Abstract
The purpose of this study – is to find methods for additional processing of connective tissue structures of allografts before lyophilization, reducing the damaging effect of drying itself, as well as allowing simultaneous sterilization of the graft.
Material and methods. The material was samples of allografts that passed standard “decellularization” with digitonin
and EDTA. After “decellularization” and "sterilization" in a solution of antibiotics for a day according to the standard scheme, part of the tissue of allografts was used as a control, and the other part was subjected to gradient processing in a solution of sucrose at a concentration of 20% (4 hours), then 40% (4 hours) and then 80% (1 more day) with uniform mixing at a speed of 60 rpm and heating to 35 °C. After this treatment, allografts were placed in a freezer and frozen to –40 °C at a speed of 1 °C/min, then placed in a chilled “Labconco” freeze drying chamber, where a discharge of about 15 mbar was created. The drying procedure took about 8 hours, after which part of the allograft was used for bacteriological sterility control, and the other part – for histological analysis.
Results. Under bacteriological control, the growth of microorganisms was not detected during incubation in aerobic and anaerobic conditions. Histological research has shown that pretreatment with sucrose followed by lyophilization leads to dehydration of the collagen matrix of the aortic wall. When compared with the results of cryopreservation, there is a less damage effect of the new method of lyophilization on the structure of the aortic wall. The aortic valve leaf remained intact. When compared with control samples that were not subjected to lyophilization or cryopreservation, we note a higher quality of the matrix during lyophilization after gradient treatment with sucrose than during
traditional cryopreservation.
Conclusion. Pre-dehydration in concentrated sucrose solutions of the tissue matrix before lyophilization contributes to better preservation of the tissue structure than without the use of this method.
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About the authors
- Dmitriy V. Britikov, Dr. Med. Sc., Head of the group, ORCID
- Nataliya P. Bakuleva, Cand. Chem. Sc., Head of Laboratory ORCID
- David R. Tevosov, Junior Researcher, Pathologist, ORCID
- Leo A. Boсkeria, Academician of RAS and RAMS, President of Center, ORCID
