| Abstract: | In the experiments performed in 108 dogs, structure of the vascular bed, elongated by means of Ilizarov's apparatus in the extremity pelvic segment, has been studied, as well as the hemostatic system under various regimens of distraction. Under a spare regimen reorientation of the microcirculatory bed links and its neural apparatus according to the lines of tension and distension forces are revealed, as well as new formation and growth of capillaries, nerve fibers and terminals. In the vessels of the muscular type, at the level of the osseous regenerate, the following changes are described: distractive rearrangement and intercalated growth (such as activation of biosynthetic processes in endothelium, adventitium and smooth muscle (SMC) cells), intensive proliferation and longitudinal reorientation of the activated SMC in the middle tunic, in the larger arteries a powerful longitudinal muscular layer is formed between the endothelium and the internal elastic membrane. The tendency for hypercoagulation, that exists at that time, is compensated by antithrombogenic and fibrinolitic blood activity. Under an elevated rate of the distraction or under an unstable fixation of the bone fragments in the apparatus, hypercoagulation is not compensated till the end of the experiment, and in the vessels, simultaneously with the distractive rearrangement, thrombosis, recalibration and obliteration are observed. The data observed and those of the literature, demonstrate that vascular adaptation to a dosed distraction is performed by means of certain rearrangements in the walls and of intercalated growth influenced by the effect of the distension forces. These phenomenon make the base of the mechanisms developing in the organism during its evolution and ontogenesis. |
