Decreased gene expression of KACh and KATP channels in hyperthyroid rabbit atria

Abstract

Cardiac hypertrophy is a common myocardial structural abnormality which may cause heart failure. Many studies have shown that cardiac hypertrophy can be induced by hyperthyroidism. Ligand-gated potassium channels have been reported to be involved in various biological processes in the cardiovascular system, such as GPCR coupled K_ACh and metabolism sensor K_ATP channel. It is unclear whether the gene expression of K_ACh and K_ATP was altered in hyperthyroid rabbit atria. We aimed to investigate the expression of K_ACh and K_ATP genes in rabbit atria in our experimental model. We established an effective hyperthyroidism-induced cardiac hypertrophy animal model through an injection of T4. H&E staining and RT-PCR were used to observe the histomorphological damages and alteration of gene expression. The results showed that the heart weight, heart rate significantly increased in T4-treated rabbits. The systolic pressure increased from 115.60 mmHg to 152.6 mmHg in T4-treated rabbits. The expression of K_ACh and K_ATP genes was decreased in the atria of hyperthyroidism-induced cardiac hypertrophied rabbits. These findings indicated that the decreased gene expression of K_ACh and K_ATP may be related to hyperthyroidism-induced cardiac hypertrophy and atrial fibrillation.

Keywords: Hyperthyroidism; KACh channel; KATP channel; cardiac hypertrophy; gene expression.