[The role of genetic peculiarityes (of organisms) in the resistance to neoplastic processes in August line and Wistar population rats].

The probability of development of the Ehrlich's ascites carcinoma in young August and Wistar rats was investigated. The Ehrlich's carcinoma strain was derived in mice in the N.N. Blokhin Russian Cancer Research Center. The tumor was transplanted into rats intraperitonially. It was shown that the transplanted murine carcinomas did not arouse tumors in rats, but caused pathologic effects: abrupt growth impairment and partial loss in the August rats while in the Wistar rats the growth impairment was slight and there was no loss. Thus, the first, there was no tumor growth in rats and the second, the indicated effects of the murine tumor transplantation were more dramatic in the August rats than thouse in the Wistar rats.

[Effect of the alloxane diabetes on the cardio-vascular system function and lipid peroxidation in rats of different genetic strains].

We have previously shown that the innate increased activity of the NO- system, typical for the August rats, increases vulnerability to alloxane diabetes (ALD). The purpose of this study was to investigate the effect of ALD on the cardiovascular system and lipid peroxidation in rats with different activity of NO-system. The August rats and Wistar rats treated with alloxan (125 mg/kg, s/c, once) were studied 3.5 months after. In August-ALD the double production significantly decreased to a greater extent (by 35%) than in Wistar-ALD (by 17%) compared with the control. As in August-ALD and in Wistar-ALD was observed the similar fall of the relaxation (-dp/dt) of the left ventricle (by 45-49%), but not the contraction rate (+dp/dt). LPO activation in the heart and liver, as well as NO-system (level of nitrates and nitrites in the blood plasma) in August rats were more pronounced than in Wistar rats. The hsp32 level in August rats fell significantly more (by 93% ) than in Wistar rats (by 61%). Pathological changes in the microvasculature of the mesostenium were identical in compared rats. Thus, more pronounced cardiac dysfunction in August-ALD, compared with Wistar-ALD, associated with greater activation of lipid peroxidation and NO-system.

Role of heat shock proteins HSP70 and HSP32 in the protective effect of adaptation of cultured HT22 hippocampal cells to oxidative stress.

Preadaptation of cultured HT22 mouse hippocampal neurons to oxidative stress prevented cell damage induced by severe oxidative stress. This protection manifested in a decrease in metabolic disturbances in neurons. Adaptation of neurons to oxidative stress was accompanied by accumulation of HSP32 and HSP70. HSP synthesis inhibitor quercetin abolished the protective effect of adaptation under conditions of oxidative stress. Activation of HSP70 synthesis in neurons is an important mechanism for adaptive protection of cells.

Inversion of stress response reprogramming phenomenon in lipopolysaccharide-stimulated alveolar macrophages.

The stress response and NO production in reprogrammed proinflammatory or antiinflammatory alveolar macrophages were studied after lipopolysaccharide treatment. Experiments with macrophages not containing HSP70 showed that lipopolysaccharide in a dose of 500 ng/ml induced stress response in cells with the proinflammatory phenotype (as distinct from an antiinflammatory phenotype). The stress response was not observed in HSP70-containing lipopolysaccharide-stimulated proinflammatory macrophages, but occurred in cells with antiinflammatory phenotype. Hence, the presence of HSP70 in alveolar macrophages results in the inversion of the phenomenon of reprogramming of the stress response. Independently on the phenotype, stimulation with lipopolysaccharide was accompanied by a 60-70% increase in NO production by macrophages not containing HSP70. However, NO production by HSP70-containing macrophages did not increase in response to lipopolysaccharide treatment. Our results indicate that reprogramming of the cell response in macrophages does not concern the system for NO synthesis. HSP70 prevents the lipopolysaccharide-induced activation of NO synthesis in alveolar macrophages.

Role of extracellular and intracellular nitric oxide in the regulation of macrophage responses.

We studied the role of nitric oxide in the stress response and apoptosis. Intracellular nitric oxide potentiated the stress response. However, intracellular nitric oxide suppressed the stress response in macrophages of proinflammatory and antiinflammatory phenotypes. Intracellular nitric oxide promoted apoptosis in macrophages of the proinflammatory phenotype, but inhibited this process in cells of the antiinflammatory phenotype. Exogenous nitric oxide synthesized by macrophages protected them from lipopolysaccharide-induced apoptosis. Our results indicate that nitric oxide produces various effects on the stress response and apoptosis in macrophages, which depends on modus operandi.

Stress response and apoptosis in pro- and antiinflammatory macrophages.

We showed that stress response and apoptosis in macrophages depend on the phenotype of their secretory activity and specific biological and physical characteristics of the factor inducing stress-response or apoptosis.