| Summary: | 碩士 === 中國醫藥學院 === 中國藥學研究所 === 88 === Effects of Baicalein on Proliferation and Adhesion of Cultured Rat Heart Endothelial Cells
Yun-Chih Hsieh
Institute of Chinese Pharmaceutical Science China Medical College
Abstract
Baicalein, a flavonoid present in the root of Scutellaria baicalensis GEORGI, has been reported to inhibit cell proliferation in various types of cells antagonize platelet aggregation. In this study, the effect of baicalein on cell growth was examined in primary cultured rat heart endothelial cells(RHECs). We have observed that baicalein mediated the dose- and time-dependent growth arrest in primary cultured endothelial cells at both G1 and G2/M phases. 100μM baicalein treatment caused a nearly complete inhibition of cell proliferation after three to five days of incubation. Furthermore, the baicalein-mediated growth arrest accompanied by the down-regulation of the cyclin D2, cyclin A, cyclin-dependent kinase 1 (Cdk1) and cyclin-dependent kinase 2 (Cdk2) proteins and up-regulation of p15INK4B, p21CIP1/WAF1, p53 and cyclin E proteins. However, baicalein had no effect on the levels of cyclins D1, D3, A or B, or on Cdk3, Cdk4, p16INK4A, p27KIP1, pRb1 proteins in rat endothelial cells. Evaluation of the kinase activity of cyclin-Cdk complexes showed that baicalein decreases Cdk1, Cdk2, cyclin D2 and cyclin A protein expression in rat endothelial cells and results to the markely reduced Cdk/cyclin-associated kinase activities. These results suggest that reduction of Cdk1, Cdk2, cyclin D2 and cyclin A proteins expression could prevent the entry into the S-phase in baicalein-treated endothelial cells. In addition, baicalein induced the reorganization of cytoskeletal actin and decreased the migration activity of RHECs. Furthermore, in functional studies, pretreatment of baicalein induced the adhesion of RHECs to vitronectin and increased the capillary-like tube formation on Matrigel. In conclusion, baicalein inhibits the cell proliferation and migration of RHECs in culture, whereas induces angiogenesis in vitro.
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