[Adverse cardiovascular effects of antiretrovirals in female mice during gestation].

Objective: To evaluate the effects of antiretrovirals on cardiovascular function and some biochemical indexes in gestational female rats. Methods: Nineteen 9-week-old female and six 10-week-old male SD rats were divided into normal control group (CON) and highly active antiretroviral therapy group (HARRT), 9/10 female rats and 3 male rats were combined into one cage, totally 2 cages. Female rats in CON group were intragastrically given with normal saline (NS, 10 ml/kg) every morning and evening, while female rats in HARRT group were treated with equal volume antiretrovirals (AZT 31.25 mg/kg + 3TC 15.63 mg/kg + LPV/r (41.67/10.42) mg/kg) for 3 months. The body weight and survival rate of female rats were recorded. Echocardiography and multichannel physiological recorder were used to detect arterial blood pressure and cardiac hemodynamic parameters. The levels of blood glucose, blood lipids, myocardial enzymes and liver enzymes were detected by corresponding kits. Myocardial collagen fibers were observed by Masson staining and the ultrastructure of myocardial cells were observed by transmission electron microscopy. Results: All female rats in CON group survived (9/9), while only 6 rats in HARRT group survived (6/10). Compared with CON group, the body weight of female rats in HAART group was decreased significantly(P＜0.01); the levels of left ventricular end diastolic diameter (LVDd), interventricular septal thickness (IVST), thickness of left ventricular posterior wall (LVPWT) , left atrial diameter (LAD) and arterial diastolic pressure were increased significantly (P＜0.05); the level of LVP+dP/dtmax was decreased (P＜0.01). The levels of triglyceride, creatine kinase, and glutamic oxaloacetic transaminase were decreased (P＜0.05 or P＜0.01), while the level of glucose was increased (P＜0.05). The collagen fibers were increased in myocardial tissue, and ultrastructure of myocardial cells was abnormal. Conclusion: Antiretrovirals during gestation can cause cardiovascular diseases in female rats.

R5 HIV-1 gp120 Activates p38 MAPK to Induce Rat Cardiomyocyte Injury by the CCR5 Coreceptor.

BACKGROUND: Effective antiretroviral therapy extends the survival of patients with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome, but these patients remain at higher risk for heart diseases compared with the general population. Previous studies have suggested that HIV-1 glycoprotein 120 (gp120) may be associated with heart disease. However, the underlying mechanisms by which HIV-1 gp120-mediated myocardial injury occurs remain unknown. OBJECTIVE: The current study aimed to uncover the mechanism of C-C chemokine receptor 5 (CCR5) coreceptor (R5) HIV-1 gp120-induced myocardial injury. METHODS: Morphology analysis, determination of the percentage of cell apoptosis, as well as lactate dehydrogenase (LDH) and creatine kinase (CK) assays were used to analyze whether R5 HIV-1 gp120 induced myocardial cell injury. We analyzed the phosphorylation of p38 mitogen-activated protein kinase (MAPK) with the CCR5 antagonist D-Ala-peptide T-amide (DAPTA) and NMDA receptor antagonist MK801, detected LDH and CK assays with p38 MAPK antagonist SB203580 (SB), and detected the percentage of cell apoptosis and death with DAPTA to investigate the mechanism of R5 HIV-1 gp120-induced myocardial cell injury. RESULTS: R5 HIV-1 gp120 damaged myocardial cells and induced p38 MAPK phosphorylation. SB blocked R5 HIV-1 gp120-induced myocardial cell injury. DAPTA blocked R5 HIV-1 gp120-mediated p38 MAPK phosphorylation, while MK801 did not. DAPTA inhibited R5 HIV-1 gp120-induced myocardial cell injury. CONCLUSION: Our data indicate that R5 HIV-1 gp120 activated p38 MAPK to trigger myocardial cell injury by the CCR5 coreceptor.

Sodium Ferulate Prevents Daunorubicin--Induced Apoptosis in H9c2 Cells via Inhibition of the ERKs Pathway.

BACKGROUND: Daunorubicin (DNR)-induced cardiotoxicity, which is closely associated with cardiomyocyte apoptosis, limits the drug's clinical application. The activation of the extracellular regulated protein kinases (ERKs) pathway is responsible for the pro-apoptosis effect of DNR Sodium ferulate (SF) has recently been found to attenuate both DNR-induced cardiotoxicity and mitochondrial apoptosis in juvenile rats. Nonetheless, the precise mechanism underlying SF-induced cardio-protection remains unclear. METHODS: The DNR-injured H9c2 cell model was prepared by incubating the cells in 1 µM DNR for 24 h. Amounts of 15.6, 31.3 or 62.5 µM SF were simultaneously added to the cells. The effect of SF on the cytotoxic and apoptotic parameters of the cells was studied by monitoring apoptosis regulation via the ERKs pathway. RESULTS: SF attenuated DNR-induced cell death (particularly apoptotic death), cTnI and ß-tubulin degradation, and cellular morphological changes. SF reduced mitochondrial membrane potential depolarization, cytochrome c leakage, and caspase-9 and caspase-3 activation. SF also decreased ERK1/2, phospho-ERK1/2, p53 and Bax expression and increased Bcl-2 expression. These effects were similar to the results observed when using the pharmacological ERKs phosphorylation inhibitor, AZD6244. CONCLUSION: We determined that SF protects H9c2 cells from DNR-induced apoptosis through a mechanism that involves the interruption of the ERKs signaling pathway.

[Sodium ferulate protects against daunorubicin-induced cardiotoxicity in juvenile rats].

OBJECTIVE: To investigate the protect effects of sodium ferulate (SF) on the daunormbicin(DNR-induced cardiotoxicity in juvenile rats. METHODS: Forty male juvenile SD rats were randomly divided into control group (Control), daunorubicin group (DNR), sodium ferudate treatment group (DNR + SF), sodium ferudate group (SF) (n = 10) . Juvenile rats were intraperitoneally treated with DNR (2.5 mg/kg every week for a cumulative dose of 10 mg/kg) preparation immature myocardial injury model in presence with SF (60 mg/kg) oral treat- ment for 25 days. The left ventricular pressure and its response to isoproterenol were measured using left ventricular catheter. Rat myocardium myocardial pathology specimens and ultrastructure changes were also observed. The expression of cardiac Troponin I (cTNI) was detected by Western blot and RT-PCR. Results: SF treatment could inhibit the decreasing of heart rates induced by DNR damage (P < 0.05); it could increase the left ventrivular end diastolic pressure(LVEDP), heart rate, the maximal left ventrivular systolic speed(LVP + dp/dtmax) and the maximal left ventrivular diastolic speed (LVP-dp/dtmax) responding to isoproterenol stimulation(P < 0.01); SF also could improve the myocardial ultrastructure injuries and inhibit the decreasing of cTNI expression caused by DNR damages (P < 0.05). CONCLUSION: SF treatment could alleviate the decreasing of cardiac reservation induced by DNR damages in juvenile rats, which might be related to its reversing the effects on the cardiac systolic and diastolic function injuries and its inhibiting effects on the decreasing of cTNI expression caused by DNR. The mechanism of SF preventing daunorubicin-induced cardiotoxicity in juvenile rats is relevant to inhabited cardiac Troponin I expression.

Sodium ferulate protects against daunorubicin-induced cardiotoxicity by inhibition of mitochondrial apoptosis in juvenile rats.

Daunorubicin (DNR) is a widely used chemotherapeutic agent; however, its clinical use is limited because of its cardiotoxicity. This study was aimed to investigate the protective effect of sodium ferulate (SF), an effective component from traditional Chinese herbs, against DNR-induced cardiotoxicity in juvenile rats. DNR was administered intraperitoneally to rats at the dosage of 2.5 mg·kg(-1)·wk(-1) for 5 consecutive weeks (cumulative dose of 12.5 mg/kg) or in combination with intraperitoneal injection of SF at 50 mg·kg(-1)·d(-1) over a period of 30 days. The animals were killed 6 days after the last injection of DNR. SF significantly ameliorated the DNR-induced cardiac dysfunction, structural damage of the myocardium, and release of lactate dehydrogenase and creatine kinase. Treatment with SF also reversed DNR-induced oxidative stress as evidenced by a decrease in malondialdehyde levels with a concomitant increase in myocardical superoxide dismutase activities. Furthermore, SF afforded significant cardioprotection against DNR-induced apoptosis in vivo and effectively suppressed the complex mitochondrion-dependent apoptotic signaling triggered by DNR. This study indicates that SF may improve cardiac function by inhibition of oxidative stress and apoptosis, thus providing a beneficial effect on the prevention of DNR-induced cardiotoxicity.

[The application of isoprenaline provocation test on rat model of alcoholic cardiomyopathy].

OBJECTIVE: To study a simple and reliable method to produce the rat model of alcoholic cardiomyopathy, evaluating the model with isoprenaline provocation test (IPT) and morphological indicators. METHODS: Adult male rats were intragastrically infused of wine (52% v/v) at 20 g/(kg x d) for 15 days with the general condition, the change of eating amount and weight being observed. The levels of mean left ventricle systolic pressure (mLVSP), mean left ventricle diastolic pressure (mLVDP), mean left ventricle pressure (mLVP), heart ratio (HR), maximal rise velocity of left ventricular pressure (+ dp/dtmax), maximal fall velocity of left ventricular pressure (- dp/dtmax) and the reaction of isoprenaline were examined by left ventricular cannulation, and the morphological change was observed with optical microscope and transmission electron microscopy. RESULTS: Both diastolic and systolic function of the model rats was lower than that of the control group as well as the cardiac energy reserve induced by IPT. Pathological observation demonstrated myocardial hypertrophy, myocardiocyte necrosis and infiltration of inflammatory cells. The transmission electron microscopy showed that mitochondria became enlarged or crimpled with fused or disappeared cristae and myofibrils dissolved and fractured. CONCLUSION: The adult male SD model rats exhibit diabetic cardiomyopathy by intragastric infusion of wine (52% v/v) at 20 g/(kg x d) for 15 days. IPT can induce the cardiac energy reserve and evaluate that accurately, displaying the hidden heart dysfunction.

[Study on the effect of cardioplegia induced by kalium-verapamil-propranolol in different temperatures on the function of immature rat heart].

OBJECTIVE: To explore the appropriate temperature of the kalium-verapamil-propranolol (KVP) cardioplegia by observation of the effect on the function of the immature rat heart. METHODS: Isolated hearts from immature rats were perfused by Langendorff method, and assigned to 1 of the following 5 groups (n = 6-8): control, continuously perfused for 170 min at 36 degrees C, normal temperature, normal perfused for 20 min, changed to perfuse with KVP for 3 min then no perfusion 87 min (ischemia 90 min), followed by 60 min reperfusion. 3 groups of low temperature, perfused for 15 min, cool down to 32 degrees C, 28 degrees C and 24 degrees C especially in 5 min, and at 20th min. heart rate (b/min), tension (g), contraction force (g), peak systolic velocity (dT/dt(max)), peak diastole velocity (dT/dt(max)), coronary flow (Drop/min) were monitored during the whole perfusion. RESULTS: Compared to control group, the heart tension increased after 50 min KVP ischemia. The protection of KVP in normal temperature (36 degrees C) was better than lower temperature (32 degrees C, 28 degrees C, 24 degrees C) such as reducing bad contraction, keeping normal myocardium tension,recovering heart rate, recovering the fuction of contraction force and protecting the coronary flow. CONCLUSION: The KVP cardioplegia in normal temperature has the better effect than that in hypothermia to protect the immature heart.

Dilated cardiomyopathy in transgenic mice expressing HIV Tat.

Mechanisms responsible for HIV cardiomyopathy are unknown, but may include direct effects of HIV proteins on the heart. Transgenic mice (TG) expressing HIV Tat protein targeted to the myocardium, +/- Tat TG, have revealed anatomical and biochemical defects in the heart. The present studies were conducted to clarify the effect of Tat on cardiac function. In vivo hemodynamics was measured in awake mice after inserting a catheter tip in the left ventricle under general anesthesia. Under the age of 3 months, the heart rate (HR) was significantly lower in TG (591 +/- 47 vs. 716 +/- 45 bpm, TG versus FVB control (FVB), respectively (P < 0.05; n = 8-12). Other hemodynamic indexes, including left ventricular systolic pressure (LVSP), positive and negative dp/dt (mmHg/s), and left ventricular end diastolic pressure (LVEDP) remained indistinguishable from FVB. At 6 months, however, ventricular dysfunction was evident in TG (HR = 580 +/- 47 vs. 673 +/- 25 bpm, TG versus FVB, P < 0.05); LVSP (132 +/- 6 vs. 147 +/- 6 mmHg, TG versus FVB; P < 0.05); LVEDP (15 +/- 4 vs. 8 +/- 6 mmHg, TG vs. FVB, P < 0.05); +dp/dt = 8872 +/- 331 vs. 10026 +/- 796 mmHg/s TG versus FVB, P < 0.01) and -dp/dt (7403 +/- 432 vs. 8835 +/- 368 mmHg/s, TG versus FVB, P < 0.01; n = 8-12, in each group). The change in percentage of fractional shortening in response to isoproterenol was also significantly reduced in cardiac myocytes isolated from TG versus FVB (P < 0.05). Thus, targeted myocardial transgenic expression of HIV Tat in mice results in relative bradycardia, depression in systolic and diastolic functions in vivo, and blunted adrenergic responsiveness in vitro.

CXCR4 receptor antagonist blocks cardiac myocyte p38 MAP kinase phosphorylation by HIV gp120.

The prognosis for patients with human immunodeficiency virus (HIV) infection has improved remarkably as a result of effective antiretroviral therapy. This has resulted in an increased awareness of cardiac complications from HIV infection, including cardiomyopathy and overt heart failure. Mechanisms responsible for HIV cardiomyopathy and heart failure are unknown, but may include direct effects of HIV proteins on the heart. We have previously reported that the HIV envelope glycoprotein, gp120, has a p38 MAP kinase-dependent negative inotropic effect on adult rat ventricular myocytes (ARVM). This signaling pathway presumably results from the binding of gp120 to a specific receptor on the surface of cardiac myocytes. HIV gp120 has been shown to bind to CD4, CXCR4, and CCR5 receptors on lymphocytes and macrophages. Accordingly, we sought to determine if HIV gp120 regulated its negative inotropic effect through activation of one of these binding sites on cardiac myocytes. AMD3100, a highly selective CXCR4 receptor antagonist, reversed HIV gp120-induced negative inotropic effect on ARVM. AMD3100 also blocked HIV gp120 phosphorylation of both p38 MAP kinase and Troponin I. The binding of gp120 to the CXCR4 receptor on ARVM was confirmed by co-immunoprecipitation. We conclude that the negative inotropic effect of HIV gp120 is mediated by a novel signaling pathway that begins with binding to a cardiac myocyte CXCR4 receptor, followed by phosphorylation of both p38 MAP kinase and Troponin I.

[The effect of different dose of verapamil and propranolol in kalium cardioplegia on the function of immature rat heart].

AIM: To explore the appropriate dose of the verapamil and propranolol in kalium cardiaplegia (KVP) by observation of the effect on the function of ischemic immature rat heart and compared with ST. Thomas II cardiaplegia. METHODS: 48 isolated hearts from Sprague-Dawley rats of 60 to approximately 80 g body weight, 22 +/- 2 days, male or female are perfused by Langendorff method for 20 min, and assigned to 1 of the following 6 groups (n = 8): control (CON), continuously perfused for 150 min. Ischemia/reperfusion (I/R), perfused with Locke's solution without glucose and oxygen equilibration for 3 min then no perfusion 27 min, repeated 3 cycles (ischemia for 90 min), followed by reperfusion for 60 min. Ischemia protected with ST. Thomas II cardioplegia (ST), each 3 min perfusion with ST. Thomas II cardioplegia during ischemia. Ischemia protected with three dose KVP cardioplegia (L, M, and H), perfused with ST. Thomas II cardioplegia containing verapamil and propranolol (x 10(-7) mol L(-1)) respectively 2.0, 0.34 (L), 6.8, 1.1 (M), 20,3.4 (H) during each 3 min perfusion of ischemia. Heart rate (min (-1), tens on(g), contraction force(g), peak systolic velocity (g.s-1), peak diastole velocity (g.s-), coronary flow (ml x min(-1 ), re-beat time (s) were monitored during the ischemia/ reperfusion. RESULTS: Compared to CON group, heart tension was rose when ischemia for 40 min and kept higher and could not rebeat after reperfusion in I/R group, In ST group, heart tension was rose after ischemia for 60 min and could re-beat but the pulse was weaker. Compared with ST group, KVP decreased the ischemic cardiac tension in dose dependently and the re-beat was stronger in L, M, and H groups. While compared with CON group, in L group, heart tension was rose when ischemia for 60 min and the re-beat was weaker. In H group, the heart tension was maintained lower when ischemia for 40 min and the re-beat was delay and weaker. Only in M group, heart tension was maintained stable during ischemia for 90 min and re-beat was stronger after reperfusion. CONCLUSION: Kalium cardiaplegia containing verapamil 6.8 x 10(-7) mol x L(-1) and propranolol 1.1 x 10(-7) mol x L(-1) has the best effect to protect the immature heart from ischemic injury.

Inducible nitric oxide synthase attenuates adrenergic signaling in alcohol fed rats.

Chronic, excessive alcohol consumption is associated with myocardial dysfunction in humans. The molecular mechanisms and cellular signaling pathways contributing to this cardiac dysfunction remain largely unknown. This study examined the effects of chronic alcohol consumption on myocardial function and cardiac myocyte signaling pathways. Adult male rats were fed a commercially prepared diet containing either ethanol (13 g/kg/d) or isocaloric control diet for 1 month. In vivo hemodynamics were measured in awake rats after inserting a catheter tip in the left ventricle under general anesthesia. Ventricular dysfunction was evidenced in awake, alcohol-fed rats by increased left ventricular end diastolic pressure, decreased systolic developed left ventricular pressure, and decreases in both positive and negative dp/dt compared with controls. Cardiac myocytes isolated from alcohol-fed rats also demonstrated an attenuated response to the beta-adrenergic agonist, isoproterenol, compared to controls. This response was significantly reversed by the nitric oxide synthase (NOS) inhibitor, N-monomethyl-L-arginine (L-NMMA). Western analyses confirmed inducible nitric oxide synthase (iNOS) protein synthesis in cardiac myocytes isolated from alcohol fed rats. It is therefore concluded that chronic alcohol ingestion results in iNOS-mediated attenuation of adrenergic signaling and depression in both systolic and diastolic function in rats.