The Mechanism Of Inhibiting Vascular Restenosis With Low Molecular Weight Chitosan

Objective To study the mechanism of low molecular weight chitosan(LMCTS) on the rat abdominal aorta vascular restenosis, and to provide effectiveand non-toxic candidates for the clinical treatment of vascular diseases such asrestenosis.Methods The study was performed on rat stenosis model of balloon injury inabdominal intima of aorta. The experimental animals were divided into two groups:7d group and14d group, while each group was subdivided into four subgroups,namely the control group, model group, chitosan group1(100mg/kg) and chitosangroup2(200mg/kg). The rats were given injection through caudal vein once daily.With immunohistochemical method and western-blot, LMCTS’ influences on TNF-αexpression in rat abdominal aorta vascular restenosis were observed on7d and14d,respectively. Abdominal aorta vascular smooth muscle cells (VSMCs) were givenprimary culture, and then detected through the following methods: cell countingkit-8(CCK8): for the influences of LMCTS on VSMCs proliferation induced byTNF-α at48h,72h, and96h; cell adhesion assay: for the influences of LMCTS(100μg/mL,200μg/mL,500μg/mL) on adhesions of monocyte and VSMCs inducedby TNF-α; ELISA: for the influences of LMCTS (100μg/mL,200μg/mL,500μg/mL)on ICAM-1in VSMCs induced by TNF-α at48h,72h, and96h; Western-Blot: forthe influences of LMCTS (100μg/mL,200μg/mL,500μg/mL) at72h and96h onICAM-1induced by TNF-α (20ng/mL).Results The rat stenosis model of balloon injury in abdominal intima of aortawas established. Immunohistochemistry and western-blot showed that chitosangroups (100mg/kg and200mg/kg) can inhibit the expression of TNF-α in the bloodvessels; while from cellular level, with primarily cultured VSMCs, the experimentalresults showed that TNF-α (20ng/mL) can enhance the adhesion of monocyte andVSMCs, while its enhancement could be inhibited by LMCTS;when LMCTS were at500μg/mL, P<0.05; and the inhibition ability was especially stronger. Accordingto the results of CCK8, TNF-α (20ng/mL) can stimulate VSMCs proliferation;LMCTS (100μg/mL,200μg/mL,500μg/mL) had no obvious inhibition (P>0.05) at48h, LMCTS (500μg/mL) had inhibition (P<0.05) on TNF-α-induced (20ng/mL)VSMCs proliferation at72h, and LMCTS (200μg/mL,500μg/mL) can inhibitTNF-α-induced (20ng/mL) VSMCs proliferation at96h (P<0.05); ELISA showedthe similar results. ICAM-1treated by LMCTS showed that TNF-α (20ng/mL) canup-regulate the ICAM-1. LMCTS (100μg/mL,200μg/mL,500μg/mL)had no obviousinhibition (P>0.05) on TNF-α-induced up-regulation of ICAM-1at48h, LMCTS(500μg/mL) had inhibition (P<0.05) on TNF-α-induced (20ng/mL) ICAM-1at72h,and LMCTS (200μg/mL,500μg/mL) can inhibit TNF-α-induced (20ng/mL)ICAM-1at96h (P<0.05); when LMCTS at500μg/mL, it reached the maximuminhibition with time-dose independence; Western Blot showed that LMCTS had acertain inhibition on the TNF-α-induced expression of ICAM-1in VSMCs. Ittheoretically provides a basis for LMCTS to be applied in the prevention andtreatment of vascular restenosis.Conclusion Low molecular chitosan can inhibit the TNF-α expression inabdominal aortic vascular tissues with balloon injury, inhibit the proliferation ofvascular smooth muscle cells (VSMCs) through inhibiting their TNF-α expression,inhibit the adhesion of VSMCs through inhibiting the expression of ICAM-1inducedby VSMCs TNF-α and inhibit VSMCs proliferation and adhesion through inhibitingthe expression of TNF-α, the inflammation factor, thus preventing vascularrestenosis.