Hui Liu1, Xibo Jing2, Aiqiao Dong1, Baobao Bai1, Haiyan Wang1. 1. Department of Cardiology, Tangdu Hospital, the Fourth Military University, Xi'an, China. 2. Department of Cardiology, the Second Affiliated Hospital of Shandong Traditional Chinese Medicine University, Jinan, China.
Abstract
BACKGROUND/AIMS: Myocardial ischemia/reperfusion (I/R) injury remains a great challenge in clinical therapy. Tissue inhibitor of metalloproteinases 3 (TIMP3) plays a crucial role in heart physiological and pathophysiological processes. However, the effects of TIMP3 on I/R injury remain unknown. METHODS: C57BL/6 mice were infected with TIMP3 adenovirus by local delivery in myocardium followed by I/R operation or doxorubicin treatment. Neonatal rat cardiomyocytes were pretreated with TIMP3 adenovirus prior to anoxia/reoxygenation (A/R) treatment in vitro. Histology, echocardiography, in vivo phenotypical analysis, flow cytometry and western blotting were used to investigate the altered cardiac function and underlying mechanisms. RESULTS: The results showed that upregulation of TIMP3 in myocardium markedly inhibited myocardial infarct areas and the cardiac dysfunction induced by I/R or by doxorubicin treatment. TUNEL staining revealed that TIMP3 overexpression attenuated I/R-induced myocardial apoptosis, accompanied by decreased Bax/Bcl-2 ratio, Cleaved Caspase-3 and Cleaved Caspase-9 expression. In vitro, A/R-induced cardiomyocyte apoptosis was abrogated by pharmacological inhibition of reactive oxygen species (ROS) production or MAPKs signaling. Attenuation of ROS production reversed A/R-induced MAPKs activation, whereas MAPKs inhibitors showed on effect on ROS production. Furthermore, in vivo or in vitro overexpression of TIMP3 significantly inhibited I/R- or A/R-induced ROS production and MAPKs activation. CONCLUSION: Our findings demonstrate that TIMP3 upregulation protects against cardiac I/R injury through inhibiting myocardial apoptosis. The mechanism may be related to inhibition of ROS-initiated MAPKs pathway. This study suggests that TIMP3 may be a potential therapeutic target for the treatment of I/R injury.
BACKGROUND/AIMS: Myocardial ischemia/reperfusion (I/R) injury remains a great challenge in clinical therapy. Tissue inhibitor of metalloproteinases 3 (TIMP3) plays a crucial role in heart physiological and pathophysiological processes. However, the effects of TIMP3 on I/R injury remain unknown. METHODS: C57BL/6 mice were infected with TIMP3 adenovirus by local delivery in myocardium followed by I/R operation or doxorubicin treatment. Neonatal rat cardiomyocytes were pretreated with TIMP3 adenovirus prior to anoxia/reoxygenation (A/R) treatment in vitro. Histology, echocardiography, in vivo phenotypical analysis, flow cytometry and western blotting were used to investigate the altered cardiac function and underlying mechanisms. RESULTS: The results showed that upregulation of TIMP3 in myocardium markedly inhibited myocardial infarct areas and the cardiac dysfunction induced by I/R or by doxorubicin treatment. TUNEL staining revealed that TIMP3 overexpression attenuated I/R-induced myocardial apoptosis, accompanied by decreased Bax/Bcl-2 ratio, Cleaved Caspase-3 and Cleaved Caspase-9 expression. In vitro, A/R-induced cardiomyocyte apoptosis was abrogated by pharmacological inhibition of reactive oxygen species (ROS) production or MAPKs signaling. Attenuation of ROS production reversed A/R-induced MAPKs activation, whereas MAPKs inhibitors showed on effect on ROS production. Furthermore, in vivo or in vitro overexpression of TIMP3 significantly inhibited I/R- or A/R-induced ROS production and MAPKs activation. CONCLUSION: Our findings demonstrate that TIMP3 upregulation protects against cardiac I/R injury through inhibiting myocardial apoptosis. The mechanism may be related to inhibition of ROS-initiated MAPKs pathway. This study suggests that TIMP3 may be a potential therapeutic target for the treatment of I/R injury.