1. ¹Division of Cardiovascular Medicine, Department of Cardiology, Gene Therapy Program, University of Arkansas for Medical Sciences, Little Rock, AR, USA
2. ²Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, Changsha, China

Correspondence: Professor JL Mehta, Division of Cardiovascular Medicine, University of Arkansas for Medical Sciences, 4301 W Markham, Mail Slot 532, Little Rock, Arkansas, AR 72205, USA. E-mail: mehtaJL@uams.edu

³These authors contributed equally to this work.

Received 24 April 2007; Revised 14 August 2007; Accepted 21 September 2007; Published online 15 November 2007.

Abstract

Transforming growth factor ₁ (TGF₁) has been purported to protect tissues from ischemia–reperfusion (I-R) injury. This study was designed to examine if overexpression of TGF₁ using adeno-associated virus type 2 (AAV) protects cardiomyocytes from reoxygenation injury. TGF₁ was overexpressed in cultured HL-1 mouse cardiomyocytes by transfection with AAV/TGF₁^Latent or with AAV/TGF₁^ACT (active TGF₁). TGF₁ upregulation reduced cardiomyocyte apoptosis and necrosis induced by 24 h of hypoxia followed by 3 h of reoxygenation concomitant with reduction in reactive oxygen species release, activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and NF-B expression. Transfection with AAV/TGF₁^ACT was superior to that with AAV/TGF₁^Latent. To determine if AAV/TGF₁^ACT upregulation in vivo would induce cardioprotection from I-R injury, rat hearts were injected with AAV/TGF₁^ACT or phosphate-buffered saline (PBS). Six weeks later, TGF₁^ACT was upregulated throughout the myocardium. Following I-R, AAV/TGF₁^ACT-overexpressing rats had much smaller infarct size (P<0.01 vs PBS group), which was also related to reduced activation of NADPH oxidase and NF-B, and lower levels of malondialdehyde in I-R tissues. These data demonstrate that overexpression of TGF₁ by AAV can protect cardiac tissues from reperfusion injury, possibly via antioxidant mechanism. These findings suggest potential of TGF₁^ACT gene therapy for cardioprotection from I-R injury.