The effect of arginine on the activity and compartmentalization of lysosomal cysteine proteinases of parenchymatous organs in oxidative stress on the background of experimental hyperhomocysteinemia

Aim. Evaluation of the effect of arginine on the activity and intracellular distribution of cathepsins B, L, H in liver, kidney and lung tissue in experimental hyperhomocysteinemia and developing on its background oxidative damage of proteins.

Materials and Methods. Hyperhomocysteinemia in male rats of the Wistar line was formed by daily oral administration of a suspension of methionine at a dose of 1.5 g/kg 2 times a day for 21 days, to study the action of arginine the substance was used orally from 12 to 21 days of methionine administration at a dose of 500 mg/kg. In tissue homogenates measurements were carried out in cytoplasmic and lysosomal fractions. The state of oxidative modification of proteins was evaluated by analysis of the absorption spectrum of carbonyl derivatives, the activity of cathepsins B, L, H was determined by spectrofluorometric method, the activity of acid phosphatase – by the unified method «at the end point».

Results. In the cytoplasmic (nonsedimentary) fraction of the liver and kidney reduced activity of cathepsin L (in both tissues), cathepsin B (in the kidney), cathepsin H (in the liver) was found on the background of the increase in the products of proteins oxidative modification in experimental hyperhomocysteinemia. The introduction of arginine in experimental hyperhomocysteinemia completely eliminated the manifestations of oxidative damage of proteins, partially correcting the activity of enzymes: there was an increase in the activity in non sedimentary (cytoplasmic) fraction due to intracellular redistribution of enzymes. There is found inverse correlation between the content of oxidative carbonylation products of proteins and the activity of cathepsins in the non sedimentary fraction, as well as the proportion of their non sedimentary activity.

Conclusions. 1. Arginine at a dose of 500 mg/kg at a 10day administration completely corrects the increase in the products of oxidative protein carbonylation that develops in experimental hyperhomocysteinemia. 2. Under the influence of arginine there is an increase in the reduced due to isolated hyperhomocysteinemia activity of cathepsins B, L, H in the cytoplasmic fraction of the liver and kidney due to intracellular redistribution of enzymes. 3. Arginine administration causes nonselective increase of the lysosomal membrane permeability, and as a result, changes in the compartmentalization of lysosomal cysteine proteases. 4. The inverse correlation of the level of protein oxidative modification products with the activity of cathepsins in cytoplasmic (nonsedimentary) fractions, and the proportions of their nonsedimentary activity, suggesting the presence of contribution of changes in the compartmentalization of lysosomal cysteine proteinases in developing under the action of arginine compensation of oxidative stress in experimental hyperhomocysteinemia.