A Experimental Study: Losartan Regressed Changes Of Intercalated Discs Of Rat's Hearts Induced By Pressure-overload

Intercalated discs of heart ,which is mainly composited of fascia adhesion(FAH),desmosome(DES),and gap junction, are joints between cardiac myocytes.It is the anatomical basis of electra conduction,constriction,and metabolism in myocardiuni.Many studies have showed the structure and its componet of intercalated discs in hypertrophy hearts induced by pressure-overload are changed,and this might be one of the pathological basis of left ventricular remodeling,resulting dysfunction of constriction , diastole ,and arrhythmia.lt is clinical significance to redress the abnomal inrecalated discs of hearts.ACEI can correct the myocardial hypertrophy indued by bight blood pressure,and ameliorate the prognosis of patients. ARB can directly block the function of angiotensin II .So we guess ARB can not only redress the myocardial hypertrophy in hypertension ,but also correct the anomalies of intercalated discs.Objection:To prove losartan to regress changes of intercalated discs of rat's hearts induced by pressure-overload .Methods and result:1.30 Wistar male rats with body weight 186 + 25g were subjected to three groups(each group n=10): fake operation group,operation group and operation +losartan group(treatment group).The model of rat abdominal aortic constriction was adopted in operation and treatment group.The rats of fake operation group received the same procedure except the abdominal aortic constriction.Three groups were fed on normal diet during the first ten weeks after procedure,and within the second ten weeks ,fake operation and operation groups were fed on normal diet continuously,but the treatment groups were fed on normal diet and losartan.2.There were on difference between operation and treatment group in the thickness of left ventricular posterior wall and weight index of left ventricle after tenth weeks of operation,and they all have significant increase compared with fake group(P<0.05 respectively).At the 20th weeks after procedure,the thickness of left ventricular posterior wall, weight index of left ventricle , and cardiac myocyte's area were less in treament group than those in operation group(p<0.05),and threre were no difference between treatment and fake operation group (p>0.05) .3.Expression of pan -cadherin,connexin 43 and desmoplakin in cardiac myocytes were studied by immunohistochemical technique.At the 10th week after constriction,the structure of cadherin,desmosome and gap junction in intercalated discs were destroyed ,gap of intercellular space widened in the treatment and operation group. Expression and distribution of pan-cadherin,connexin43 and desmoplakin were became less and disorderly on the cardiac myocytes.however,at the 20th week after operation ,there were no discrepancy between treatment and fake operation group in the structure of fasicia adhesion,desmosome and gap junction in intercalated discs ,and expression and distribution of pan-cadherin,connexin43 and desmoplakin(p>0.05)Conclusion:Losartan can induce regression of cardiac hypertrophy and normalization of intercalated discs of rat's hearts due to pressure-overload.