Influence of L-Nω-nitroarginine methyl ester and sodium nitroprusside in vitro on the oxidative modification of rat lysosome proteins

Aim. To investigate in vitro effects of 5 mM L-Nω-nitroarginine methyl ester and 0.1 mM sodium nitroprusside on oxidative modification of lysosomal proteins of liver of intact sexually mature female rats of Wistar line. Methods. In the control groups in vitro incubation of isolated lysosomes in the isolation medium for 1, 2 and 4 hours was carried out. Experimental groups were incubated similarly in solutions of 5 mM L-Nω-nitroarginine methyl ester and 0.1 mM sodium nitroprusside. Protein oxidative modification was measured in sedimentary fraction according to R.L. Levine’s method in E.E. Dubinina’s modification. Reserve-adaptive capacity was calculated as the difference between total area under the curve of carbonyl derived proteins after metal-catalyzed oxidation (taken as 100%) and spontaneous oxidation, expressed as a percentage. Results. After 4-hour in vitro incubation 5 mM L-Nω-nitroarginine methyl ester was found to statically significantly increase the total level of protein oxidative modification compared to the control group by 2.41 times and to reduce reserve-adaptive capacity by 4.96 times, and 0.1 mM sodium nitroprusside increases the total level of protein oxidative modification compared to the control group by 2.05 times and reduces reserve-adaptive capacity by 1.56 times. One of the possible mechanisms of this phenomenon may be the reduced activity of lysosomal proteinases. 2-hour and 4-hour in vitro incubation of lysosomes in 5 mM L-Nω-nitroarginine methyl ester is accompanied by an increase of secondary markers of the ratio of protein oxidative modification relatively to 1-hour exposure by 1.18 times and 1.35 times, respectively. At 1-hour in vitro incubation in 0.1 mM sodium nitroprusside, increase of secondary markers of protein oxidative degradation by 1.64 times occurs. Conclusion. The in vitro effect of 5 mM -Nω-nitroarginine methyl ester and 0.1 mM sodium nitroprusside results in visible changes of oxidative modification of rat liver lysosomal proteins.

oxidative protein modification, lysosomes, reserve-adaptive capacity, experiment