Effect of pretreatment with coenzyme Q10 on isoproterenol-induced cardiotoxicity and cardiac hypertrophy in rats

Background: Coenzyme Q₁₀ (CoQ₁₀) is a lipid-soluble, vitamin-like substance found in the hydrophobic interior of the phospholipid bilayer of most cellular membranes. It appears to be involved in the coordinated regulation between oxidative stress and antioxidant capacity of heart tissue when the heart is subjected to oxidative stress in various pathogenic conditions.Objective: The objective of the present study was to investigate the effect of pretreatment with CoQ₁₀ (100 mg/kg) on isoproterenol (ISO)-induced cardiotoxicity and cardiac hypertrophy in rats.Methods: Albino male Wistar rats (250–300 g) were evenly divided by lottery method into 1 of the following 3 groups: the ISO group (olive oil 2 mL/kg orally for 18 days and ISO 1 mg/kg IP from days 9–18); the CoQ₁₀ + ISO group (CoQ₁₀ 100 mg/kg orally for 18 days and ISO 1 mg/kg IP from days 9–18); and the control group (olive oil 2 mL/kg orally for 18 days and water IP from days 9–18). Twenty-four hours after the last dose of water or ISO, the rats were anesthetized and an ECG was recorded. Blood was withdrawn by retro-orbital puncture for estimation of serum creatine kinase-MB (CK-MB) isoenzyme levels, lactate dehydrogenase (LDH) levels, and aspartate aminotransferase activities. The animals were euthanized using an overdose of ether. The hearts of 6 animals from each group were used for estimation of superoxide dismutase (SOD) activity, reduced glutathione (GSH) concentration, lipid peroxidation (LPO), malondialdehyde (MDA), and total protein concentration. Histopathology of the 2 remaining hearts in each group was carried out by a blinded technician.Results: A total of 24 rats (8 in each group) were used in this study; all rats survived to study end. Compared with the control group, the ISO-treated rats had a significant change in heart to body weight ratio (P < 0.001); significant changes in the endogenous antioxidants (ie, significantly higher myocardial MDA concentration [P < 0.001]; significantly lower myocardial GSH concentration [P < 0.001] and SOD activity [P < 0.01]); and significantly higher serum activities of marker enzymes (eg, CK-MB [P < 0.001] and LDH [P < 0.001]). Compared with the ISO group, the CoQ₁₀ + ISO group had a significant change in heart to body weight ratio (P < 0.001); significant changes in the endogenous antioxidants (ie, significantly lower MDA concentration [P < 0.05]; significantly higher myocardial GSH concentration [P < 0.001] and SOD activity [P < 0.05]); and significantly lower serum activities of marker enzymes (eg, CK-MB [P < 0.05] and LDH [P < 0.01]).Conclusion: Pretreatment with CoQ₁₀ (100 mg/kg) for 18 days was associated with moderate protection against ISO-induced cardiotoxicity and cardiac hypertrophy, and with lower myocardial injury by preserving endogenous antioxidants and reducing LPO in rat heart.     

伪人参皂苷GQ对异丙肾上腺素致大鼠急性心肌缺血的改善作用

目的：探讨新化合物伪人参皂苷GQ（PGQ）对异丙肾上腺素致急性心肌缺血大鼠心电图改变的保护作用。 方法：取Wistar大白鼠50只,随机分为生理盐水组、异搏定对照组及PGQ大、中、小3个剂量组,每组10只。舌下静脉注射预防给药PGQ 3.0、6.0和12.0 mg·kg^-1及异搏定0.2 mg·kg^-1,然后静脉注射2.0 mg·kg^-1异丙肾上腺素,测量心电图（ECG）标Ⅱ、胸Ⅰ(Ⅴ₁)和胸Ⅱ(Ⅴ₂)ST段的变化。 结果：标Ⅱ导联、Ⅴ₁导联、Ⅴ₂导联PGQ小、中、大剂量组ST段在各时间点抬高不明显,ST段抬高幅度低于盐水组（P<0.05,P<0.01,P<0.001）。结论：PGQ能明显降低异丙肾上腺素引起的ST段抬高,具有改善大鼠异丙肾上腺素 致急性心肌缺血心电图改变的作用。     

三氟拉嗪对异丙基肾上腺素性大鼠心肌线粒体损伤的影响

目的：研究三氟拉嗪（ＴＦＰ）对缺血心肌线粒体损伤的影响。方法：采用异丙基肾上腺素性心肌梗塞（ＩＳＰ－ＭＩ，皮下注射ＩＳＰ４０ｍｇ／ｋｇ）为模型，观察了ＴＦＰ对缺血心肌线粒体丙二醛（ＭＤＡ）、膜脂流动性、超氧化物歧化酶（ＳＯＤ）及血清磷酸肌酸激酶（ＣＰＫ）的影响。结果：ＴＦＰ明显减轻ＩＳＰ－ＭＩ后心肌线粒体膜脂流动性及ＳＯＤ活力的降低（Ｐ＜０．０５），并显著减少了血清ＣＰＫ及心肌线粒体ＭＤＡ的升高（Ｐ＜０．０５）。结论：ＴＦＰ能部分对抗ＩＳＰ所致的心肌线粒体损伤，其机制可能与抗脂质过氧化作用有关。     

Effects of ranitidine on contraction and action potentials in normal and potassium depolarized isolated papillary muscles of the guinea pig

The purpose of these experiments was to investigate the possible ionicbases for ranitidine (Ran) in isolated papillary muscles of the guinea pig.Ran,when the concentration was below 300μmol/L,had no influence on contraction ofnormal muscles and only above 0.3 mmol/L,it showed weak negative inotropic ef-fect.The contractile activity elicited by histamine in potassium depolarized mus-cles was depressed by Ran markedly and dose-dependently.The IC_(50) of Ran was0.273μmol/L.This depressant effect was reversed by an elevation of externalCa~(2+)concentration to 7.7mmol/L.The contraction induced by isoproterenol inpotassium depolarized preparations was not altered by Ran.Ran at theconcentrations of 1,10 and 100μmol/L failed to show influences on fast actionpotentials.However,Ran at 0.5μmol/L time-dependently inhibited slow action po-tentials.It is concluded that the ionic mechanism of Ran might be attributed toantagonized H_2 receptor of myocardium which in turn decreases Ca~(2+) inward cur-rent.     

Isoproterenol disperses distribution of NADPH oxidase,MMP-9, and pPKCε in the heart,which are mitigated by endothelin receptor antagonist CPU0213

Aim： Spatial dispersion of bioactive substances in the myocardium could serve as pathological basis for arrhythmogenesis and cardiac impairment by β-adrenoceptor stimulation. We hypothesized that dispersed NADPH oxidase, protein kinase Cε （PKCε）, early response gene （ERG）, and matrix metalloproteinase 9 （MMP-9） across the heart by isoproterenol （ISO） medication might be mediated by the endothelin （ET） - ROS pathway. We aimed to verify if ISO induced spatially heterogeneous distribution of pPKCε, NAPDH oxidase, MMP-9 and ERG could be mitigated by either an ET receptor antagonist CPU0213 or iNOS inhibitor aminoguanidine. Methods：Rats were treated with ISO （1 mg/kg sc） for 10 days, and drug interventions （mg/kg） either CPU0213 （30 sc） or aminoguanidine （100 ip） were administered on days 8-10. Expression of NADPH oxidase, MMP-9, ERG, and PKCε in the left and right ventricle （LV, RV） and septum （S） were measured separately. Results： Ventricular hypertrophy was found in the LV, S, and RV, in association with dispersed QTc and oxidative stress in ISO-treated rats. mRNA and protein expression of MMP-9, PKCε, NADPH oxidase and ERG in the LV, S, and RV were obviously dispersed, with augmented expression mainly in the LV and S. Dispersed parameters were re-harmonized by either CPU0213, or aminoguanidine. Conclusion： We found at the first time that ISO-induced dispersed distribution of pPKCε, NADPH oxidase, MMP-9, and ERG in the LV, S, and RV of the heart, which were suppressed by either CPU0213 or aminoguanidine. It indicates that the ET-ROS pathway plays a role in the dispersed distribution of bioactive substances following sustained β-receptor stimulation.     

映山红花总黄酮对盐酸异丙肾上腺素诱导大鼠心肌缺血的保护作用

目的观察映山红花总黄酮(TFR)对盐酸异丙肾上腺素诱导的实验性心肌缺血的保护作用。方法采用皮下(sc)注射盐酸异丙肾上腺素(Iso)(8 mg.kg-1×2 d)诱导大鼠实验性心肌缺血模型,测定血清中MDA含量、GSH-PX活力、SOD及心肌组织中ATPase活性。同时行心肌组织病理组织学检查。结果TFR 30 mg.kg-1显著降低血清中MDA的生成,30,15 mg.kg-1及60,30 mg.kg-1升高SOD,GSH-PX的活力,60,30 mg.kg-1TFR可抑制心肌组织中Na -K -ATPase,Ca2 -Mg2 -AT-Pase,总ATPase活力的降低,TFR 60,30 mg.kg-1能显著改善sc Iso后心肌病理损伤程度,降低其病理损伤评分。结论TFR对盐酸异丙肾上腺素诱导的实验性心肌缺血有保护作用,其机制可能与减少体内自由基生成、改善心肌能量代谢有关。     

氧化苦参碱抑制异丙肾上腺素诱导大鼠慢性心力衰竭及对ADMA代谢通路的影响

目的：探讨氧化苦参碱抑制异丙肾上腺素（ISO）诱导大鼠慢性心力衰竭及其对非对称二甲基精氨酸（ADMA）代谢通路的影响。 方法：雄性Sprague-Dawley大鼠,皮下注射ISO 5 mg·kg^-1·d^-1,连续给药7 d诱发大鼠慢性心力衰竭。氧化苦参碱（100,50 mg·kg^-1）于ISO注射前7 d灌胃给药,共14 d。检测血清学指标、心功能血流动力学参数、心脏质量,并观察心肌组织病理变化,同时采用Western blotting法测定相关蛋白的表达。 结果：氧化苦参碱（100,50 mg·kg^-1）可显著降低ISO诱导的心力衰竭大鼠升高的血清心肌肌钙蛋白I（cTn I）水平,改善左心室收缩和舒张功能及左心室重构,显著减轻ISO致大鼠心肌的病理学改变。还可降低ISO诱导心力衰竭大鼠血清ADMA含量（P<0.01）,增加心室肌组织中二甲基二甲胺水解酶2（DDAH2）蛋白的表达（P<0.01）,但对ISO诱导升高的蛋白精氨酸甲基转移酶1（PRMT1）无影响。 结论：氧化苦参碱可改善ISO诱导的慢性心力衰竭大鼠的心功能,抑制心室重构,其作用机制与降低血清ADMA水平和增高心肌组织DDAH2表达水平有关。     

药效学筛选表征丹参二萜醌组分整体性质的代表性成分的研究

目的: 筛选药理作用与丹参二萜醌组分整体药理作用无显著性差异的主成分的组合,从而确定能够表征丹参二萜醌组分整体性质的代表性成分的配伍形式. 方法: 根据体外药效实验结果,结合腹腔注射盐酸异丙肾上腺素(ISO)诱导的大鼠急性心肌缺血模型,从心电图(J点的变化)、酶学指标(SOD,MDA,CK,LDH)以及病理学(心肌组织形态学变化)3个方面比较丹参二萜醌组分、主成分A组合以及主成分B组合的药理作用,从中筛选出能够代表丹参二萜醌组分整体性质的配伍形式. 结果: 丹参二萜醌高剂量组和主成分B高剂量组在各方面的药理作用相似,均无显著性差异. 结论: 丹参二萜醌组分高剂量组和主成分B高剂量组对ISO诱导的心肌缺血具有一定的治疗作用,且疗效相当,因此,初步认为主成分B组中4个成分能够作为丹参二萜醌组分的代表性成分.     

通心络胶囊对异丙肾上腺素致大鼠心肌损伤保护作用的实验研究

目的，探讨通心络胶囊对异丙肾上腺素致心肌损伤的保护作用，方法：于大鼠皮下注射异丙肾上腺素（85mg/kg)制备心肌损伤模型，34只大鼠随机分成生理盐水对照组，丙肾上腺素组及通心络胶囊干预组。HE染色及DNA末端标记法（TUNEL）分别检测心肌组织病理改变及心肌细胞凋亡的变化，透射电镜检测心肌细胞超微结构的变化。结果：生理盐水对照组无细胞变性与坏死，仅见极少凋亡阳性细胞；异丙肾上腺素组有明显心肌组织坏死。心肌凋亡细胞增多，电镜观察有凋亡细胞特征形态改变，通心络干预后心肌细胞坏死及凋亡均显著减轻。结论：异丙肾上腺素可致大鼠心肌组织坏死与凋亡，通心络胶囊可通过抑制心肌细胞坏死与凋亡而减轻心肌损伤。