Una Disminución en el Contenido de la Isoforma Gigante de Obscurina durante el Desarrollo de Lesión Miocárdica...

We studied changes in the content of obscurin and the corresponding mRNA in the left ventricle of rat heart during the development of isoprenaline-induced myocardial injury. Myocardial injury was induced by subcutaneous injection of β-adrenoreceptor agonist isoprenaline hydrochloride at a dose of 150 mg/kg of body weight twice with a 24-h interval. On day 14, the animals were euthanized. An increase (by 28.7%; p ≤ 0.01) in heart weight, as well as an increase (by 17.7%; p ≤ 0.01) in the heart-to-body weight ratio in rats after isoprenaline injection were observed, indicating the development of cardiac muscle hypertrophy. Western blotting with antibodies specific to the N-sequence of rat obscurin previously produced by us revealed a 1.2-fold decrease (p ≤ 0.01) in the content of the A-isoform (880 kDa) of this protein in the left ventricle of the rat heart after isoprenaline injection. This decrease was observed against the background of elevated content (4.2-fold; p ≤ 0.01) of obscurin mRNA. The role of reduced obscurin content in the deterioration of heart function during the development of isoprenaline-induced myocardial injury is discussed.