【作者】 黄卓君；

【导师】 刘艳霞； 宋君秋； 吴艳娜；

【作者基本信息】 天津医科大学 ， 药理学， 2010， 硕士

【摘要】 目的：研究雷米普利与BQ-123单用及其联合应用对大鼠在体心肌缺血/再灌注(I/R)损伤的保护作用,并从氧化-抗氧化角度探讨其作用机制。方法：健康雄性Wistar大鼠72只,随机分为5组。假手术(sham)组、心肌缺血再灌注(I/R)组、雷米普利(RAM)组、BQ.-123(BQ)组、雷米普利与BQ-123联合给药(R&B)组。除sham组,其余各组均于冠状动脉左前降支(LAD)下穿线,行心肌30 mmin缺血/120 mmin再灌注(I/R)过程。其中RAM及R&B组在I/R前24 hr,用雷米普利1 mg/kg灌胃,其余各组以等体积生理盐水灌胃。I/R过程中,BQ及R&B组于LAD结扎前10 mmin至结扎30 mmin末,持续静脉输入BQ-123(10μg/kg/min) 2 ml,其余各组用等体积生理盐水持续静脉输入。sham组LAD穿线后不实施I/R过程。各组动物均连续监测心率(HR)、血压、标准Ⅱ导联心电图(ECG),记录缺血期室性心律失常(VA)的发生情况；用TTC染色法测定心肌梗死面积；用HE染色观察心肌形态学改变；用比色法检测血浆肌酸激酶(CK)及乳酸脱氢酶(LDH)活力,心肌组织中总-超氧化物歧化酶(T-SOD)、锰-超氧化物歧化酶(Mn-SOD)、过氧化氢酶(CAT)活力及丙二醛(MDA)含量。结果：1.雷米普利及BQ-123单用对大鼠在体心肌I/R损伤的影响I/R组,缺血期ST-段抬高幅度显著提高(P<0.001),室早(VPC)出现时间为5.11±0.78 min,持续时间为20.60±3.08 mmin；室速(VT)出现时间为6.05±1.65 min,持续时间为14.19±5.37 min；VPC、VT及室颤(VF)发生率均为100%；血浆CK及LDH活性均显著升高；梗死面积(IS)为82.51±8.66 mg,梗死区/危险区(IS/AAR)为38.76±4.63%；T-SOD活力为150.84±13.89 U/mgprot, Mn-SOD活力为52.68±8.82 U/mgprot, CAT活力为2.48±0.70 U/mgprot; MDA含量为2.77±0.18 nmol/mgprot。与I/R组比较,RAM及BQ组缺血期ST-段抬高幅度均显著降低(P<0.001),VPC(9.88±1.98；7.77±0.87 min)及VT(10.60±1.41；8.60±0.57 min)出现时间显著推迟,VPC(9.10±1.61；6.97±1.95 mmin)及VT(5.08±1.49；4.90±1.36 min)持续时间明显缩短,VPC、VT及VF发生率明显降低；血浆CK及LDH活性显著降低(P<0.001)；IS(46.99±9.94;,40.79±8.01 mg)及IS/AAR (22.68±3.24; 19.85±3.68%)显著缩小；心肌组织T-SOD(168.55±11.93；170.90±12.85 U/mgprot). Mn-SOD(78.11±8.78；80.02±9.72 U/mgprot)及CAT(3.80±0.66；3.83±0.39 U/mgprot)活力显著升高；心肌组织MDA含量(1.77±0.06；1.68±0.09nmol/mgprot)显著减少；心肌组织形态学损伤改变均明显减轻。2.雷米普利与BQ-123联合应用对大鼠在体心肌I/R损伤的影响与I/R组比较,R&B组ST-段抬高幅度显著降低(P<0.001),VPC(9.53±1.89mmin)及VT(8.80±1.39mmin)出现时间明显推迟,VPC(7.15±1.85 mmin)及VT(4.84±1.34 min)持续时间明显缩短；VT(44%)及VF(13%)发生率显著降低。血浆CK及LDH活性显著降低；IS(30.64±6.43 mg)及IS/AAR(15.62±5.00%)显著缩小；心肌组织T-SOD(192.12±10.70 U/mgprot)、Mn-SOD(102.85±11.73 U/m gprot)及CAT(4.36±0.60 U/mgprot)活力均显著升高;心肌组织MDA含量(1.51±0.08 nmol/mgprot)显著减少；心肌组织形态学损伤改变明显减轻。分别与RAM及BQ组单用比较,R&B组再灌注30 min及120 mmin时MAP明显升高；缺血30 min末CK活力及再灌注120 min末LDH活力均显著降低(P<0.001)；IS及IS/AAR比值均显著下降(P<0.001,P<0.05)；T-SOD(P<0.01)及Mn-SOD(P<0.001)均显著升高；MDA含量明显降低(P<0.001,P<0.01)。并且与BQ组比较,VPC出现时间明显推迟(P<0.01)；与RAM组比较,VPC持续时间明显缩短(P<0.05),但VT出现时间较早(P<0.05)。结论：1.雷米普利与BQ-123单用及合用对大鼠在体心肌I/R损伤具有保护作用。可减轻缺血期室性心律失常的发生程度,降低ST-段抬高幅度,减少心肌组织CK及LDH漏出,减轻I/R心肌细胞坏死,提高心肌组织抗氧化酶SOD及CAT活力,降低脂质过氧化代谢产物MDA含量,减轻I/R氧化损伤。2.雷米普利与BQ-123合用在减少心肌细胞CK及LDH漏出,减轻I/R心肌细胞坏死,提高心肌组织SOD活力、降低MDA含量方面优于两药各自单用。3.本实验首次探讨雷米普利与BQ-123合用对大鼠在体心肌I/R氧化损伤的保护作用。结果表明联合用药能有效保护缺血心肌组织,其机制之一是通过抗氧化损伤发挥的。更多还原

【Abstract】 Objective:To investigate the protection of ramipril, BQ-123 and their combination against myocardial ischemia/reperfusion (I/R) injury in vivo in anesthetized rats, and explore the role of myocardial oxidation-antioxidation system.Methods:Seventy-two healthy male Wistar rats were divided into 5 groups randomly:sham operated (sham) group, I/R group, ramipril (RAM) group, BQ-123 (BQ) group and ramipril and BQ-123 (R&B) group. All groups but not sham were subjected to 30 min ischemia/120 min reperfusion through ligation of the left anterior descending (LAD) coronary artery. Ramipril (1 mg/kg) was given orally to rats in RAM and R&B groups twenty four hours before I/R. The same volume of normal saline was given to rats in other groups. BQ-123 (10μg/kg/min) was infused intravenously from 10 min before ligation to the end of 30 min ischemia to rats in BQ and R&B groups during I/R procedue. The same volume of normal saline was given to other groups. Rats in sham group were not subjects to I/R procedure. Heart rate (HR), blood pressure and lead II electrocardiogram were monitored throughout the experiment and ventricular arrhythmia (VA) was recorded during ischemia. Myocardial infarct size was measured by TTC staining. Changes of myocardial morphology were observed after HE staining. Activity of plasma creatine kinase (CK) and lactate dehydrogenase (LDH), myocardial total superoxide dismutase (T-SOD), manganese superoxide dismutase (Mn-SOD) and catalase (CAT) and content of myocardial malondialdehyde (MDA) were detected by spectrophotometer.Results:1. Effects of ramipril and BQ-123 on myocardial I/R injury in ratsIn I/R group, the elevation of ST-segment was dramatically increased (P<0.001); onset of ventricular premature contraction (VPC) and ventricular tachycardia (VT) were 5.11±0.78 and 6.05±1.65 min, durations of them were 20.60±3.08 and 14.19±5.37 min; incidences of VPC, VT and ventricular fibrillation (VF) were 100% respectively; activity of plasma CK and LDH was significantly enhanced; infarct size/area at risk (IS/AAR) and IS were 38.76±4.63% and 82.51±8.66 mg; the activity of T-SOD, Mn-SOD and CAT was 150.84±13.89,52.68±8.82 and 2.48±0.70 U/mgprot respectively. MDA content was 2.77±0.18 nmol/mgprot.Compared with I/R group, the parameters in RAM and BQ groups were changed dramatically. The elevation of ST-segment was decreased (P<0.01), onset of VPC (9.88±1.98; 7.77±0.87) and VT (10.60±1.41; 8.60±0.57 min) were delayed, durations of VPC (9.10±1.61; 6.97±1.95 min) and VT (5.08±1.49; 4.90±1.36 min) were shortened, incidences of VPC, VT and VF were decreased. Activity of plasma CK and LDH was decreased. IS (46.99±9.94; 40.79±8.01 mg), IS/AAR (22.68±3.24; 19.85±3.68%), activity of T-SOD (168.55±11.93; 170.90±12.85 U/mgprot), Mn-SOD (78.11±8.78; 80.02±9.72 U/mgprot) and CAT (3.80±0.66; 3.83±0.39 U/mgprot) were increased respectively. MDA content (1.77±0.06; 1.68±0.09 nmol/mgprot) was decreased. The morphology of myocardium was improved.2. Effects of ramipril in combination with BQ-123 on myocardial I/R injuryCompared with I/R group, the R&B group was changed dramatically. The elevation of ST-segment was decreased (P<0.001); onset of VPC (9.53±1.89 min) and VT (8.80±1.39 min) were delayed, durations of VPC (7.15±1.85 min) and VT (4.84±1.34 min) were shortened; incidences of VT (44%) and VF (13%) were decreased; activity of plasma CK and LDH was significantly degraded; IS (30.64±6.43 mg) and IS/AAR (15.62±5.00%) were decreased; activity of T-SOD (192.12±10.70 U/mgprot), Mn-SOD (102.85±11.73 U/mgprot) and CAT (4.36±0.60 U/mgprot) was increased; MDA content (1.51±0.08 nmol/mgprot) was decreased. The morphology of myocardium was improved.Compared with RAM and BQ groups, the parameters of R&B group were changed dramatically. Mean arterial blood pressure (MAP) was increased in reperfusion 30 and 120min (P<0.001); activity of plasma CK in ischemia 30 min and LDH in reperfusion 120 min were both decreased (P<0.001); IS, IS/AAR and MDA content were decreased respectively. Activity of T-SOD and Mn-SOD was increased. The morphology of myocardial was improved. And compared with BQ group, onset of VPC was delayed (P<0.01); compared with RAM group, duration of VPC was shorten (P<0.05), onset of VT was earlier (P<0.05).Conclusions:1. The results documented that ramipril, BQ-123 and ramipril in combination with BQ-123 protected myocardium from I/R injury by decreasing the elevation of ischemia-induced VA and ST-segment, decreasing the release of CK and LDH and MDA content, increasing the activity of SOD and CAT.2. The protective effects on decreasing the release of CK and LDH, reducing necrosis of cardiomyocytes and increasing the activity of SOD and decreasing MDA content were better than using ramipril and BQ-123 alone.3. It was the first time to investigate the protective effects of ramipril in combination with BQ-123 on myocardial I/R oxidative injury in vivo. The results demonstrated that combined using these two agents may protect myocardium from I/R oxidative injury. The mechanism of protective effects was associated with the increase in antioxidative ability of myocardium.更多还原