Effects of oxidized low density lipoprotein on the proliferation of smooth muscle cells

• Main Authors: Chi-Hong Lo, 羅志宏
• Other Authors: Ming T. Lin
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/16834125507435141970

碩士 === 國立成功大學 === 生物化學研究所 === 82 === Over the past years, numerous studies have indicated that oxidatively modified low density lipoprotein (LDL) plays a critical role in the pathogenesis of atherosclerosis. On the other hand, arterial smooth muscle cell migration and proliferation contribute to the development of atherosclerotic lesions. In the present studies we investigated the effects of oxidized LDL on the proliferation of smooth muscle cells. The effect of oxidized LDL on the growth of smooth muscle cells was assayed by the [3H]-thymidine incorporation into DNA. Results showed that smooth muscle cells were incubated with oxidized LDL that was oxidized by incubating with endothelial cells, copper ion or with combination of both, the incorporation of [3 H]- thymidine into DNA was decreased and the release of lactate dehydrogenase (LDH) into the medium was increased. But smooth muscle cells that were incubated with 10% FBS-DMEM released more LDH, suggested that the inhibitory effect on smooth muscle cells proliferation was not related to cell damage. On the other hand, incubation of cells with oxidized LDL and PDGF (10 ng/ml) resulted in a marked dose-dependent inhibition of the PDGF- induced cell proliferation. Fucoidin, the acetyl-LDL receptor inhibitor, counld not reverse the smooth muscle cells proliferation that was inhibited by oxidized LDL. Oxidized LDL counldn't block PDGF-induced signals, such as DAG formation. The results suggested that receptor-mediated signal of oxidized LDL was not a prerequisite for the inhibitory effect on smooth muscle cells proliferation. The growth signals in smooth muscle cells could not be reduced by oxidized LDL, suggested that the inhibitory effect was not related to signal transduction. Ox- LDL inhibited cell proliferation in cultured smooth muscle by undefined mechanism.