Sappan Lignum Extract Inhibits Restenosis in the Injured Artery through the Deactivation of Nuclear Factor-κB

Abstract

The aim of the study was to explore whether Sappan Lignum Extract (SLE) would inhibit vascular restenosis in injured artery and its inhibitory mechanism by using a balloon-injured rat carotid artery restenosis model. Different doses of SLE were administered to the rats by tube feeding, starting from four days before surgery and continuing twice per day for two weeks after carotid injury. Injured carotid arteries isolated from rats were embedded in paraffin block and tissue sections were stained with H&E to assess restenosis. The Effects of SLE on vascular restenosis, which are involved in smooth muscle cell cycle, NF-κB p65 expression, and Superoxide (O2-) production, was assessed by RT-PCR, western blot assay, and immunohistochemistry. The results showed that in a rat carotid model of balloon dilatation injury, SLE significantly reduced the intimal-to-medial area ratio and vascular restenosis after 14 days of the injury. Immunohistochemistry study revealed no inhibited PCNA expression caused by SLE. Rat serum containing Sappan Lignum (RSC) was found neither anti-proliferative effect in cultured vascular smooth muscle cells (VSMCs) and nor arrest cell cycle progress detected by flow cytometry. RSC remarkably decreased the expression of TNF-α mRNA and protein in cultured VSMCs. Electrophoretic mobility shift assay proved that RSC inhibited the binding of NF-κB to specific DNA sequences in TNF-α treated VSMCs. Western blot pronounced that RSC and N-acetyl-L-cysteine (NAC) reduced expression of NF-κB p65 in nuclear extracts in TNF-α treated VSMCs. RSC and NAC also attenuated superoxide anion generation in TNF-α treated VSMCs. In summary, the inhibitory effects of SLE on vascular restenosis may not be mediated through inhibiting vascular cell proliferation, but through inhibiting vascular inflammation instead, which may be attributed to the inhibition of TNF-α and subsequent deactivation of NF-κB, which was in part mediated through inhibiting superoxide anion generation.

Keywords

• Sappan Lignum Extract (PubChem CID: 441975)
• Vascular Restenosis
• TNF-α
• NF-κB
• Rat Carotid Model