Triptolide protects rat heart against pressure overload-induced cardiac fibrosis

Abstract

Emerging evidence underlines the role of inflammation activation in the process of cardiac fibrosis. Triptolide has potent anti-inflammatory and anti-proliferative properties, and extensively used in the treatment of chronic inflammatory disorders. In the current study, we test the hypothesis that triptolide treatment facilitates to attenuate chronic pressure overload-induced cardiac fibrosis in a model of rat. Adult male Sprague-Dawley rats were subjected to a suprarenal abdominal aorta constriction (AC) or sham (as control) to induce sustained pressure overload. Eight weeks later, rats were randomly assigned to receive triptolide (9 μg/kg.d, i.p) or vehicle (0.1% dimethyl sulfoxide, 0.2 ml/d, i.p) treatment for an additional 8 weeks. AC caused significant pathological hypertrophy, cardiac fibrosis and reduced cardiac diastolic function. Triptolide treatment markedly inhibited AC-induced increases in myocardial collagen volume fraction, collagen type I/III deposition, left ventricular end-diastolic pressure, expressions of pro-fibrogenic factors (transforming growth factor-β and angiotensin II) and pro-inflammatory cytokines (IL-1β and IL-6), NF-κB activation and inflammatory cell infiltration in left ventricles compared with vehicle, without affecting cardiac hypertrophy. However, triptolide had no effects on systemic blood pressure and circulating angiotensin II level. Collectively, the findings suggested that triptolide treatment elicits favorable anti-fibrogenic effect in a blood pressure-independent manner, at least in part, through inhibiting myocardial pro-fibrogenic factor production and inflammatory activation in the pressure overloaded heart.