Nelumbo nucifera leaf extract inhibits neointimal hyperplasia through modulation of smooth muscle cell proliferation...

Endovascular injury induced by balloon withdrawal leads to the increased activation of matrix metalloproteinases (MMPs) in the vascular wall allowing the proliferated smooth muscle cells (SMCs) to digest the surrounding extracellular matrix and migrate from the media into the intima leading to the intimal thickening. The objective of this study was to examine the effect of Nelumbo nucifera leaf extract (NL) on intimal thickening of rat carotid artery injured by balloon catheter and on the proliferation and migration of cultured vascular smooth muscle cells (VSMCs) induced by tumor necrosis factor-α.

NL was administered orally using gastric sonde at three different doses, 100 mg kg(-1) (NL100), 400 mg kg(-1) (NL400), and 800 mg kg(-1) (NL800) for 4 wk from the day of balloon injury in the rats. VSMC proliferation and migration were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Boyden chamber methods, whereas enzymatic action of matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9) was carried out by gelatin zymography, and MMP-9 protein expression, extracellular signal-regulated kinase 1/2, and c-Jun N-terminal kinase phosphorylations were assessed by Western blot analyses.

NL reduced the intimal thickening by suppressing VSMC's proliferation through inhibition of extracellular signal-regulated kinase 1/2 phosphorylation and their migration by reducing the expression of MMP-2 and -9 through inhibition of JNK1/2 phosphorylation.

Thus, the results suggest that NL can be considered of therapeutic value in the prevention of atherosclerosis because restenosis after percutaneous transluminal coronary angioplasty can be considered a model of "accelerated atherosclerosis."