Abstract P2065: Mice Under Transverse Aortic Constriction And Treated With Sodium Oxalate May Develop Cardiac Dysfunction

Abstract

Background: Experimental models are important for studying the mechanisms of cardiovascular disease. The transverse aortic constriction model (TAC) is among the most used in the literature for the study of cardiac hypertrophy. The soluble sodium oxalate (OXA) model generates renal injury but is also associated with cardiac hypertrophy through hypertensive-like lesions. There is little information in the literature on direct hemodynamic recording in both models mentioned, as well as there is no data on the changes caused by the association of these two models. Therefore, our objective is to evaluate whether TAC associated with OXA gavage could be a new model of cardiac dysfunction. Methods and Results: Male C57BL mice were randomized as follows: SHAM animals that received gavage with vehicle or OXA solution, and animals submitted to TAC and gavage with vehicle or OXA solution. Echocardiography and metabolic cage assessment were used to quantify cardiac and renal function. Direct blood pressure (BP) recording was also performed to assess baroreflex sensitivity and histological analysis. The TAC+OXA group had the highest BP values (mean BP:SHAM:100±5.0 vs. TAC+OXA:132±4.8mmHg, p<0.01), the highest pulmonary congestion index, an increase in the double product, an important reduction in autonomic modulation (AM), heart rate variability (HRV) (SD-PI: SHAM+OXA:12.5±1.8 vs. TAC+OXA:2.8±0.2ms, p<0.01) and alpha index (SHAM:3.6±1.0 vs. TAC+OXA:0.6±0.1, p=0.04). The TAC group showed the greatest weight of the ventricles and the greatest increase in blood pressure variability (DP-SBP). The SHAM+OXA group showed an increase in AM and HRV. The three groups showed a significant reduction in reflex tachycardia. Conclusion: TAC surgery provided cardiac hypertrophy, reduction in reflex tachycardia and changes in autonomic modulation. In the absence of TAC, the treatment with OXA for 15 days increased autonomic modulation. TAC surgery in conjunction with OXA gavage caused greater cardiac dysfunction.