左旋卡尼汀預(yù)處理對(duì)離體兔心缺血再灌注致心肌損傷及MDA、SOD的影響

1、左旋卡尼汀預(yù)處理對(duì)離體兔心缺血/再灌注致心肌損傷及MDA、SOD的影響         10-10-30 09:49:00     編輯：studa20                       作者：趙寧軍，許鐵，葉英，燕憲亮，梁高永，劉蓓 【摘

2、要】  目的 觀察左旋卡尼?。↙-CN）預(yù)處理對(duì)離體兔心缺血/再灌注致心肌損傷及丙二醛（MDA）、超氧化物歧化酶（SOD）的影響。方法 采用離體兔心Langendorff灌注實(shí)驗(yàn)?zāi)Ｐ?離體兔心12只隨機(jī)分成缺血/再灌注組（I/R組）和L-CN預(yù)處理組，每組6只。I/R組灌注K-H液25 min，（兔心）4標(biāo)準(zhǔn)St.Thomas停搏液(K+ 16 mmol/L)至心臟停搏,45 min后恢復(fù)K-H液灌注20 min; L-CN預(yù)處理組灌注K-H液10 min，再予L-CN續(xù)灌15 min，余步驟同I/R組。測(cè)定再灌注末心肌組織中MDA、SOD的活性； 2，3，5-三苯基氯化四氮唑（TT

3、C）染色測(cè)定心肌存活面積百分比。結(jié)果 L-CN預(yù)處理組SOD活性明顯高于I/R組（P0.01），MDA含量明顯低于I/R組（P0.05）。L-CN預(yù)處理組心肌存活面積百分比高于I/R組(P0.05）。結(jié)論 L-CN預(yù)處理對(duì)高鉀停搏離體兔缺血/再灌注心臟具有抑制氧化應(yīng)激、提高抗氧化能力的作用，可減輕心肌損傷。 【關(guān)鍵詞】  缺血/再灌注損傷;離體心臟;左旋卡尼汀;預(yù)處理;家兔Abstract: Objective  To investigate the effects of L-carnitine (L-CN) preconditioning on levels of sup

4、eroxide dismutase (SOD) and malondialdehyde (MDA) against ischemia/reperfusion-induced myocardial injury in isolated rabbit hearts. Methods  The experiment was performed on isolated rabbit hearts perfused on Langendorff apparatus. 12 rabbit hearts were randomized into ischemia/reperfusion group

5、 (I/R group) and L-CN preconditioning group (n=6 each). The I/R group was firstly perfused with Krebs-Henseleit buffer (K-H) solution at 4 for 25 min, followed by St. Thomas solutions (K+ 16 mmol/L) until cardiac arrest for 45 min and then reperfused with K-H solution for 20 min. The treatment of L-

6、CN preconditioning group was similar to that of the I/R group, except that this group was initially perfused with K-H solution for 10 min and then perfused with L-CN. At the end of reperfusion, the contents of MDA, the activity of SOD were measured. The percentage of survival areas of myocardium was

7、 measured by using 2,3,5-triphenyltetrazolium chloride (TTC) stain. Results  In contrast to the findings in the I/R group, the percentages of surviving myocardium areas in the L-CN preconditioning group were higher (P<0.05). SOD content in L-CN preconditioning group was significant higher th

8、an that in I/R group (P<0.01). MDA content in L-CN preconditioning group was significantly lower than that in I/R group (P<0.05). Conclusion  L-CN preconditioning can attenuate the myocardium injury by inhibiting oxidative stress and increasing the anti-oxidative capacity to the isolated

9、rabbit heart undergoing cardiac ischemia due to high potassium-induced cardiac arrest and reperfusion.    Key words:  ischemia/reperfusion-induced injury; isolated heart;  L-carnitine; preconditioning; rabbit    成熟心肌的主要能量來(lái)源是脂肪酸,約占總能量來(lái)源的60%80%,且主要是依靠外源性脂肪酸來(lái)提供能量

10、。左旋卡尼?。↙-carnitine, L-CN）是人體脂肪酸代謝的必需輔助因子，可以改善心肌缺血時(shí)的異常代謝狀況，加速脂肪的-氧化，并增加葡萄糖的氧化利用1。本實(shí)驗(yàn)應(yīng)用離體兔心Langendorff灌注模型觀察L-CN預(yù)處理對(duì)高鉀停搏離體兔心缺血/再灌注損傷的影響，并探討其可能的作用機(jī)制。1  材料和方法1.1  材料 采用健康家兔（由徐州醫(yī)學(xué)院實(shí)驗(yàn)動(dòng)物中心提供）12只，雌雄不拘，體重2.22.5 kg,平均(2.3±0.2) kg。L-CN為美國(guó)Sigma公司產(chǎn)品，2,3,5三苯基氯化四氮唑（2,3,5-triphenyltetrazolium ch

11、loride, TTC）購(gòu)自上海國(guó)藥醫(yī)藥集團(tuán)公司，SOD、MDA測(cè)定試劑盒購(gòu)自南京建成生物工程研究所。其余試劑均為國(guó)產(chǎn)分析純。1.2  實(shí)驗(yàn)方法兔耳緣靜脈注射肝素300 U/kg，5 min后擊頭部致昏,迅速開胸取心連接于改良Langendorff灌注裝置上，以95% O2和5% CO2飽和Krebs-Henseleit溶液(K-H液)逆行灌注，溫度37，灌注壓力為750 mmHg (1 mmHg=0.133 kPa)。K-H液成分(mmol/L)：NaCl 118、 KCl 4.7、NaH2PO4 1.19、MgCl2 1.19、CaCl2 2.5、NaHCO3 24.8、葡萄糖1.1、EDTA-2Na 0.125，pH 7.4。采用離體兔心Langendorff灌注實(shí)驗(yàn)?zāi)Ｐ?根據(jù)預(yù)處理藥物濃度不同（參見Loster等2文獻(xiàn)），隨機(jī)分成缺血/再灌注組（I/R組）、左旋卡尼汀預(yù)處理組（L-CN預(yù)處理組），每組6只。離體心臟以95%O2和5%CO2混合氣體飽和的K-H液平衡灌注10 min后，I/R組繼續(xù)灌注K-H液15 min。L-CN預(yù)處理組在平衡灌注后予濃