The expression of iNOS and eNOS during arteriogenesis induced by femoral artery ligation in rabbit

Objective:To investigate the expression of inducible nitric oxide synthase(iNOS)and endothelial nitric oxide synthase(eNOS)in collateral vessels of rabbit hindlimb induced by femoral artery ligation.Methods:Acute femoral artery ligation was performed in 12 adult New Zealand white rabbits with two knots.The contralateral side was used as the controls.The animals were sacrificed after surviving for one week.Expression of iNOS and eNOS in the collateral vessels were detected by immunofluorescence with specific antibodies against iNOS and eNOS.The results were viewed and photoed with Leica laser confocal microscope.The data were processed with silicon graphics octane system.Results:In normal small arterial vessels,expression of iNOS was very low,but it was significantly increased in growing collateral vessels,2.8 times higher over that in controls.Increased iNOS was seen in all layers of the vascular wall.The pattern of expression of eNOS was simmilar to that in iNOS.It was 2.2 times higher in growing collateral vessels than that in controls.Expression of eNOS was predominately distributed in endothelial cells.Conclusions:We for the first time demonstrate that expression of iNOS is increased during arteriogenesis induced ligation of femoral artery in rabbit hind-limbs.The increased expression of iNOS and eNOS may play an important role in collateral vessels growth by mediating endothelial cell proliferation,migration and formation of inflammation.