Ultrasound biomicroscopy validation of a murine model of cardiac hypertrophic preconditioning: comparison with a hemodynamic assessment

In mice, myocardial hypertrophic preconditioning (HP), which is produced by the removal of short-term transverse aortic constriction (TAC), was recently reported to render the heart resistant to hypertrophic responses induced by subsequent reconstriction (Re-TAC). However, there is no efficient noninvasive method for ensuring that the repeated aortic manipulations were successfully performed. We previously demonstrated that ultrasound biomicroscopy (UBM) is a noninvasive and effective approach for predicting TAC success. Here, we investigated the value of UBM for serial predictions of load conditions in establishing a murine HP model. C57BL/6J mice were subjected to a sham operation, TAC, or Re-TAC, and the peak flow velocity at the aortic banding site (PVb) was measured by UBM. Left ventricular end-systolic pressure (LVESP) was examined by micromanometric catheterization. The PVb was positively associated with LVESP (R2 = 0.8204, P < 0.001, for TAC at 3 days and R2 = 0.7746, P < 0.001, for Re-TAC at 4 wk). PVb and LVESP values were markedly elevated after aortic banding, became attenuated to the sham-operated level after debanding, and increased after aortic rebanding. The cardiac hypertrophic responses were examined by UBM, histology, RT-PCR, and Western blot analysis. Four weeks after the last operation, with PVb ≥ 3.5 m/s as an indicator of successful aortic constriction, Re-TAC mice showed less cardiac hypertrophy, fetal gene expression, and ERK1/2 activation th...

Source: AJP: Heart and Circulatory Physiology - July 1, 2017 Category: Cardiology Authors: Huang, J., Wu, J., Wang, S., You, J., Ye, Y., Ding, Z., Yang, F., Wang, X., Guo, J., Ma, L., Yuan, J., Shen, Y., Yang, X., Sun, A., Jiang, H., Bu, L., Backx, P. H., Ge, J., Zou, Y. Tags: RESEARCH ARTICLE Source Type: research