甜菜碱对阿霉素心脏毒性的作用及机制

Role of Betaine in Doxorubicin-Induced Cardiotoxicity

目的探究甜菜碱在阿霉素诱导的心脏毒性中的作用及机制。方法给予小鼠单次腹腔注射阿霉素(15 mg/kg)构建阿霉素心肌病模型,采用随机数字表法将48只小鼠分为生理盐水+生理盐水组、生理盐水+甜菜碱组、阿霉素+生理盐水组以及阿霉素+甜菜碱组共4组,每组12只。模型构建当天开始连续7 d给小鼠进行甜菜碱灌胃(800 mg·kg^(-1)·d^(-1)),对照组用同等体积生理盐水进行灌胃。灌胃结束后检测各组小鼠心脏超声并取材;用免疫组织化学染色检测脂质过氧化物水平;用TUNEL染色检测心脏凋亡水平;Western blot检测相关蛋白激酶B(AKT)、糖原合成酶激酶-3β(GSK-3β)表达水平;qPCR检测相关基因mRNA水平;试剂盒检测心肌损伤标志物和丙二醛以及胱天蛋白酶(caspase)-3水平。结果与对照组小鼠相比,阿霉素可以导致小鼠心功能受损(P<0.05),心肌损伤标志物水平升高(P<0.05),而甜菜碱可以保护小鼠心功能(P<0.05),降低心肌损伤标志物水平(P<0.05)。与对照组小鼠相比,阿霉素导致心脏中丙二醛、4-羟基壬烯醛水平升高(P<0.05),以及抗氧化酶(超氧化物歧化酶-2、谷胱甘肽过氧化物酶-1、过氧化氢酶)的mRNA水平降低(P<0.05),甜菜碱可以降低丙二醛、4-羟基壬烯醛水平(P<0.05),上调抗氧化酶(超氧化物歧化酶-2、谷胱甘肽过氧化物酶-1、过氧化氢酶)的mRNA水平(P<0.05)。与对照组小鼠相比,阿霉素可以导致小鼠心脏中caspase-3活性增加(P<0.05),TUNEL阳性细胞增多(P<0.05),甜菜碱处理可以降低caspase-3活性,降低TUNEL阳性细胞率(P<0.05)。与对照组小鼠相比,阿霉素小鼠心脏中AKT的活性降低,GSK-3β的活性增加(P<0.05),而甜菜碱可以增加AKT的活性,降低GSK-3β的活性(P<0.05)。结论甜菜碱可以减轻阿霉素引起的心脏氧化应激损伤和心肌细胞凋亡,而这些作用可能是通过激活AKT/GSK-3β实现的。

Objective To investigate the role and mechanism of betaine in doxorubicin-induced cardiotoxicity.Methods Doxorubicin-induced cardiomyopathy model was established by a single intraperitoneal injection of doxorubicin(DOX,15 mg/kg)in mice.48 mice were randomly divided into 4 groups,including normal saline+normal saline group,normal saline+betaine group,DOX+normal saline group,and DOX+betaine group,with 12 mice per group.Mice were given betaine(800 mg·kg^(-1)·d^(-1))intragastric administration for 7 consecutive days from the day of model construction,and the control group was given the same volume of normal saline intragastric administration.At the end of intragastric administration,cardiac ultrasound was detected and samples were taken.The level of lipid peroxide was detected by immunohistochemical staining,TUNEL staining was used to detect cardiac apoptosis.Western blot was used to detect the expression levels of AKT and GSK-3βmRNA levels of related genes were detected by qPCR.The levels of cTnI,LDH,MDA,4-HNE,and caspase-3 were detected.Results Compared with the control group,DOX could damage the heart function of mice(P<0.05)and increase the level of myocardial injury markers(P<0.05),while betaine could protect the heart function of mice(P<0.05)and decrease the level of myocardial injury markers(P<0.05).Compared with the control group,DOX increased MDA and 4-HNE levels(P<0.05),and decreased mRNA levels of antioxidant enzymes(SOD-2,GPx-1,and CAT)in the heart(P<0.05).Betaine decreased MDA and 4-HNE levels(P<0.05).The mRNA levels of antioxidant enzymes(SOD-2,GPx-1,and CAT)were up-regulated(P<0.05).Compared with the control group,DOX could increase the activity of caspase-3 and TUNEL-positive cells in the heart of mice(P<0.05).Betaine treatment could decrease the activity of caspase-3 and the rate of TUNEL-positive cells(P<0.05).Compared with control mice,the activity of AKT in the heart of doxorubicin-treated mice was decreased and the activity of GSK-3βwas increased(P<0.05),while betaine increased the activity of AKT and decreased the activity of GSK-3β(P<0.05).Conclusion Betaine can reduce oxidative stress injury and apoptosis of cardiomyocytes induced by DOX,and these effects may be realized by activating AKT/GSK-3βsignaling pathway.