Shatoor et al J Clin Med Res • 2012;4(3):190-196 Figure 1. Electron micrographs from cardiac atria of control rats. A. A semithin section showing clarified intercalated discs (arrows), typical cross striations of muscle fibres (star), and many rows of mitochondria (double arrows). (B) blood capillary. B. The striation pattern (stars) with its typical alteration and dense mitochondria (M) rich in cristae (Bar = 200 nm). C. The striation pattern (stars) with its typical alteration and dense mitochondria (M) rich in cristae, euchromatic nucleus (N) with its nucleolus (n) and closely packed atrionatriuretic factor (ANF) granules (An) (Bar =1 µm). D. The striation pattern (stars) with its typical alteration and step-like interca- lated disc (arrow) with adherent fascia (Bar = 500 nm). (x: 1000). by reducing or preventing oxidative damage. This lipid sol- uble vitamin prevents lipid peroxidation chain reactions in cellular membranes by interfering with the propagation of lipid radicals. Recent histological and immunohistochemical studies have shown a protective role of vitamin E against oxidative stress injury and alteration in the architecture of liver and lungs of rats that received amiodarone [19, 20]. Therefore, the aim of the present study is to assess the ultrastructural changes of the rat heart after amiodarone ad- ministration and to test the possible protective effect of vita- min E co-administration. Materials and Methods Chemical agents Amiodarone (Chlorhydrate D’) was purchased from Sanofi (France), and alpha tocopherol acetate was purchased from Sigma-Aldrich (Buchs, Switzerland). Both compounds were used without further purification. Drug preparation Amiodarone alone or combined with alpha tocopherol ac- etate were dissolved in 2 mL vegetable oil to their final con- centration according to the weight of each animal. The doses of amiodarone and alpha tocopherol acetate used in this ex- periment were 54 mg/kg and 50 mg/kg, respectively. The dose of amiodarone selected in this study corresponds to the maximum human daily therapeutic dose converted into the equivalent rat dose according to Paget’s table [21]. The dose of alpha tocopherol was chosen as an effective antioxidant dose in rats according to Calfee-Mason et al [22]. Experimental animals The study was carried out in the Department of Anatomy at the College of Medicine, King Khalid University (Abha, Saudi Arabia) in October, 2011. Eighteen adult male albino Wistar rats weighing between 200 - 250 g and aged 6 months were used for the experimental procedure. The rats were ob- tained from the animal house of the College of Medicine, King Khalid University, Abha, Saudi Arabia. All rats were maintained in similar polypropylene cages of standard di- mensions at a temperature of 25 ± 1oC and a standard 12 h day/night cycle; the rats were housed in groups of 4 rats per cage (50 x 26 x 16 cm). The rats were fed rat chow and wa- ter ad-libitum. All procedures were approved by the Ethical Committee at King Khalid University Medical School and Articles © The authors | Journal compilation © J Clin Med Res and Elmer Press™ | www.jocmr.org 191