Byzov D. Application of low temperatures to create devitalized vascular scaffolds

The research object is influence of low temperatures and ionizing irradiation that used for devitalization of small diameter arteries in vitro on their morpho-functional properties including after xenotransplantation. The research aim is experimental estimating of efficiency of low temperatures in combination with ionizing irradiation for devitalization of small diameter arteries, developing of method of vascular xenoscaffolds obtaining. The research methods: biomicroscopical, histological, electron-microscopical, biophysical and statistical. Equipment: linear accelerator of electrons LUE-10 (Russia), electron microscope PEM-125K (Russia), optical microscope Meiji Techno (Japan), multipurpose deforming device FP 100/1 (VEB TIW Rauenstein, Germany); electron pressure transducer MPX-5700DP (Freescale Semiconductor, China). Adequacy of devitalized vascular xenoscaffolds functioning after experimental prosthesis was estimated by clinical signs. The thesis is devoted to investigation of the effect of low temperatures in combination with ionizing irradiation on xenogenous arteries of small diameter ( 6mm), used with the aim of their devitalization for further application as vascular bioprostheses. There have been developed the methods of devitalizing the arteries with the determined physical factors. The advantage of their combined effect was shown. It has been established that freeze-thawing and following irradiation in the doses of 25-50 kGy lead to a complete de-endothelization of arteries and destruction of smooth muscle cells of vascular media when preserving the structural integrity of connective tissue carcass and biomechanical strength of arterial wall. Devitalized arteries did not cause the rejections during xenoimplantation and were not subjected to gradual remodeling. There has been shown their integral functioning as the prostheses of rabbit's abdominal aorta during 12 months. Acute thromboses resulted from the properties of xenografts and rejections were absent at all the observation terms.