treat cardiac hypertrophy.The cardioprotective activity of L-carvone was evaluated by electrocardiogram,histopathological analysis as well as determination of biochemical parameters and enzymatic markers.Results:L-carvone from Mentha spicata L.at 25 and 100 mg/kg ameliorated isoproterenol-induced cardiac hypertrophy,as evidenced by reduced QRS interval on electrocardiogram,and decreased heart weight and heart index.In addition,both doses of L-carvone markedly lowered the levels of glucose,total protein,low-density lipoprotein cholesterol,aspartate transaminase,alanine transaminase,lactate dehydrogenase,creatine kinase MB,troponin-Ⅰ,N-terminal pro-B type natriuretic peptide and triglycerides while increasing high-density lipoprotein cholesterol and lipase level(P<0.05).Moreover,L-carvone alleviated contraction band necrosis,and reorganized the myofibrils with normal striations and myocytes as well as normal nuclei in cardiac histoarchitecture of rats with isoproterenol-induced cardiac hypertrophy.Conclusions:L-carvone from Mentha spicata L.leaf extract can restore abnormal cardiac function and may be further explored as a therapeutic agent against the deleterious effects of cardiac hypertrophy after further evaluation.

Beta-glucan protects against isoproterenol-induced cardiac remodeling by regulating the ACE-AT1R axis and attenuates cardiac inflammation and apoptosis

Objective:To investigate the cardioprotective effect of beta-glucan against isoproterenol-induced cardiotoxicity in rats,and elucidate the underlying mechanism.Methods:Rats were orally pretreated with beta-glucan(40 mg/kg body weight)for 30 d,and isoproterenol(20 mg/100 g body weight)was administered on days 31 and 32.The effects of beta-glucan on markers of cardiac injury,hemodynamic changes,production of proinflammatory cytokines,and the corresponding mRNA expressions were evaluated.In addition,histological analysis was performed.Results:Pretreatment with beta-glucan prevented isoproterenol-induced cardiac injury by preserving the structural and functional integrity of the plasma membrane and attenuating the production of proinflammatory cytokines(NF-κB,TNF-α,IL-6,IL-1β,and IFN-γ)in the heart.Moreover,beta-glucan significantly downregulated the mRNA expression of ACE,AT1R,TNF-α,IL-6,NF-κB,caspase-3,TLR-4,and Bax,and upregulated Bcl-2 in the heart.At the same time,pretreatment with beta-glucan alleviated myocardial damage as reflected in a reduction in myonecrosis,edema,and erythrocyte extravasation with almost imperceptible inflammation.Conclusions:Beta-glucan can protect against isoproterenol-induced cardiotoxicity by attenuating cardiac inflammation and apoptosis and regulating the ACE-AT1R axis,thereby preventing cardiac remodeling.

Naringenin suppresses NLRP3 inflammasome activation via the mRNA-208a signaling pathway in isoproterenol-induced myocardial infarction

Objective:To investigate the cardioprotective effect of naringenin against isoproterenol(ISO)-induced cardiotoxicity in rats.Methods:Rats were divided into five groups:the normal group,the ISO group(85 mg/kg b.w.);the ISO+naringenin(50 mg/kg b.w.)group,the ISO+naringenin(100 mg/kg b.w.)group and the ISO+propranolol(10 mg/kg b.w.)group.Plasma creatine kinase-MB(CK-MB),cardiac troponin T,lactate dehydrogenase,brain natriuretic peptide(BNP),and IL-10,as well as cardiac transforming growth factor-β1(TGF-β1),vascular endothelial growth factor(VEGF)and malondialdehyde(MDA)were examined.In addition,NLRP3 and mRNA-208a expressions were evaluated by RT-PCR analysis.Histopathological examination was also performed to assess cardiac damages.Results:Naringenin treatment significantly decreased plasma lactate dehydrogenase,CK-MB,cardiac troponin T,BNP,and IL-10,as well as cardiac TGF-β1,VEGF,and MDA while increasing p-Akt and superoxide dismutase in ISO-administered rats.It also reduced NLRP3 and mRNA-208a gene expression levels.Furthermore,naringenin improved ISO-induced cardiac damage.Conclusions:Naringenin attenuates myocardial dysfunction in ISO-treated rats by decreasing oxidative stress and increasing cardiac endogenous antioxidant system,which may be modulated partly by improvement of NLRP3 and mRNA-208a gene expression.

A Cardiomyopeptin Preparation Protects against Isoproterenol-Induced Chronic Heart Failure in Rats

The present study investigated the effect of an herbal extract-supplemented cardiomyopeptin preparation (HECP), in the rat model of chronic heart failure. HECP pre-/co-treatment at a daily dose of 0.072 to 0.124 g/kg for 30 days protected against isoproterenol (ISO)-induced chronic myocardial damage in rats in a dose-dependent manner, with the extent of protection, as assessed by plasma cardiac troponin I level, being up to 76%. The cardioprotection afforded by HECP was associated with the enhancement of myocardial mitochondrial antioxidant status, amelioration of plasma parameters on cardiac dysfunction and hypertrophy, as well as an increase in myocardial endothelial nitric oxide synthase activity. Myocardial apoptotic and anti-apoptotic parameters were suppressed and stimulated, respectively. The cardioprotection afforded by HECP was accompanied by an increase in exercise capacity, an indirect functional index of the myocardium, in ISO-challenged rats. In conclusion, HECP may offer a promising prospect in preventing chronic heart failure in human subjects.

Tomato lycopene attenuates myocardial infarction induced by isoproterenol:Electrocardiographic,biochemical and anti-apoptotic study

Objective:To assess the protective effects of lycopene on electrocardiographic,hemodynamic, biochemical and apoptotic changes in isoproterenol induced myocardial infarction.Methods: Myocardial infarction was induced in rats by subcutaneous injection of isoproterenol(200 mg/kg) for two consecutive days at an interval of 24 h.Rats were treated with lycopene(10 mg/kg/day, p.o.) for a period of 30 days and isoproterenol(ISO) was injected on the 29th and 30th day.At the end of experiment i.e.on the 31st day electrocardiographic,hemodynamic,biochemical and apoptotic changes were monitored from control and experimental groups.Results:ISO injected ruts showed a significant alteration in electrocardiograph pattern and hemodynamic changes(i.e. systolic,diastolic and mean arterial pressure).It also showed significant increase in C-reactive protein,myeloperoxidase,nitrite levels and Caspase-3 protease activity.In addition,it also exhibited alteration in the levels of electrolytes(Na^+,K^+ and Ca^(2+),vitamin E,uric acid and serum protein.Cel electrophoresis of ISO injected rats showed increase in DNA fragmentation.Triphenyl tetrazolium chloride staining of the heart section shows increase area of infarction in ISO injected rats.Pre-co-treatment with lycopene significantly prevented the ISO induced ullerution in ECC, haemodynamic,biochemical and apoptotic changes.Conclusions:The present result shows that treatment of lycopene in ISO injected rats significantly attenuates induced myocardial infarction.

Nigella sativa protects against isoproterenol-induced myocardial infarction by alleviating oxidative stress,biochemical alterations and histological damage

Objective: To evaluate the cardioprotective effect of Nigella sativa L.(N.sativa) in isoproterenol-induced myocardial infarction(MI).Methods: Groups were treated with different doses of ethanol extract of N.sativa(EENS)and N.sativa oil alone and along with enalapril for 28 days.MI was induced by subcutaneous administration of isoproterenol(85 mg/kg) in two consecutive doses.Levels of cardiac biomarkers and antioxidant enzymes such as creatine kinase–N-acetyl-L-cysteine, lactate dehydrogenase, aspartate aminotransferase, malondialdehyde, superoxide dismutase, reduced glutathione and catalase were evaluated along with gross histopathological examination.Results: Isoproterenol(85 mg/kg) induced MI by causing the significant(P < 0.01)reduction in the activity of cardiac biomarkers(creatine kinase–N-acetyl-L-cysteine,lactate dehydrogenase, aspartate aminotransferase) and antioxidant markers(superoxide dismutase, catalase, glutathione) along with significant(P < 0.01) increase in the level of malondialdehyde.Furthermore, histopathological evaluation also confirmed the isoproterenol-induced MI.Pretreatment with EENS(800 mg/kg) and combination of EENS(800 mg/kg) with enalapril(1 mg/kg) significantly(P < 0.01) prevented the development of these alteration and restored activity of cardiac biomarkers as well as antioxidant markers almost near to normal levels.Histopathological evaluation of cardiac tissue further confirmed the restoration of biochemical activity.Conclusions: Experimental findings thus indicate that EENS(800 mg/kg) demonstrated cardioprotective effect against isoproterenol-induced MI by restoring cardiac biomarkers and antioxidant status.

Synthesis,isolation,identification and characterization of new process-related impurity in isoproterenol hydrochloride by HPLC,LC/ESI-MS and NMR

One unknown impurity （Imp-II） during the analysis of laboratory batches of isoproterenol hydrochloride was detected in the level ranging from 0.04% to 0.12% by high performance liquid chromatography with UV detection. The unknown impurity structure was proposed as 4-[2-（propan-2oylamino）ethyl]benzene-l,2-diol （Imp-II） using the liquid chromatography-mass spectrophotometry （LC-MS） analysis. Imp-II was isolated by semi-preparative liquid chromatography from the impurity-enriched reaction crude sample. Its proposed structure was confirmed by nuclear magnetic spectroscopy such as 1H, 13C, DEPT （1D NMR）, HSQC （2D NMR） and infrared spectroscopy （IR）, and retention time and purity with HPLC followed by the chemical synthesis. Due to less removable nature of Imp-II during the purification, the synthetic process was optimized proficiently to control the formation of Imp-II below to the limit 〈 0.12% in the course of reaction. The new chemical route was developed for the preparation of this impurity in required quantity with purity to use as reference standard. The most probable mechanism for the formation of Imp-II was discussed in details.

Raman and UV-Vis Spectroscopy Applied to the Analysis of Liver Tissues from Rats with Myocardial Ischemia Induced by Isoproterenol

The application of the laser Raman spectroscopic（LRS） technique for the analysis of liver tissues from rats with myocardial ischemia induced by isoproterenol（ISO） was described.Animal model of myocardial ischemia was established for rats induced by ISO.Rats were randomly divided into four groups as normal group and myocardial ischemia groups.We observed the successful myocardial ischemia model via serum enzymes levels and hematoxylin-eosin（HE） staining,and detected the liver tissue of the rats from normal group and liver tissue of the rats from myocardial ischemia groups via UV-Vis spectroscopy（UV-Vis） and LRS,and the changes of the absorbance spectra were compared in the above four different groups.The results show that ISO can induce rat myocardial ischemia successfully.The spectrum of normal liver tissue supernatant exhibits a strong absorption band at 968 nm,but no absorption band appears in the spectra of liver tissue supernatant solutions from the rats with myocardial ischemia induction after 2,12 and 72 h presented at 968 nm.LRS results show that Raman intensities of the precipitates suffered from ISO-treatment after 2,12 and 72 h were obviously increased compared with that of the precipitate of the liver tissue of the normal rats suffered from 0.9 g/L normal saline（NS） treatment.These results indicate that LRS and UV-Vis can be harmless,nondestructive,rapid and effective methods for analyzing different pathological specimens of liver tissue from myocardial ischemia rats.

Protective effect of salvianolic acid A against isoproterenol-induced myocardial infarction in mice

OBJECTIVE To investigate the protective effect of salvianolic acid A(Sal A)on isoproterenol-induced myocardial infarction in mice and its possible mechanisms.METHODS The mice were subcutaneously injected with isopropranol(ISO 8mg·kg-1)to induce myocardial infarction and evaluated the myocardial protective effect of Sal A from mortality rate,electrocardiogram(ECG),heart function,myocardial infarction index,serum myocardial enzymes and explored its possible mechanisms from inflammatory,antioxidant and cells apoptosis.RESULTS Sal A can dose-dependently enhanced the heart function of myocardial infarction mice,reduced the heart index,inhibited the myocardial enzyme leakage,showed obvious myocardial protection effects.ELISA results showed that Sal A can reduce the expression of myocardial inflammatory cytokines such as IL-6,TNF-α.Western blotting confirmed that Sal A can increase the expression of anti-apoptotic proteins Bcl-2,reduce the expression of apoptosis protein Bax,and raise the phosphorylation level of PI3K and Akt.CONCLUSION Sal A have displayed significant protective effect against isoproterenol-induced myocardial infarction and its mechanism may be related to increasing of PI3K/Akt signal pathway and inhibition of cell apoptosis and inflammatory reaction.

Salvianolic acid A attenuates isoproterenol-induced myocardial infarction in mice through PI3K/Akt signal pathway

OBJECTIVE To investigate the protective effect of salvianolic acid A(Sal A)on isoproterenol-induced myocardial infarction in mice and its possible mechanisms.METHODS The mice were subcutaneously injected with isopropranol(ISO 8 mg·kg-1)to induce myocardial infarction and evaluated the myocardial protective effect of Sal A from mortality rate,electrocardiogram(ECG),heart function,myocardial infarction index,serum myocardial enzymes and explored its possible mechanisms from inflammatory,antioxidant and cells apoptosis.RESULTS Sal A can dose-dependently enhanced the heart function of myocardial infarction mice,reduced the heart index,inhibited the myocardial enzyme leakage,showed obvious myocardial protection effects.ELISA results showed that Sal A can reduce the expression of myocardial inflammatory cytokines such as IL-6,TNF-α.Western blotting confirmed that Sal A can increase the expression of anti-apoptotic proteins Bcl-2,reduce the expression of apoptosis protein Bax,and raise the phosphorylation level of PI3K and Akt.CONCLUSION Sal A have displayed significant protective effect against isoproterenol-induced myocardial infarction and its mechanism may be related to increasing of PI3K/Akt signal pathway and inhibition of cell apoptosis and inflammatory reaction.

Effects of Isoproterenol and Metoprolol on the Suppression of Propafenone on with Supraventricular Tachycardia

This study was to determine whether isoproterenol (Iso) reverses the effects of propafenone(Pro) on the induction of supraventricular tarhycardia and whether the revergal during electrophysiologicstudy (EPS) is predictive of clinical recurrences of SVT during long-term treatment with Pro.Thirtypatients with inducible sustained SVT at baseline state were studied. Iso infusion at a rate necessary toachieve a 20%-40% increase in heart rate completely (16/28 cases,57%) or partially (5/28 case, 18%)revereed Pro's suppressant effects on the induction of SVT.There were clinical recurrcnces of SVT in fiveof 16 patients (31%) treated on a long-term basis (mean 4.5±3.6 months) with Pro,Iso completelyreveroed Pro's supprosant effect on the induction of SVT in four of these five patients (80%).These fivepatients then were treated with Pro and metoprolol and no further clincal recnrrences of SVT.These resultssuggested that reveroal by Iso ofpro's suppresaant effects on the induction of SVT may identify patients whoare likely to experience clinical recurrence of SVT and these patients may benefit from treatment with aB-blocker during longterm therapy with Pro.

Determination of isoproterenol in pharmaceutical and biological samples using a pyrogallol red multiwalled carbon nanotube paste electrode as a sensor

Isoproterenol （ISPR） is an important catecholamine‐based drug that is widely used in the treatment of heart disease. However, overdose of this drug is very dangerous to the human body. In this study, a new sensor based on a pyrogallol red modified‐multiwalled carbon nanotube paste electrode （PGRMMWCNTPE） was prepared and used for high sensitivity determination of ISPR in aqueous solution. Electrocatalytic oxidation of ISPR at the PGRMMWCNTPE was investigated by chronoam‐perometry, cyclic voltammetry, and square‐wave voltammetry. The values of the catalytic rate con‐stant, electron transfer coefficient, and diffusion coefficient for ISPR oxidation were then calculated using voltammetric data. A linear calibration curve was constructed for ISPR concentration in the range 0.8–570μmol/L with a detection limit of 0.47μmol/L ISPR. The sensor was then applied to the determination of ISPR in urine and drug samples with satisfactory results.

Ion mechanism of isoproterenol on delayed afterdepolarization and triggered activity in the infarcted ventricle

Objectives This study aimed at investigating the cellular mechanism of isoproterenol （ISO） on delayed afterdepolarizations （DADs） and triggered activity （TA） of the noninfarcted myocardium in the myocardial infarcted rabbit model.Methods Rabbits with the left anterior descending coronary artery occlusion were prepared and recovered for 8 wk （healed myocardial infarction, HMI）. Myocytes were isolated from regions of the noninfarcted left ventricular free wall. ISO was added to cellular surface by perfusion way. Action potentials and ion currents were recorded with whole-cell patch clamp. Results The results showed that treatment with ISO induced more DADs and TA events in HMI myocytes. Iti and IC,_L of myocytes treated with ISO were increased significantly compared with HMI cells, which contributed to DADs-related triggered arrhythmia. Conclusions The results suggested that more arrhythmia events of DADs and TA developed in myocytes with ISO treatment. The underlying mechanism was associated with the augment of I6 and calcium influxing

Assessment of mitral valve reserve capacity before and after percutaneous balloon valvuloplasty with isoproterenol stress echocardiography

Objective: To explore whether successful valvuloplasty increases mitral valve reserve capacity in patients with mitral stenosis. Methods: Thirty-eight patients with pure rheumatic mitral stenosis underwent isoproterenol stress echocardiography before and after successful percutaneous balloon valvuloplasty. The mitral valve area (by direct planimetry of two-dimensional echocardiography), mean transmitral pressure gradient (by continuous-wave Doppler echocardiography), and cardiac output (by M-mode echocardiography) were measured at rest and under isoproterenol infusion to achieve heart rate of different stages. Results:Between the measurements before and after valvuloplasty, significant differences were observed in the mitral valve area (0. 91±0. 28 vs 1. 87±0. 23 cm2, P<0. 01), mean transmitral pressure gradient (12. 5±6. 3 vs 3. 9±1. 9 mmHg, P<0. 01) and cardiac output (3. 93±1. 44 vs 4. 73±1. 01 L/min, P<0. 05) at rest. Before valvuloplasty, the mean transmitral pressure gradient increased significantly (P<0. 01) as heart rate increased, but there were no significant differences in the measurements of mitral valve area and cardiac output (both P>0. 05). In contrast, there was a significant increase after valvuloplasty in the mean transmitral pressure gradient (P<0. 01), but both mitral valve area and cardiac output further increased (both P< 0. 01) as heart rate increased. Moreover, valvuloplasty decreased the mean transmitral pressure gradient at peak heart rate from 23. 0±4. 5 to 7. 75±2. 30 mmHg (F<0. 01) under submaximal stress. Conclusion: Successful percutaneous balloon valvuloplasty soon causes a significant increase of mitral valve reserve capacity in patients with mitral stenosis, which is conspicuously manifested under condition of hemodynamic stress. Stress echocardiography provides a safe, feasible and non-invasive means of assessing the reserve capacity.

Dalbergia odorifera Essential Oil Protects against Myocardial Ischemia through Upregulating Nrf2 and Inhibiting Caspase Signaling Pathways in Isoproterenol-Induced Rats

Objective:Dalbergia odorifera has long been used as a Chinese herbal medicine for the treatment of cardiovascular and cerebrovascular diseases.This study aimed to determine the potential myocardial protective effect and possible mechanism of action of D.odor ife ra essential oil(DOEO).Materials and Methods:The essential oil of D.odorifera was extracted by hydrodistillation.The cardioprotective effects of DOEO were examined by histopathological observation,myocardial enzyme detection,peroxidation,anti-oxidant level detection,and related protein expression.The compounds in the blood were identified by gas chromatography-mass spectrometry.Results:These results showed that DOEO had significant myocardial cell protection,with IC50 values ranging from 17.64 to 24.78μg/mL in vitro.Compared to the myocardial ischemia group,the DOEO pretreatment groups had lower levels of myocardial injury,creatinine kinase,lactate dehydrogenase,alanine transaminase,aspartate transaminase,hydrogen peroxide,and nitric oxide,and higher levels of glutathione and superoxide dismutase.In addition,DOEO pretreatment significantly increased Na+-K+-ATPase and Ca2+-ATPase levels.Moreove r,immunohistochemical e xperiments showed that DOEO remarkably increased the protein levels of NF-E2-related nuclear factor 2(Nrf2)and heme oxygenase-1(HO-1)and reduced the expression of apoptotic caspases,including caspase 3 and caspase 9.The main components of the blood were transnerolidol and nerolidol oxide.Overall,the study showed that DOEO displayed myocardial protection by upregulating the NF-E2-related nuclear factor-antioxidant response element(Nrf2-ARE)and caspase pathways.DOEO has a therapeutic effect on MI by inhibiting the oxidant and apoptotic effects.Conclusions:D.odorifera may be a potential candidate drug for treating myocardial ischemic injury.

“心痛三两三”方对异丙肾上腺素引起的斑马鱼心肌缺血的作用

目的:研究“心痛三两三”方对异丙肾上腺素引起的斑马鱼心肌缺血的作用。方法:用“心痛三两三”方9.4、18.75、37.5、75、150和300μL/mL浓度干预受精后2~3 d野生型AB品系斑马鱼,根据斑马鱼的毒性表型和死亡情况确定“心痛三两三”方的最大耐受浓度,从而筛选出本研究的给药剂量。实验设“心痛三两三”方高、中、低剂量组,浓度分别为75.0、25,0、8.3μL/mL,阳性对照丹参滴丸组浓度为500μg/mL,正常对照组和模型对照组,每组30尾置于六孔板中,各组均置于28℃培养箱中培养4 h后,用50 mg/mL盐酸异丙肾上腺素诱导60 min建立斑马鱼心肌缺血模型。共同处理结束后,用吖啶橙法染色分析斑马鱼心脏部位凋亡细胞荧光强度;心跳血流分析软件录制斑马鱼血流视频,分析斑马鱼心输出量和血流速度。结果:与模型对照组比较,“心痛三两三”方中、高剂量组斑马鱼心脏部位凋亡细胞荧光强度显著降低(P<0.05,P<0.01),其凋亡改善率分别为34%和54%。“心痛三两三”方低、中、高剂量组斑马鱼心输出量和血流速度明显提高(P<0.01),其改善率分别为52%、93%、62%和29%、53%、32%。结论:“心痛三两三”方对异丙肾上腺素诱导的斑马鱼心肌缺血具有明显改善作用,与改善心肌细胞凋亡有关。

土茯苓总黄酮改善ISO诱导的小鼠心肌肥大和心脏炎症的预防作用及机制

目的研究土茯苓总黄酮(Smilax glabra flavonoids,SGF)对异丙肾上腺素(isoproterenol,ISO)诱导的小鼠心肌肥大和心脏炎症的作用及机制。方法C57/6J小鼠随机分为正常组、ISO模型组(1.25 mg/(kg·d))、SGF低剂量组(50 mg/(kg·d))、SGF高剂量组(100 mg/(kg·d))。SGF低剂量组和SGF高剂量组均在造模前预防给药7 d,之后各组进行ISO皮下注射,连续注射7 d后进行超声心动图测定;眼眶取血分离血清,检测血清中N端脑钠肽前体(N-terminal brain natriuretic peptide precursor,NT-proBNP)及炎症因子白细胞介素-1β(interleukin-1 beta,IL-1β)、肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、白介素6(interleukin-6,IL-6)含量;收集心肌标本,观察心肌组织的病理学改变,二氢乙锭(dihydroethidium,DHE)染色法检测心肌活性氧(reactive oxygen species,ROS)水平,检测心脏相关肥大基因mRNA水平变化以及NOD样受体热蛋白结构域蛋白3/半胱天冬酶-1/白介素18(NOD-like receptor thermal protein domain associated protein 3/cysteinyl aspartate specific proteinase-1/interleukin-18,NLRP3/Caspase-1/IL-18)炎症级联通路上关键因子蛋白水平表达的变化。结果SGF预防给药可降低超声心动图中的左室舒张末期室间隔厚度(left ventricular end-diastolic inter ventricular septal thickness,IVSd)、左室收缩末期室间隔厚度(left ventricular end-systolic interventricular septal thickness,IVSs)和射血分数(ejection fraction,EF),提高左室舒张末期内径(left ventricular end-diastolic diameter,LVIDd)、左室收缩末期内径(left ventricular end-systolic diameter,LVIDs)和左心室收缩末期容积(left ventricular end systolic volume,LVESV),降低血中IL-1β、IL-6、TNF-α和NT-proBNP含量,抑制心脏相关肥大基因心房钠尿肽(atrial natriuretic peptide,ANP)、脑钠肽(brain natriuretic peptide,BNP)、β-肌球蛋白重链(beta-myosin heavy chain,β-MHC)mRNA表达水平上调,抑制心肌ROS水平增加,下调NLRP3/Caspase-1/IL-18炎症级联通路上关键因子NLRP3、Caspase-1(p20)和IL-18的蛋白表达,改善心肌细胞肥大和排列紊乱的情况,减少心肌纤维外的成纤维细胞增多,减轻炎症细胞浸润和心肌组织纤维化情况。结论SGF可改善ISO诱导的小鼠心肌肥大和心脏炎症,可能通过NLRP3/Caspase-1/IL-18炎症级联通路起作用。

肢体导联与胸导联心电图对异丙肾上腺素诱导大鼠心肌梗死的诊断价值

目的 分析注射异丙肾上腺素(isoproterenol, ISO)法建立的大鼠心肌梗死模型各导联的心电图表现,探讨适用于该模型的判断心肌梗死是否形成的观测导联。方法 给20只大鼠皮下注射ISO,间隔24 h后再次给药,每24 h内各记录一次肢体、胸导联心电图,测量除aVR导联以外的各导联J点的偏移值,并与各自导联用药前及用药后比较。48 h后处死大鼠,并取心脏做病理检查。结果 第2天用药前V_(2)导联J点抬高较Ⅱ、Ⅲ、aVF导联明显(P<0.01),Ⅱ、Ⅲ、aVF导联两两比较差异无统计学意义(P>0.05)。结论 ISO法建立大鼠心肌梗死模型的梗死区域较分散,多个导联可出现J点抬高,其中以V_(2)导联最为明显。实验中可选择上述导联之一予以观测,亦可采用肢体、胸导联同步监测。

Effect of acupuncture at Neiguan (PC 6) on cardiac function using echocardiography in myocardial ischemia rats induced by isoproterenol

OBJECTIVE: To investigate the effect of acupuncture at Neiguan(PC 6) on cardiac function using echocardiography in rat models of myocardial ischemia(MI) induced by isoproterenol(ISO).METHODS: Twenty-seven Sprague-Dawley rats were randomly assigned to normal, model, and acupuncture groups. The model and acupuncture groups were given injections of ISO(85 mg/kg) to establish the MI model. After model establishment,the acupuncture group was treated with acupuncture at Neiguan(PC 6) for 30 min. Echocardiography was used to monitor diastolic and systolic function for 30 min starting from the time after the acupuncture needles were removed. Changes in the length of left ventricular internal diameter at end-diastole(LVIDd), length of left ventricular internal diameter at end-systole(LVIDs), the ratio of mitral peak velocity at early diastole and atrial contraction(E/A), ejection fraction(EF), fractional shortening(FS), and stroke volume(SV) were measured.RESULTS: Compared with the model group at 0and 15 min after needles were removed, the means of LVIDd and LVIDs were significantly lower(P <0.01) and E/A, EF, FS, and SV significantly higher(P < 0.01) in the acupuncture group. In the acupuncture group, the means of LVIDd and LVIDs15 min after the needles were removed were significantly higher(P < 0.01) than those at 0 min. The means of E/A, EF, FS, and SV significantly decreased(P < 0.01) from 0 to 15 min in the acupuncture group.CONCLUSION: These findings indicate that acupuncture at Neiguan(PC 6) can affect cardiac function by increasing left ventricular diastolic and systolic function in MI rat models, but the effect only lasts for 15 min.