- 作者: Bin He; Jian Xiao; An-Jing Ren; Yu-Feng Zhang; Hao Zhang; Min Chen; Bing Xie; Xiao-Gang Gao; Ying-Wei Wang
- 作者服務機構: Department of Anesthesiology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Kongjiang Road, Shanghai, China,
- 中文摘要: --
- 英文摘要:
Background: Ischemic postconditioning (IPost) has aroused much attention since 2003 when it
was firstly reported. The role of microRNAs (miRNAs or miRs) in IPost has rarely been reported.
The present study was undertaken to investigate whether miRNAs were involved in the protective
effect of IPost against myocardial ischemia-reperfusion (IR) injury and the probable mechanisms
involved.
Methods: Thirty SD rats weighing 250-300 g were equally randomized to three groups: Control
group, where the rats were treated with thoracotomy only; IR group, where the rats were treated
with ischemia for 60 min and reperfusion for 180 min; and IPost group, where the rats were treated
with 3 cycles of transient IR just before reperfusion. The extent of myocardial infarction, LDH and
CK activities were measured immediately after treatment. Myocardial apoptosis was detected by
TUNEL assay. The myocardial tissue was collected after IR or IPost stimulation to evaluate the
miRNAs expression level by miRNA-microarray and quantitative real-time RT-PCR. Real-time
PCR was conducted to identify changes in mRNA expression of apoptosis-related genes such as
Bcl-2, Bax and Caspase-9 (CASP9), and Western blot was used to compare the protein expression
level of CASP9 in the three groups. The miRNA mimics and anti-miRNA oligonucleotides (AMO)
were transferred into the cultured neonatal cardiomyocytes and myocardium before they were
treated with IR. The effect of miRNAs on apoptosis was determined by flow cytometry and TUNEL
assay. CASP9, as one of the candidate target of miR-133a, was compared during IR after the
miR-133a mimic or AMO-133a was transferred into the myocardium.
Results: IPost reduced the IR-induced infarct size of the left ventricle, and decreased CK and LDH
levels. TUNEL assay showed that myocardial apoptosis was attenuated by IPost compared with IR.
MiRNA-microarray and RT-PCR showed that myocardial-specific miR-1 and miR-133a were
down-regulated by IR, and up-regulated by IPost compared with IR. Furthermore, IPost
up-regulated the mRNA expression of Bcl-2, down-regulated that of Bax and CASP9. Western blot
showed that IPost also down-regulated the CASP9 protein expression compared with IR. The
results of flow cytometry and TUNEL assay showed that up-regulation of miR-1 and miR-133a
decreased apoptosis of cardiomyocytes. MiR-133a mimic down-regulated CASP9 protein
expression and attenuated IR-induced apoptosis.
Conclusion: MiRNAs are associated with the protective effect of IPost against myocardial IR
injury. IPost can up-regulate miR-1 and miR-133a, and decrease apoptosis of cardiomyocyte.
Myocardial-specific miR-1 and miR-133a may play an important role in IPost protection by
regulating apoptosis-related genes. MiR-133a may attenuate apoptosis of myocardiocytes by
targeting CASP9. - 中文關鍵字: --
- 英文關鍵字: --