ИСТИНА

Diabetes mellitus (DM) is a systemic disease that is gaining higher and higher social problem due to the quickly growing number of Earth population suffering from it and due to severe alterations of vitally important systems of the human organism involved including the cardiovascular system. The major long-term DM complications are related to the damage to blood vessels and capillaries (causes microangiopathy) and impairment of blood rheological properties. This leads to doubling the risk of cardiovascular diseases. It is obvious that control and monitoring of DM complications is very important, in particular microrheological and rheological parameters. The rheological parameters are mostly related to the deformability and aggregation properties of red blood cells (RBCs), which are expected to be impaired in DM patients. The main goal of this work was to estimate the alterations of these parameters for rat and human blood in case of non-insulin-dependent DM (NIDDM) and insulin-dependent DM (IDDM). In this work, we conducted measurements based on laser aggregometry and diffractometry techniques. Laser diffractometry is a convenient, fast and relatively simple technique for measuring the RBCs deformability. The essence of this technique is in obtaining and subsequent analysis of the diffraction patterns from a highly diluted suspension of RBCs at rest and shear flow [1]. Dependence of the diffraction pattern elongation on shear stress characterizes the ability of RBCs to deform. Laser aggregometry technique allows to study the kinetics of the spontaneous aggregation (time dependence of light intensity backscattered from a sample of whole blood in the rest) and shear-induced disaggregation (shear stress dependence of light intensity backscattered from a sample of whole blood under shear flow) of RBCs for obtaining characteristic times of linear (T1) and three-dimensional (T2) aggregates formation, as well as hydrodynamic strength of RBCs [2]. All experimental measurements were performed with human blood drawn from patients with IDDM (N=8), NIDDM (N=10) and practically healthy volunteers (N=10), as well as with rat blood drawn from healthy animals (N=8) and from rats with experimentally induced DM (N=8). The experimentally obtained results show that the microrheological properties are impaired in case of DM diseases. For instance, the ability of human RBCs to deform in shear flow decreases by about 8-10 % (in cases of both IDDM and NIDDM) in comparison with that in the control group. It has been shown that the reduction of RBCs deformability in case of DM is mainly related with the increasing of RBCs membranes rigidity. The parameter T2 decreases by about 20-25 % (in cases of both IDDM and NIDDM) in comparison with that in the control group while the parameter T1 increases by about 20% in case of NIDDM and about 60 % in case of IDDM. Microrheological alterations in the blood of DM rats are quantitatively different from those in human DM patients. This may be due to the fact that DM rats do no suffer from accompany diseases and complications characteristic of human DM patients.