The present study is designed to investigate the accumulative effect of aging on the histological and immunohistochemical (IHC) changes of rabbit's cardiac muscle and the protective role of vitamin E on senescent animals. The study was carried out on male New Zeland rabbits; the animals were divided into three groups; group I served as adult rabbits (6 months age, weighing 4 ± 0.5 kg), group II: aged rabbits (24 month age, weighing 7.5 ± 0.5 kg) and group III aged animals supplemented daily with the curative dose of vitamin E orally at 10 mg/kg b.w/day for 60 days. Histological study of the adult cardiac muscle revealed normal branched cardiomyocytes and normal striations with normal oval centrally located nuclei. The aged rabbits showed changes in the cardiac muscle structure that represented as disorganization of the cardiomyocytes with pyknotic nuclei, necrotic areas in the degenerated muscle fibers, congestion and dilatation of blood vessels. By IHC study, the cardiac muscle of adult rabbits expressed moderate normal desmin immunostain in the intercalated discs and Z-lines of myofibres, and moderate normal vimentin immunostain in the connective tissue and periphery to blood vessels in endomysium between cardiac myocytes. The aged rabbit's cardiac muscle expressed an intense immunopositive reaction to both desmin and vimentin. Administrative curative dose of vitamin E as anti-aging medication, antagonize the deleterious effects of aging and improved the architecture of cardiac muscle that have been confirmed through the histological and IHC investigations in the present study.
Key words: Cardiac muscle, Aging, Vitamin E, Histology, Immunohistochemistry, Intermediate Filaments, Desmin, Vimentin
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