Effect Of Thyroid Hormone On The Expression And Distribution Of Cx43 In Atriums Of Canine

Objective: To study the effect of thyroid hormone on the expression and distribution of Cx43 in canine hyperthyroid cardiomyopathy induced by Levothyroxine and to investigate the relationship between the remodeling of Cx43 and atrial tachyarrhythmia.Methods: A canine model of hyperthyroidism was established by daily intraperitoneal injection of L-thy (80ug/Kg per day, 8 months). Eleven adult canines were randomly divided into two groups: control group (n=6), L-thy group (n=5). At 2 months interval, heart rate, body weight and AERP were assessed in both groups, and serum TT3 and TT4 were measured with Radioimmunoassays(RIAs). At the beginning and the end of the observational period, all the canines underwent echocardiography and IVS, LVD, LAD, LVPW thickness were measured. Atrial tissues were collected at the 8th month. Myocardium structure changes were detected by HE stain in light microscope. Expression of Cx43 in atria was evaluated with western blot analysis. Cx43 in atria was located by immunofluorescence and detected with Laser Scanning Confocal Microscope.Results: Compared with control group, L-thy group canines displayed changed life habits, increased heart rate, decreased body weight, thickened LVPW and IVS, decreased LVD. Histological studies showed myocardial hypertrophy, myocardial fibers disruption, decreased atrial myocyte,...