An Alternative Technique for Heart Lesion in the Rat: A Step to Fetal Heart Implantation for Cardiac Tissue Repair Running Title: A New Technique of Heart Lesion in Rat

Existing experimental models of cardiac lesion do not allow precise reproducible dimensions of injury with complete safeness of surrounding tissues and cannot answer the tremendous question for heart cell therapy: are the implanted cells unable to influence the heart healing process or do the conditions in the injured heart prevent their complete development and integration?60 rats were used for elaborating an alternative technique of cardiac lesion.The anterior apical area of the heart was cauterized with a «Cautery high temperature fine tip» to create an injury of controllable, precise and reproducible dimensions (8×8 mm² surface, 1 mm depth).To evaluate functional and morphological characteristics of the lesion, electrocardiography, pulse oximetry, echocardiography and optic microscopy were performed at different times (from day 0 to 230) after the operation.After technical adjustment a 100% survival of the last 15 operated animals was obtained. A sub epicardium “infarction” was documented: ECG mirror ST-modifications in 2 leads, stable ejection fraction significant decrease, necrotic alterations and fibrosis of the lesion area, with surrounding myocardium preserved.The survival and the injury evolution suggest that the proposed technique could be used for studies concerning cardiac tissue repair.