ABSTRACT
To study the anti-proliferation effect of lambda-carrageenan oligosaccharides (lambda-CO) on human umbilical vein endothelial cells (HUVECs) and expression of apoptotic relevant genes, the influence of lambda-CO on HUVECs proliferation was measured by MTT assay; apoptotic rate, cell cycle distribution and the level of active caspase-3 of HUVECs were analyzed using flow cytometry; the mRNA level of apoptosis related genes was determined by RT-PCR. At a high concentration of 1 mg x mL(-1), lambda-CO significantly inhibited the endothelial cell proliferation. Annexin-V FITC/PI double stain assay showed that when treated with 0, 0.8, 1 mg x mL(-1) of lambda-CO for 24 h, cell apoptotic rates were (1.67 +/- 1.6)%, (11.48 +/- 2.4)% and (13.81 +/- 2.2)%, respectively, when treated for 48 h, cell apoptotic rates were (2.02 +/- 2.3)%, (13.84 +/- 1.9)% and (38.72 +/- 2.5)%, respectively, cell cycle assay showed the decrease of cells in G0/G1 phase, and increase in S phase. Furthermore, we observed the level of active caspase-3 increased in a dose-dependent manner at 24 th and 48 th. RT-PCR results indicated that mRNA of TNFalpha, p53, caspase-8 and caspase-3 in cells increased after treated with lambda-CO. lambda-CO induce apoptosis of HUVECs in a dose-dependent way and arrests cells at S phase, which mainly due to the up-regulation of apoptotic genes such as TNFalpha, p53, caspase-8, caspase-3 and increase the level of active caspase-3.