低能激光照射对大鼠心肌梗死后心肌组织中SOD和MDA影响的研究

Effect of Low Level Laser Irradiation to SOD Activity and MDA Content in Infracted Myocardial Tissue of Rats

目的:观察低能激光照射(LLLI)对心肌梗死后大鼠心肌组织中超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量的影响,并探讨其意义。方法:SD大鼠120只分为三组:假手术组(30只)、对照组(45只)、LLLI治疗组(45只)。对照组和LLLI治疗组大鼠10%水合氯醛腹腔注射麻醉后开胸结扎左冠状动脉前降支,制备大鼠心肌梗死模型,假手术组手术操作同模型制作,但穿针后不结扎缝线。3周后所有大鼠再次开胸,治疗组进行LLLI(635nm,6mW,125s,0.96J/cm^(2)),对照组和假手术组操作同治疗组,但不开通低能激光设备,于二次开胸处理后1h、24h、48h、72h、1周采用黄嘌呤氧化酶法和硫代巴比妥酸(TBA)法分别检测各组大鼠梗死心肌组织SOD活性和MDA含量,并做心肌组织病理学观察。结果:心肌梗死后,对照组和LLLI治疗组大鼠梗死心肌组织中SOD活性明显降低(P<0.05),1~48h时LLLI治疗组SOD活性高于对照组(P<0.05),72h和1周时对照组和治疗组无明显差异;对照组和LLLI治疗组大鼠梗死心肌组织中MDA含量较假手术组大鼠明显增加(P<0.05),1~48h LLLI治疗组低于对照组(P<0.05),72h和1周时对照组和治疗组无明显差异。结论:低能激光照射可以显著增加大鼠梗死心肌组织中抗氧化物质的SOD活性,抑制脂质过氧化产物MDA含量的产生,对心肌组织有较好的保护作用。

Objective:To investigate effect of low level laser irradiation to SOD activity and MDA content in infracted myocardial tissue of rats.Methods:Myocardial infarction was created by the left anterior descending(LAD)coronary artery ligation in 90 rats.The surviving rats were divided randomly into control and laser groups,45 rats in each group.30 rats received a thoracotomy without coronary ligation(sham group).3 weeks after myocardial infarction,all the rats received a thoracotomy.The rats of laser group were exposed to a diode laser(635nm,6mW,125s,0.96J/cm^(2)).In the control and sham group,laser irradiation was not applied.1 hour,24 hours,48 hours,72 hours and 1 week after second thoracotomy,3~5 rats from each group were sacrificed and the infracted myocardial tissues were analyzed to determine SOD activity and MDA content at each time point.The myocardial infarction was determined from histological sections stained with HE.Results:Compared with the sham group,myocardial SOD activity was decreased and myocardial MDA content was increased in control and laser group significantly(P<0.05).In laser group,myocardial SOD activity was higher than that in the control group(P<0.05),and myocardial MDA content was lower than those in the control group(P<0.05),from 1 hour to 48 hours after LLLI.The differences between laser group and control group disappeared at 72 hours and 1 week after LLLI.Conclusion:Low level laser irradiation increases SOD activity and decreases MDA content in infracted myocardial tissue after myocardial infarction,and alleviates the myocardial injury.