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Objective: To study the protective effect of the total flavones in Microcos paniculata (TFMP) on the acute myocardial ischemia (AMI) induced by isoprenaline (ISO) and its mechanism. Methods: The rats were ig administered with TFMP (8, 4, and 2 mg/kg) once daily for consecutive 5 d, and the AMI rat model was established by sc injection with ISO (2 mg/kg) 1 h after the last administration. The effects of TFMP on the electrocardiogram (ECG) at different time points and the myocardial tissue pathological histomorphology dying by hematoxylin were observed; The superoxide dismutase (SOD) and malondialdehyde (MDA) levels of myocardial tissue, glutathione peroxidase (GSH-Px), lactate dehydrogenase (LDH), and creatine kinase (CK) activities in serum were detected using biochemical method. Results: Compared with the model group, the high- and mid-doses (8 and 4 mg/kg) TFMP inhibited the J spot downward of ECG during myocardial ischemia (P < 0.05), especially after 10 min of ISO injection. The myocardial injury induced by ISO was aslo improved in these two groups, the levels of LDH and CK in serum (P < 0.05) and the content of MDA in myocardial homogenate (P < 0.01) were decreased, the activities of SOD (P < 0.01) and GSH-Px (P < 0.05, 0.001) in the myocardial homogenate were increased. Conclusion: The TFMP has the apparent protective effect on AMI injury, its mechanism may be related with improving the myocardial anti-oxidative ability and decreasing the oxidative stress reaction.
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Objective To observe the protective effect of magnesium gluconate on myocardial apoptosis by ischemia reperfusion injury in isolated rat hearts, and study the possible mechanism. Methods The hearts of 48 Sprague-Dawely rats were isolated, linked to Lange-ndorff perfusion apparatus, and randomly divided into 3 equal groups(n = 16 each) : Control group, ischemia/reperfusion (I/R) group and magnesium gheonate group. 8 rats in each group were perfused. Control group was pedused with modified KH buffer for 110min. I/B group was perfuesd with modified KH buffer for 20 min, then exposed to iscbemia for 30 min, and then reperfused with modified KH buffer for 60 min. Magnesium gheonate group was perfumed with modified KH buffer with magnesium gluconate for 20 min, then exposed to isohemia for 30 min and then reperfused with modified KH buffer with magnesium glueonate for 60 min. Lacate dehydrogenase (LDH) and ereatine kinase (CK) in the effluent liquid from the heart were measured after reperfusion. The concentration of Ca2+ and NO in the left ventricle were determined. The other 8 rats in each group were reperfused for 120 minutes as the method described before. After repeffusion, the myoeyte apoptosis was examined by Annexin-V-FITC/PI. After the two experiments the incidence of ventrieular arrhytlunias during reperfusion was assessed. Results Compared with I/R, magnesium glueonate decreased the incidence of ventricular an'hythmias(P <0. 01). The contents of CK and LDH in the effluent liquid from the heart in magnesium glueonate group was lower than that of I/R group (P <0. 01). The contents of Ca2+ and NO in the left ventricle in magnesium gluconate group was decreased than that of I/R group (P <0. 01). The index of myocyte apoptosis were significanfly lower in magnesium glueonate group than that of I/R group (apoptosis index :27.79±1.59 vs 33.61±2.10, P < 0. 01) . Conclusion Magnesium glueonate has protective effect on myocardial isohemia reperfusion injury in rats. The protective effect may be related to decreasing myocyte apoptosis by increasing the content of NO and relieving calcium overload.
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Objective To investigate the protective effects and molecular mechanism of peroxisome proliferate-activated receptor α(PPARα) activation on acute myocardial damage induced by isoproterenol (Iso) in rats. Methods Thirty male Wistar rats, weighting 160～180 g, were randomly divided into control group, Iso group, fenafibrate(FF) group(each n=10) according to physique quantity. Acute myocardial injury caused by Iso abdomen cavity injection induced ischemia was established and the protective effects of peroxisome proliferate-activated receptor α activation were accessed by the level of ereatine kinase(CK), lactic dehydrogenase(LDH) in serum as well as the activities of myoperoxidase(MPO) in myocardium, and the protein expressions of PPABα in myocardium by Western blot. Results The level of serum CK in control group, lso group and FF group, was (62.41±9.47),(101.71±11.05),(75.64±11.73)kU/L, respectively(F= 34.34, P<0.01). Whereas the level of serum CK in Iso group and FF group was higher than that in control group(P<0.01 or<0.05), the level of serum CK in FF group was lower than that in Iso group(P<0.01). The levels of LDH in these three groups were (5912.20±204.44), (6365.78±137.10), (6089.76±169.60) U/L, respectively(F= 17.54, P<0.01). Compared with the control group, the levels of LDH in Iso and Fir groups were significantly increased(P<0.01 or<0.05). But the level of LDH in FIr group was decreased compared with that in Iso group(P<0.01). The activities of myocardial MPO in these three groups were (1.95±0.10),(3.89±0.17),(2.49±0.19)U/g, espectively(F=391.68,P< 0.01). The activities of myocardial MPO in Iso and FF groups were higher than that in the control group (all P< 0.01), while the activities of myocardial MPO in FIr group were lower than that in lso group(P<0.01). The protein expressions of PPARα in myocardium of these three groups were 251.57±10.95,191.97±10.74,215.08±9.61, respectively(F=82.69, P<0.01). Conclusion PPARα activation by its actor FF can exert protective effects on the acute myocardial ischemia injury induced by lso in rats through inhibiting the release of inflammatory cell factors.
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Objecfive To investigate possibihty of monitoring myocardial isehemia by eontinuous EASI 12-lead ST-segment trend analysis during orthopaedic surgery and find its rules.Methods Three hundred and eleven consecutive patients who underwent orthopaedic surgery were monitored bv continuous EASI 12-lead ST-segment analysis during surgery.Results Among 311 patients 81 patients(26.0%) had myocardial ischemic events.The ischemie incidence of general anesthetics WaS signifieantly higher than local anesthetics(the spinal or epidural anesthetics and nerve-block anesthetics)(38.1%vs 23.0%.P＝ 0.01 5).During ischemie events the patients whose heart rate exceeded 90 beat per minute was 71.6% (58/81).Among the 177 isehemie events,the duration ofless than 5 minutes was 79.7%(141/177).ST-seg- ment deviation ofless than 0.15 mV was 71.2%(126/177).Conclusions During orthopaedic surgery EASt 12-lead electrocardiogram is the optimal approach for monitoring myocardial isehemia.The ischemic incidence of general anesthetics is significantly higher than local anesthetics.The myocardial ischemia events correlates with fast heart rate.The intraoperative myocardial ischemia events are more often transient.In most of these ischemic events ST-segment deviation is not very serious.
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Objecfive To observe the effect of high thoracic epidural block(HTEB)for preventing myocardial isehemia(MI)in pailents with coronary heart disease undergoing upper abdominal surgery. Methods Twenty patients undergoing upper abdominal surgery were randomly divided into two groups:M group(treated with HTEB,10 patients)was given both general anesthesia and HTEB and patient controlled epidural analgesia(PCEA)after operation and C group(without HTEB.10 patients)was given only general anesthesia and patient controlled intravenous analgesia(PCIA)after operation.The hemodynamies.ECG changes and serum troponin I and myoglobin and ereatine-kinase isozyme,the analgesia efficacy in M group were compared with those in C group.Results The hemodynamics in M group Was more stable than that in C group(P＜0.05).ComparedwithMgroup,thetotalnumberofST-segment depression attracheal extuba- tion moment and 10 hours after operation were significantly increased in C group(P＜0.05).The positive rates of Serum troponin I and creatine-kinase isozyme at 10 hours and 24 hours after operation in C group were much higherthan those in M group(P＜0.05).The an~tgesia effect in M group Was superiortothat in C group (P＜0.05)Conclusion The HTEB combined with general anesthesia may reduce mvocardial is- chemia in patients with coronary heart disease undergoing upper abdominal surgery.
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Objective To assess subendocardial systolic circumferential strain(CS),radial strain(RS)and radial displacement(RD)of left ventricle(LV)in short-axis view and LV global systolic function in open-chest canine model with acute myocardial ischemia using velocity vector imaging(VVI),and to establish their spatial correlationships.Methods Left anterior descending coronary artery(LAD)was ligated for 20 minutes to induce acute myocardial ischemia in 12 open-chest canine model.At baseline and 20 minutes after ischemia,two-dimensional dynamic gray-scale images of three standard left ventricular short-axis views at the levels of mitral annulus,papillary muscle and apex and the images of LV apical fourchamber and two-chamber view were acquired and transfefred to VVI workstation for off-line analysis.Peak systolic CS,RS and RD of eighteen segments and of three global short-axis sections of LV were measured at subendocardium.and LV ejection fraction(LVEF)and stroke volume(SV)were calculated using Simpson's method.The differences and correlationships were analyzed between them.Resuls Compared with the value at baseline,LVEF decreased significantly(P＜0.05)after ischemia.The peak systolic subendocardial CS,RS and RD of the affected segments,global CS,RD at papillary muscle and apex views and global RS at apex view were significantly lower than those at baseline after ischemia(P＜0.05).There was a good linear correlationship between the peak systolic CS and RD of 17 segments(except the middle segment of LV lateral wall after ischemia)and each global short-axis level before and after ischemia(r=0.662-0.995,P＜0.05,P＜0.01 or P＜0.001),The peak systolic RS of six segments and each global short-axis level(except the apex level at baseline)was correlated with RD(r=0.580-0.916,P＜0.05,P＜0.01 or P＜0.001);There was not statistical correlationship between global RDs and SV as well as LVEF.Conclusions Subendocardial circumferential strain and radial displacement may sensitively reflect the changes of regional and global myocardial systolic function induced by acute myocardial ischemia.The significant correlationship between subendocardial circumferential systolic strain and radial displacement might indicate that circumferential deformation of myocardium result in the changes of the radial displacement mainly.