RESUMO
AIM OF THE STUDY: To evaluate the protective effect of baicalein on myocardial dysfunction caused by endotoxaemia in rats and to explore the possible mechanisms. MATERIALS AND METHODS: Baicalein (10mg/kg, intravenous) was administered to conscious Wistar rats 30min after lipopolysaccharide (LPS; 10mg/kg, intravenous) challenge. Six hours after LPS administration, the contractile function of the isolated heart was examined using the Langendorff technique. Cardiac protein expression related to inflammatory responses, superoxide anion production and caspase-3 activity were measured. RESULTS: Post-treatment with baicalein significantly attenuated the LPS-induced hypotension with accompanying tachycardia. The contractile function of isolated heart was significantly preserved 6h after LPS administration, following treatment with baicalein. Furthermore, baicalein induced the expression of heme oxygenase-1 protein and reduced superoxide anion formation in the myocardium of LPS-treated rats. Cardiac levels of inducible nitric oxide synthase, monocyte chemoattractant protein-1, phospho-IκBα and phospho-p65 protein and caspase-3 activity significantly increased 6h after LPS challenge but baicalein significantly attenuated these LPS-induced changes. CONCLUSIONS: Baicalein improves myocardial contractility in LPS-induced sepsis, which may be related to reductions in oxidative stress, myocardial inflammatory responses and apoptosis.