RESUMO
<p><b>OBJECTIVE</b>To study the effect of Scutellaria baicalensis stem-leaf total flavonoids (SSTF) on cardiocyte apoptosis of neonatal rats induced by hypoxia/reoxygenation and its action of mechanism. METHODS Sixty one to two days old rats, male or female, were selected. Hypoxia/reoxygenation injured model was established in cultured cardiocytes of neonate rats. The cultured neonatal rat cardiocytes were divided into 5 groups, i.e., the normal control group, the hypoxia/reoxygenation injury group (as the model group, cultured cardiocytes were exposed to hypoxia 2 h and subsequently reoxygenated for 4 h), the hypoxia/reoxygenation injury plus 50 mg/L SSTF group (as the low dose SSTF group), the hypoxia/reoxygenation plus 100 mg/L SSTF group (as the middle dose SSTF group), and the hypoxia/reoxygenation plus 200 mg/L SSTF group (as the high dose SSTF group). The cell viability was detected by methyl thiazolyl tetrazolium (MTT) colorimetry. The apoptosis of cardiocytes was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and the apoptosis rate calculated. The Bcl-2 and Bax protein expressions were determined by immunohistochemistry.</p><p><b>RESULTS</b>Compared with the normal control group, the cell viability, Bcl-2 protein contents and Bcl-2/Bax decreased, the apoptosis rate and Bax protein contents increased in the model group (all P<0.01). Compared with the model group, the cell viability, Bcl-2 protein contents and Bcl-2/Bax increased, while the apoptosis rate and Bax protein contents decreased in each SSTF treated group (P<0.05, P<0.01). Compared with the low dose SSTF group, significant difference existed in each index of the high dose SSTF group (all P<0.05).</p><p><b>CONCLUSIONS</b>SSTF had protection on hypoxia/reoxygenation induced cardiocyte apoptosis. Its protective mechanism might be correlated with its up-regulation of the expression of Bcl-2 protein ahd down-regulation of the expression of Bax protein.</p>