A.V. Vavaev, E.G. Tischenko, V.P. Mokh, A.V. Maksimenko
Changes in aortic rat ring tone were studied in vitro after addition of varied concentration of hydrogen peroxide and superoxide dismutase (SOD), catalase (CAT) or SOD-chondroitin sulfat-CAT (SOD-CHS-CAT), which were added 10 min before H2O2 at the background of noradrenalin (NA) preconstriction. The concentration-dependent effect of the arterial segment (at 0,01 – 1,0 mM H2O2) caused a constriction, which was superseded by dilatation (at concentration higher than 0,1 mM). High concentration of H2O2 caused irreversible disturbances of vascular activity. 1mM H2O2 was significantly reduced further contractile NA-effect even after multifold wash. Native CAT or SOD-CHS-CAT (at the same enzyme activity concentration) eliminated dose-dependently the effect of H2O2 and promoted preserving of second NA-response. The SOD-CHS-CAT (at 500 E/ml) was more effective than CAT. This effect could relate with experimental proved effect of SOD being part of SOD-CHS-CAT. At the similar conditions native SOD and SOD-CHS-CAT induced the vascular dilatation on 20% due to the increase of NO-bioavailability. SOD-CHS-CAT conjugate possessed in the sum by effects of SOD and CAT simultaneously. This is important for combined antioxidant protection against oxidative stress in vascular.