Ultrasound-Guided Percutaneous Puncture to Establish a Rat Model of Mitral Regurgitation: A Non-Thoracotomy Approach.

Mitral regurgitation (MR) is a significant risk factor for heart failure, yet existing rodent models face limitations in invasiveness and reproducibility. This study established a novel percutaneous, ultrasound-guided rat model of MR to overcome these constraints. Thirty male Sprague-Dawley rats underwent echocardiography-guided mitral valve injury, allocated to severe MR (40-70% regurgitation), massive MR (> 70%), or sham groups. Serial echocardiographic assessments were performed at baseline, 30 min, and 2, 4, and 8 weeks post-procedure, with histological validation of myocardial fibrosis. The technique achieved 100% success with no acute mortality and enabled precise titration of regurgitation severity. Both MR groups exhibited progressive, body size-independent cardiac remodeling. Speckle-tracking revealed basal-segment-predominant longitudinal strain reduction, correlating with histologically confirmed peri-annular fibrosis. Survival was significantly lower in massive MR (40% vs. 90%, p = 0.006). This minimally invasive model reliably replicates human MR pathophysiology with high reproducibility and precise severity control, providing a robust platform for mechanistic investigation.