多西环素对慢性间歇缺氧所致的心房重构的改善作用

Effect of doxycycline on chronic intermittent hypoxia-induced atrial remodeling

目的探究多西环素对慢性间歇缺氧(CIH)所致大鼠心房重构的相关干预机制。方法 45只雄性SD大鼠随机分为对照组、慢性间歇缺氧组(模型组)及多西环素干预组(干预组),每组各15只。模型组大鼠每日接受间歇缺氧6h,持续30d,干预组大鼠在间歇缺氧的基础上给予多西环素进行干预。行超声心动图检查之后,每组随机挑选5只进行体外心脏电生理学实验,剩余10只大鼠留取心房组织进行病理学及分子生物学实验。Masson染色观察大鼠心房肌组织纤维化程度,实时荧光定量聚合酶联反应和Western blot用于检测心房组织中微小RNA(miR)-1、miR-21、miR-29b、miR-30、miR-133a、miR-328、转化生长因子β1(TGF-β1)及结缔组织生长因子(CTGF)表达水平的变化。结果与对照组比较,模型组大鼠左心房胶原分数和心房颤动(AF)诱发率明显增加[(6.40±0.84)%vs(1.50±0.23)%和(36.0±10.8)%vs(24.0±14.3)%,P<0.05],心房组织miR-1、miR-21、miR-133a、miR-328、TGF-β1及CTGF的表达水平明显升高。与模型组比较,干预组左心房胶原分数明显降低[(2.84±0.69)%vs(6.40±0.84)%,P<0.05],AF诱发率有所改善,但差异无统计学意义(P>0.05),miR-21、miR-133a、TGF-β1/β肌动蛋白(β-actin)及CTGF/β-actin的表达水平明显改善。结论 CIH可导致大鼠心房的结构重构和电重构,而miR-1、miR-21、miR-133a、miR-328、TGF-β1及CTGF表达水平的升高在心房重构中具有重要作用,多西环素可能通过干预miR-133a、TGF-β1、CTGF信号通路进而改善CIH导致的心房重构。

Objective To study the effect of doxycycline on chronic intermittent hypoxia（CIH）-induced atrial remodeling and its mechanism.Methods Forty-five male SD rats were divided into control group（n=15）,CIH group（model group,n=15）and doxycycline treatment group（intervention group,n=15）.The rats in model group were exposed to CIH（6 ha day for 30 days）,those in intervention group exposed to CIH were treated with doxycycline for 30 days.After the animals underwent echocardiography,5 rats randomly selected from each group underwent external heart electrophysiological test and atrial tissue sample was taken from the other 10 rats for histological and molecular biological experiments to assay the fibrosis of atrial tissue with Masson staining.Expressions of miR-1,miR-21,miR-29 b,miR-30,miR-133 a,miR-328,TGF-β1 and CTGF were detected by RT-qPCR and Western blot respectively.Results The left atrial interstitial collagen fraction and AF inducibility were significantly higher in model group than in control group（6.40%±0.84%vs1.50%±0.23%,36.0%±10.8% vs24.0%±14.3%,P〈0.05）.The expression levels of miR-1,miR-21,miR-133 a,miR-328,TGF-β1 and CTGF were significantly higher in model group than in control group.The left atrial interstitial collagen fraction was significantly lower in intervention group than in model group（2.84%±0.69%vs 6.40%±0.84%,P〈0.05）and no significant difference was found in AF inducibility between the two groups（P〉0.05）.The expression levels of miR-21,miR-133 a,TGF-β1/β-actin and CTGF/β-actin were significantly lower in intervention group than in model group.Conclusion CIH can induce atrial remodeling.Elevated expression levels of miR-1,miR-21,miR-133 a,miR-328,TGF-β1 and CTGF play an important role in atrial remodeling.Doxycycline can improve CIH-induced atrial remodeling by regulating the signaling pathway of miR-133 a,TGF-β1 and CTGF.