Mechanisms of immature myocardial tolerance to ischemia: phenotypic differences in antioxidants, stress proteins, and oxidases.
Mechanisms of immature myocardial tolerance to ischemia: phenotypic differences in antioxidants, stress proteins, and oxidases.
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未成熟心肌缺血耐受的机制：抗氧化剂、应激蛋白和氧化酶的表型差异。
DOI：
10.1016/s0039-6060(05)80357-5
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发表时间：
1995
期刊：
影响因子：
3.8
通讯作者：
Brown,JM
中科院分区：
文献类型：
--
作者：
Rowland,RT;Meng,X;Ao,L;Terada,LS;Harken,AH;Brown,JM
背景研究表明新生心肌对缺血性损伤具有耐受性。虽然已经提出了这种保护的各种机制，氧化-抗氧化因子，应激蛋白的表达，并保护心肌缺血/再灌注（I/R）损伤之间的联系还没有在新生儿心肌。我们推测新生儿心肌对I/R的抵抗与氧自由基产生能力降低、自由基清除能力增强和应激蛋白表达增加有关。本研究的目的是检测新生和成年大鼠心脏I/R后的功能恢复，过氧化氢酶和黄嘌呤氧化酶（XO）活性，以及热休克蛋白72（HSP 72）的表达。（7 ~ 10天与60天）在60 mm Hg的非工作Langendorff装置上灌注（Krebs-Henseleit缓冲液，pH 7.4，37°C），并进行20分钟的全脑缺血和40分钟的再灌注。通过使用左心室导管记录左心室发展压力。结果新生大鼠心脏I/R后左室舒张压功能恢复率（66.0%±4.2%）高于I/R后（44.3%±3.5%）（P<0.05）。新生儿心肌的过氧化氢酶活性也有所增加（1027.9±20.6单位/gm对707.3±38.7单位/gm; p<0.05），而XO的活性相对于成人降低（0.23 ± 0.01 mU/gm对7.6 ± 1.4 mU/gm; p<0.05）。此外，HSP 72的表达是更大的新生儿比成人control.ConclusionsRelative成人心脏，新生大鼠心脏更耐受全球缺血再灌注损伤。这种改善的功能恢复与降低的氧化剂产生潜力（XO）、增加的清除能力（过氧化氢酶）和增强的应激蛋白表达（HSP 72）相关。
BackgroundPrevious work has suggested tolerance to ischemic injury in newborn myocardium. Although various mechanisms for this protection have been proposed, a link between oxidant-antioxidant factors, stress protein expression, and protection from cardiac ischemia/reperfusion (I/R) injury has not been made in newborn myocardium. We hypothesized that newborn myocardial resistance to I/R is related to decreased oxygen radical producing potential, increased free radical scavenging capacity and augmented stress protein expression. The purposes of the study were to examine in newborn and adult rat hearts (1) functional recovery from I/R, (2) catalase and xanthine oxidase (XO) activities, and (3) heat shock protein 72 (HSP 72) expression.MethodsIsolated rat hearts (7 to 10 days versus 60 days) were perfused on a noworking Langendorff apparatus at 60 mm Hg (Krebs-Henseleit buffer, pH 7.4, 37°C) and subjected to 20 minutes of global ischemia and 40 minutes of reperfusion. Left ventricular developed pressure was recorded by using a left ventricular catheter. Catalase and XO were measured by means of standard assays, and HSP 72 was assessed with in situ immunohistochemistry.ResultsNewborn rat hearts had greater percentage functional recovery of left ventricular developed pressure after I/R (66.0%±4.2% versus 44.3%±3.5%; p<0.05). The newborn myocardium also had increased catalase activity (1027.9±20.6 units/gm versus 707.3±38.7 units/gm; p<0.05), whereas the activity of XO was decreased relative to the adult (0.23+0.01mU/gm versus 7.6+1.4 mU/gm; p<0.05). Furthermore, the expression of HSP 72 was greater in the newborn than the adult control.ConclusionsRelative to adult hearts, newborn rat hearts are more tolerant to a global ischemic insult followed by reperfusion. This improved functional recovery is associated with decreased oxidant production potential (XO), increased scavenging capacity (catalase), and augmented stress protein expression (HSP 72).
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