Search

The aim of the study was to evaluate the possibility to reduce the doxorubicin toxic effects by its immobilization with N-stearoylethanolamine (NSE) on nanocarier polyethylene glycol. The studied parameters of the doxorubicin toxicity were: the level of creatinine in the mice blood plasma and activity of alanine aminotransferase and aspartate aminotransferase in the blood plasma of mice. The activity of catalase superoxide dismutase, glutathione peroxidase and intensity of lipid peroxidation was determined in the tissues of the heart, kidneys and liver. Doxorubicin in the content of nanocarrier alone caused an increase of serum creatinine and aspartateaminotrasferase activity in plasma of experimental animals with carcinoma. Nanocomposite which contained doxorubicin and NSE, did not cause an increase of these parameters. It has been shown that the administration of a carrier containing doxorubicin to mice with Lewis lung carcinoma caused the decrease of catalase activity in mice with carcinoma. The combination of NSE and doxorubicin on the carrier led to the normalization of this parameter to the level of intact animals. NSE immobilized on a carrier together with doxorubicin caused a decrease in the activity of superoxide dismutase in the kidney tissue of mice with tumor. The tumor growth caused the increase of the of superoxide dismutase in mice. The administration of a carrier which contained doxorubicin and NSE normalized superoxide dismutase in heart tissue contrary of kidney. The obtained results show the antitoxic and antioxidant effects of N-stearoylethanolamine immobilized in the nanocarrier complex together with doxorubicin.

The intensity of the lipid peroxydation (LPO) and the antioxidant enzyme activity (gluthathione peroxydase, superoxide dismutase and catalase) after monoiodacetate injection (10 mg/ kg) within 3, 7 and 14 days was examined in the arterial and venous walls of rabbits. The increase in the amount of the intermediate and final LPO products, and also the reduction in the antioxidant enzymes activity has been found in the vessels of all types. The changes in the studied parameters were more expressed in the venous vessels, than in the arteries. It is supposed that the activation of LPO is caused by the primary depression of antioxidant systems which arises as the consequence of the disorders of energy exchange in the vascular wall under the influence of monoiodacetate.

Changes of the activity of catalase and glucose-6-phosphate dehydrogenase (G6PDH) during 48 hrs after intraperitoneal injection of 1.0, 0.5 and 0.1 mg aminotriazole per gram of body weight of two frog species as well as catalase inhibition by aminotriazole in vitro were investigated. Both aminotriazole concentration and species affiliation affected the catalase inhibition. The sensitivity of catalase from different tissues was decreased in the order: liver--kidney--lung--muscle--brain. The constant of half inhibition of lung catalase was significantly lower than that of liver and kidney catalase. The activity of G6PDH of AMT-treated frogs R. esculenta was higher comparing to control group. Possible ways of compensation of antioxidant defense under catalase inhibition are discussed.

In the previous work we have found two peaks of catalase activity at acid and neutral pH in partially destroyed bacteria E. coli K12 KS400. The present study indicates that catalase activity with two pH-optimums is sensitive to pH of cultivation medium. The relative catalase activity of frozen-thawed bacteria preparations measured at pH 3.5 increased two-fold and activity measured at pH 7.0 didn't change by shift of medium pH from value 5.5 to 7.0. In analogical preparations of bacteria grown in slightly alkaline media activity with acid maximum was not observed, but activity with neutral maximum rose to 130% in comparison with the intact cells was revealed. Two peaks of activity differed in their sensitivity to bacteria destruction, heating, inhibition by NaN3 and AMT, oxidative stress. The analysis of recent literature information and experimental data leads us to conclude that the activity with neutral pH-optimum consists of two known catalase forms HPI and HPII in E. coli. The ratio of HPI and HPII is 70 and 30%, respectively what was concluded from inhibition of catalase activity with neutral pH-optimum by AMT. Properties of catalase activity with acid pH-optimum didn't corresponding to any known enzyme forms. It is suggested the activity measured at pH 3.5 is results of some unstable activator which acts in acid pH range. It is possible that the described activity with acid pH-optimum is specific for the used E. coli strain. Investigation of another strain of E. coli K12 AB1157 confirmed this idea where the activity peak with acid pH-optimum was not detected.

The possibility for investigation of catalase (CAT) activity under the conditions of intact E. coli cells was estimated. This approach is based on the possibility of hydrogen peroxide freely cross biological membranes. CAT activity of native cells had a broad maximum between pH values 4.5 and 7.5. Desintegration of cells by freezing--thawing and ultrasonication indicated that there were two CAT activity peaks at pH values about 3.5 and 7.0. Activity of CAT with acid pH-optimum decreased at cell desintegration, but one with neutral pH-optimum was rather stable under this procedure. The enzyme in native conditions was less sensitive to the inhibition by high concentrations of hydrogen peroxide than its counterpart from destroyed cells. Activity of CAT in native and desintegrated cell preparations had different sensitivity to heating and inhibition by reduced glutathione, but it was inhibited by azide similarly. Difference in the CAT properties of native and desintegrated bacteria preparations may be explained by different possibility to penetrate cell membrane by reagents and/or by possible modification of the enzyme properties at destruction of native microenvironment.