[Long-fragment DNA of blood plasma as one of the criteria of individual sensitivity to emotional stress and to cerebral ischemia]

Abstract

Intravenous injection ofpolyethylenoxide WSR-301 reducing hydrodynamic blood resistance (Toms effect) improves gas exchange in the lungs and halved lethality of the animals with cerebral ischemia. The aim of the study was to establish whether free plasma DNA influences blood gases and lethality of the animals with brain ischemia. Common carotid arteries were ligated for 15 min in intact stressed and tested in the open field Wistar male rats, then some of the rats received intravenous solution of homologous long-fragment DNA (20x10(-6) g/ml of blood). Cerebral circulation, acid-base equilibrium, paO2, paCO2, asymptotic blood viscosity, plasmic concentration and length of DNA fragments in plasma, lethality and neurological status of the survivors were studied. It was found that long fragments of rat DNA show hydrodynamic Toms effect. In normal passive rats sensitive to cerebral ischemia part of plasm DNA is fragmented, gas composition and blood viscosity of blood is worse (p < 0.05) than in active animals. There is a direct correlation between the level of long-fragment DNA in plasm and paO2 (r = 0.55) and inverse--with paCO2 (r = -0.84). Intravenous injection of long-fragment DNA improved the course and reduced lethality of brain ischemia 2-3-fold. Thus, qualitative and quantitative characteristics of plasma circulating DNA are responsible for differences in blood gases in rats differently tolerable to cerebral ischemia and can serve as one of the criteria of individual sensitivity to it being essential in pathogenesis of ischemic stroke.