酸性HEPES—KH液对离体未成熟心肌的作用

Protective effects of acidic HEPES-KH reperfusate medium on immature cardium in neonatal rabbits

目的观察不同pH值HEPES—KH复灌液对离体未成熟心肌的影响。方法建立Iangendorff离体灌注模型，分为2组：缺血／再灌（I／R，n=8），用pH 7．4HEPES—KH液灌流20min，缺血60min，恢复灌注30min；酸性灌注组（E，n=8），用pH7．4HEPES—KH液灌流20min，缺血60min后，应用pH6．8．7．1和7．4HEPES．KH液顺次灌注5、5、20min。以血流动力学指标、生化指标作为观察指标。结果E组与I／R组比较，左心室功能恢复、三磷酸腺苷含量（ATP）（0．93±0．12比0．56±0．04，P〈0．01）、超氧化物歧化酶活性（183．47±9．72比120．17±6．21，P〈0．01）、心肌线粒体Ca^2＋ -ATP酶活性（16．74±1．42比6．78±0．64，P〈0．01）和心肌线粒体合成ATP的能力（105．37±9．51比50．83±4．75，P〈0．01）明显增强，在心肌含水量（74．56±1．68比86．20±2．33，P〈0．01）、丙二醛含量（1．97±0．17比2．88±0．32，P〈0．01）、肌酸激酶（64．56±4．69比88．48±5．86，P〈0．01）和乳酸脱氢酶漏出率漏出率（96．41±6．57比128．42±9．80，P〈0．01）、心肌细胞内Ca^2＋含量（2．25±0．28比4．48±0．74，P〈0．01）和心肌线粒体Ca^2＋含量（36．10±4．05比68．29±6．90，P〈0．01）明显减少。结论复灌初期应用梯度酸性复灌液对离体未成熟心肌具有明显保护作用。

Objective To study the protective effects of different pH HEPES-KH reperfusate solutions on immature myodium. Methods The isolated Langendorff perfused model from immature rabbit hearts was established. The rabbits in ischemia/reperfusion （I/R） group were perfused with pH7.4 HEPES-KH solutions preischemia and postischemia. In experimental （E） group, pH 6. 8, pH 7. 1 and pH 7.4 HEPES-KH solutions were perfused for 5, 5 and 20 min postischemia, respectively. The hemodynamics and biochemistry were tested. Results The left ventricular function was significantly improved, adenosine triphosphate （ATP） content （0. 93 ± 0. 12 vs 0. 56 ± 0.04, P 〈 0. 01 ）, superoxide dismutase activity （ 183.47 ± 9.72 vs 120. 17 ± 6. 21, P 〈 0. 01 ）, Ca2＋ -ATPase activity of mitothondia （ 16. 74 ±1.42 vs 6. 78± 0. 64,P 〈 0. 01 ）, ATP activity of mitochondria （ 105.37 ± 9. 51 vs 50. 83 ± 4. 75, P 〈 0.01 ） were significantly increased in E group as compared with those in I/R group. Myocardial water content （74. 56 ± 1.68 vs 86.20 ± 2. 33,P 〈 0. 01 ）, malondialdehyde content （ 1.97 ± 0. 17 vs 2. 88± 0. 32, P 〈 0. 01 ）, dehydrogenase （64. 56 ± 4. 69 vs 88.48 ±5.86,P 〈 0. 01 ） and creatine kinase leakage （96.41 ± 6.57 vs 128.42 ±9.80,P〈0.01）, myocardial cell Ca2＋ content （2.25 ±0.28 vs 4.48 ±0.74,P〈 0. 01 ） and mitochondrial Ca2＋ content （ 36. 10 ± 4. 05 vs 68.29 ± 6. 90, P 〈 0.01 ） in E group were reduced as compared with those in I/R group. Conclusion pH paradox might be one of important mechnisms for immature myocardial I/R injury, and acidic perfusate, at the beginning of reperfusion, might attenuate pH paradox and ameliorate functional recovery on isolated immature rabbit hearts.