الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 177 |  |  |
| | | from | 177 | | |
Abstract
No doubt that the close link between the thyroid gland and the cardiovascular system was clear in the earliest descriptions of thyroid dysfunction. Changes in thyroid status exert marked influences on the contractile and electrophysiological function of the heart and blood vessels. The molecular basis of such cardiovascular function alterations caused by altered thyroid hormone status has not been completely explored. The aim of the present investigation was to evaluate and confirm the effects of hyper- and hypothyroidism on cardiovascular performance , The present work was designed to evaluate the degree of oxidant stress and myocardial and to nucleic acid changes namely the rate of apoptosis in rats with hypothyroidism or hyperthyroidism compared to that when they returned to an euthyroid state. Forty adult male albino rats, of local strains weighing 150-200 grams, each, were used in this investigation. Rats were caged (8 per cage) in a fully ventilated cage, with free access to water and semi-synthetic balanced diet. Animals were divided into ٥ equal groups (8 rats in each group) as following: Group I : Euthyroid control group . Group II : Hyperthyroid group. Group III: Hyperthyroid recovered group. Group IV : Hypothyroid group . Group IV : Hypothyroid recovered group Weight of rats will be measured at the start and at end of each experiment. At the end of experiments, retro-orbital blood samples were collected for estimation of FT3 (Tri-iodothyronin), FT4 (Tetra-iodothyronin), TSH (Throid stimulating hormone) , Malondialdehyde, Total antioxidant capacity and Lipid Profile . Rats were then sacrificed by cervical decapitation and heart contractility and rhythmicity was measured , aortic strips were prepared for demonstrating vascular reactivity then the heart was used for DNA extraction and determination of rate of flow of extracted myocardial DNA . In the present work, hyperthyroid rats showed significantly high serum level of FT3 ,FT4 but lower serum TSH , reduced body weight gain, augmented cadiac contractility , fastened heart rate , slightly depressed vascular reactivitywith and without endothelium, markedly elevated serum MDA but reduced serum TAC , reduced cholesterol , LDL , HDL and triglycerides , significantly higher rate of flow of DNA extracted from cardiomyocytes on gel electrophoresis , all previous findings were so when hyperthyroid rats were compared with euthyroid ones. Our work revealed that , hyperthyroid recovered rats showed significantly lower serum level of FT3 ,FT4 but higher of serum TSH , increased body weight gain, attenuated cadiac contractility , slower heart rate , slightly enhanced vascular reactivity with and without endothelium, lower serum MDA but higher serum TAC , higher cholesterol , LDL and triglycerides but HDL insignificantly higher ,significantly lower rate of flow of DNA extracted from cardiomyocytes on gel electrophoresis all previous findings were so when hyperthyroid recovered rats were compared with hyperthyroid group. All previous parameters were insignificant when compared with euthyroid group. In the present work , hypothyroid rats showed significantly lower serum level of FT3 ,FT4 but higher serum TSH , reduced body weight gain, attenuated cadiac contractility , slowed heart rate , markedly depressed vascular reactivity with and without endothelium, higher serum MDA but lower serum TAC , elevated cholesterol , LDL and triglycerides but lower HDL, significantly higher rate of flow of DNA extracted from cardiomyocytes , all previous findings were so when hypothyroid rats were compared with euthyroid ones. Our work revealed that, hypothyroid recovered rats showed significantly higher serum level of FT3 ,FT4 but lower of serum TSH , increased body weight gain , augmented cadiac contractility , faster heart rate , improved vascular reactivity with and without endothelium, lower serum MDA but higher serum TAC , lower cholesterol , LDL and triglycerides but HDL insignificantly higher , significantly lower rate of flow of DNA extracted from cardiomyocytes , all previous findings were so when hypothyroid recovered rats were compared with hypothyroid group. All previous parameters were insignificant when compared with euthyroid group.