A new experimental model of chemical ablation of the Intrinsic Cardiac Nervous System reduces heart contractility and causes a type of dilated cardiopathy in rats Um modelo experimental de ablação do Sistema Nervoso Intrínseco Cardíaco reduz a contratilidade do coração de ratos

AbstractObjective: The function of Intrinsic Cardiac NervousSystem is largely unknown, as is its role in heart disease. Inthe digestive system, a topic aplication of Benzalkoniumchloride (BC) leads to intrinsic denervation of the viscera.Thus, our aim was to obtain an experimental model of cardiacintrinsic denervation by the application of BC. Method: Thirty male Wistar rats received intrapericardicinjection of CB 0.3% (CB animals) and thirty similar animalsreceived saline (C animals). After 15 days the animals weredivided in three groups, with 10 CB-treated and 10 saline-treated animals each. Group I was submitted to radiologicaland morphologic studies. The cardiac shadow area (CSA)and cardiothoracic index were calculated in roentgenogramswith a semi-automatic image analysis system (MINI-MOP).The day after the animals were weighted and sacrificed withheart, liver and lung collected for histopathologic analysis.The animals of group II were submitted to a hemodynamicstudy. Measurements of blood pressure, heart rate and cardiacoutput were performed using the Cardiomax II termodilutionsystem and a Termistor sensor. With the animals of thegroup III, the integrity of extrinsic parassympatic cardiacinnervartion was examined by measuring heart rate responseto electrical stimulation of the right vagus. Electrical activitywas assessed by ECG.