amiodarone induced morphological changes in rabbit pneumocytes

objective: amiodarone as an iodinated benzofuran derivative is a potent antiarrhythmic agent currently used for the treatment of ventricular arrhythmias. pulmonary toxicity is one of the complications of amiodarone therapy. the aim of this study was to determine the toxicity of amiodarone for pneumocytes. materials and methods: 14 male white new zealand rabbits were divided in a control group and an experimental group. the experimental group was subjected to intra peritoneal injection with a single daily dose of 80 mg/kg amiodarone for two weeks. the control group received only normal saline. at the end of the injection period, the two groups were anesthetized and perfused with karnovsky fixative. the lung tissue was removed and fixed, then prepared for light and electron microscope studies. morphometric studies were made on sections to find nucleus profile dimensions. results: light microscope observation showed acute changes in the alveolus including congestion of alveolar capillaries and infiltration of red blood cells (rbcs) into the lumen of the alveoli. electron microscope study of lung tissue revealed abnormal inclusion bodies within type ιι & ι pneumocytes. the micrographs also showed the presence of vacuoles in 5% of the type ιι pneumocytes. morphometric studies showed that the nucleus of the cells in the experimental group were smaller than in the control group (p<0.01). conclusion: these results indicate that amiodarone administration can cause damage to pnuemocytes and the alveolus of rabbit lung, so the effectiveness of amiodarone in long term treatment of heart failure patients is limited because of the development of lung toxicity.