A novel anti-fibrotic agent, baicalein, for the treatment of myocardial fibrosis in spontaneously hypertensive rats

Myocardial interstitial fibrosis causes left ventricular stiffness and diastolic dysfunction. Despite its clinical significance, treatment options are limited. The flavonoid baicalein, extracted from roots of a Chinese medicinal plant, Scutellaria baicalensis Georgi was shown to inhibit liver fibrosis. This study sought to investigate whether chronic treatment with baicalein could attenuate myocardial fibrosis in spontaneously hypertensive rats (SHR). SHR were treated daily with baicalein while the control group received vehicle. At the end of study, SHR control group developed significant myocardial fibrosis that was attenuated by baicalein treatment for 4 and 12 weeks. Rats treated with baicalein were protected against an increase in heart to body weight ratio, plasma level of brain natriuretic peptides, intraventricular septum thickness, myocardial collagen volume of left ventricle (all P < 0.05, respectively). The antifibrotic effects of baicalein were further illustrated by the suppressed expression of left ventricle pro-collagens I and III accompanied by the decreased expression of 12-lipoxygenase, and by reduced expression and activity of matrix metallopeptidase 9 and extracellular signal-regulated kinases. The present results show for the first time that baicalein can inhibit cardiac fibrosis in hypertensive rats.