CAJ | 학술논문

目的探讨微小RNA(miRNA)-214对慢性间歇低氧大鼠心肌细胞凋亡的影响及机制.方法 SD雄性大鼠20只,按随机数字表法随机分为慢性间歇低氧组(间歇性低氧舱内饲养8 h/d,共6周)和对照组(正常饲养)各10只.实验结束时通过颈动脉插管测定其血液动力学指标,TUNEL法检测大鼠心肌细胞凋亡,实时定量PCR测定心肌中miRNA-214及靶基因缺氧诱导因子-1 α(HIF-1 α)的变化;采用Western印迹法检测心肌组织中凋亡相关蛋白的相对表达量.结果慢性间歇低氧组左室舒张末压显著高于对照组[(4.1±0.5)比(2.7±0.4) mmHg](1 mmHg=0.133 kPa),而左室内压最大下降速率[(3 005±86)比(5 918±112)mmHg/s]、左室内压最大上升速率[(4 118±76)比(7 547±271) mmHg/s]和左室收缩压[(90.7±2.5)比(132.7±5.5) mmHg]均显著低于对照组(均P ＜0.001);慢性间歇低氧组心肌细胞凋亡指数显著高于对照组,miRNA-214相对表达量显著低于对照组,其靶基因HIF-1α相对表达量显著高于对照组(均P＜0.001);慢性间歇低氧组凋亡相关蛋白半胱氨酸天冬氨酸蛋白酶(caspase)-3、caspase-8及脂肪酸合成酶(Fas)、B细胞淋巴瘤-2(Bcl-2)相关X蛋白(Bax)的相对表达量均显著高于对照组,Bcl-2相对表达量显著低于对照组(均P＜0.001).结论慢性间歇性低氧可引起大鼠左心室收缩和舒张功能降低,miRNA-214能调控其靶基因HIF-1α,激活Fas死亡受体凋亡通路,影响慢性间歇性低氧诱导大鼠心肌细胞凋亡.
목적 탐토미소RNA(miRNA)-214대만성간헐저양대서심기세포조망적영향급궤제.방법 SD웅성대서20지,안수궤수자표법수궤분위만성간헐저양조(간헐성저양창내사양8 h/d,공6주)화대조조(정상사양)각10지.실험결속시통과경동맥삽관측정기혈액동역학지표,TUNEL법검측대서심기세포조망,실시정량PCR측정심기중miRNA-214급파기인결양유도인자-1 α(HIF-1 α)적변화;채용Western인적법검측심기조직중조망상관단백적상대표체량.결과 만성간헐저양조좌실서장말압현저고우대조조[(4.1±0.5)비(2.7±0.4) mmHg](1 mmHg=0.133 kPa),이좌실내압최대하강속솔[(3 005±86)비(5 918±112)mmHg/s]、좌실내압최대상승속솔[(4 118±76)비(7 547±271) mmHg/s]화좌실수축압[(90.7±2.5)비(132.7±5.5) mmHg]균현저저우대조조(균P ＜0.001);만성간헐저양조심기세포조망지수현저고우대조조,miRNA-214상대표체량현저저우대조조,기파기인HIF-1α상대표체량현저고우대조조(균P＜0.001);만성간헐저양조조망상관단백반광안산천동안산단백매(caspase)-3、caspase-8급지방산합성매(Fas)、B세포림파류-2(Bcl-2)상관X단백(Bax)적상대표체량균현저고우대조조,Bcl-2상대표체량현저저우대조조(균P＜0.001).결론 만성간헐성저양가인기대서좌심실수축화서장공능강저,miRNA-214능조공기파기인HIF-1α,격활Fas사망수체조망통로,영향만성간헐성저양유도대서심기세포조망.
Objective To observe the effects of chronic intermittent hypoxia (CIH) on myocardial cell apoptosis and explore the mechanism of microRNA-214 (miRNA-214) expression for myocardial cell apoptosis and cardiac dysfunction.Methods A total of 20 adult male Sprague-Dawley rats were randomized into two groups (n =10 each):for CIH group,the rats were raised in a CIH chamber 8 h daily for 6 weeks; for normal control (NC) group,the animal were exposed to normoxic air 7 h daily for 6 weeks.Hemodynamic values and myocardial function were measured via a cannula inserted into right common carotid artery.Myocardial cell apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method.The expressions of miRNA-214 and hypoxia-inducible factor-1α (HIF-1o) mRNA were observed by real-time polymerase chain reaction (PCR).The expressions of such apoptosis-related proteins as fatty acid synthase (Fas),caspase 3,caspase 8,B-cell lymphoma-2 (Bcl-2) and Bcl-2-Associated X Protein (Bax) were detected by Western blot.Results Compared with NC group,left ventricle end diastolic pressure (LVEDP) ((4.1 ±0.5) vs (2.7 ±0.4) mmHg,1 mmHg =0.133 kPa) increased,maximal rate of pressure decline (-dp/dtmax) ((3 005 ± 86) vs (5 918 ± 112) mmHg/s),maximal rate of pressure development (+ dp/dtmax) ((4 118 ± 76) vs (7 547 ± 271) mmHg/s) and left ventricular systolic pressure (LVSP) ((90.7 ± 2.5) vs (132.7 ± 5.5) mmHg] decreased in CIH group (all P ＜0.001).There were significantly more TUNEL positive cells in CIH group versus NC group (P ＜ 0.001).The expression of miRNA-214 was significantly lower in CIH group than that in NC group (P ＜0.001).In addition,HIF-1α mRNA level was significantly higher in CIH group than that in NC group (P ＜0.001).The expressions of caspase 3,caspase 8,Fas and Bax increased significantly in CIH group versus NC group (all P ＜ 0.001),suggesting increased apoptosis of myocardial cells in CIH group.Compared with NC group,the expression of Bcl-2 decreased significantly in CIH group (P ＜ 0.001).Conclusions CIH may decrease the hemodynamic values and myocardial function in rats.The expression of miRNA-214 in CIH group is significantly depressed through accelerated apoptosis of myocardial cells.