A novel model of constrictive pericarditis associated with myocardial fibrosis in rats

Abstract

An efficient animal model is fundamental for studies on the underlying mechanisms of constrictive pericarditis (CP). A novel CP rat model was established by pericardial injection composing of lipopolysaccharides (LPS) and talcum powder without thoracotomy. Pathological changes were confirmed by histological staining. E‐flow Doppler of mitral valve, tissue Doppler E′ in the medial mitral annular (E′sep) and the lateral mitral annular (E′lat) were measured to assess ventricular filling function. Circumferential, longitudinal, and radial strains (SC, SL and SR) and the respective strain rates (SrC, SrL and SrR) were analyzed in interventricular septum (IVS) and left ventricular free wall (LVFW). Rat cardiac fibroblasts (CFs) were treated with LPS. The activation of transforming growth factor β1 (TGF‐β1) was confirmed by Q‐PCR and western blot assays. Thickening of pericardium and fibrosis in pericardium and subepicardial myocardium were showed in the model group. Diastolic dysfunction in the CP group was indicated by decreased E′lat and E′lat/E′sep, increased E/E′lat, decreased EFW of SrC and SrL, increased AIVS and decreased E/A of SrC, SrL and SrR. Systolic dysfunction was indicated by decreased SCFW and SLFW in CP rats. The levels of TGF‐β1, p‐Smad2/3, α‐smooth muscle actin (α‐SMA), and collagen‐I/III (COL‐I/III) were increased in the CP group. The increased TGF‐β1 that induced by LPS activated and phosphorylated Smad2/3 resulting in the secretion of α‐SMA and COL‐I/III. This model is of vital importance in studying the pathogenesis of CP.

Annulus Reversus Caused by Transmural Scar in a Patient With Myopericarditis

“… 6 A recent animal study confirmed the presence of myocardial fibrosis in an experimental model aimed to primarily induce pericardial constriction. 7 Moreover, myocardial dysfunction appears to play an important role in the pathophysiology of constrictive pericarditis, mainly due to subepicardial involvement of the pericardial process and localized myocardial ischemia, in the setting of high transmural pressures and impairment of coronary blood flow. 8 Since the ventricular apex remains relatively stationary throughout the cardiac cycle, mitral annular assessment allows for measurement of overall longitudinal LV function.…”