Reconstruction of the Rat Sciatic Nerve by Using Biodegradable and Non-Biodegradable Conduits.

The aim of the study was to compare two types of conduits made of either non-resorbable Reperen or resorbable Tissucol for their effects on the regeneration of the rat sciatic nerve under conditions of stump diastasis. MATERIALS AND METHODS: The experiments were carried out using outbred white male rats of the reproductive age (n=14). The animals were divided into three groups: group 1, intact (n=5), used for studying the morphology of the sciatic nerve; group 2 (n=4) - nerve plastic surgery was performed using a conduit made of non-resorbable Reperen; group 3 (n=5) - surgery was performed using a conduit made of resorbable Tissucol. The animals were anesthetized with isoflurane. After a complete transection of the sciatic nerve in the middle third of the thigh, its stumps were inserted into a conduit of an internal diameter of 2 mm and a length of 10 mm, filled with saline. Diastasis of 5 mm in length was created by spreading the nerve ends and securing the epineurium to the tube edges with 8/0 polypropylene sutures. A total count of myelinated nerve fibers was performed in the area of repair (tubulation) and the distal part of the nerve; the formation of connective tissue sheaths was assessed 14 weeks after the operation. RESULTS: According to the morphological assessment, both types of conduits (resorbable and non-resorbable) caused the similar number of fibers to restore in the distal part of the repaired nerve; clinical characteristics of the animals in both groups were close to each other and to the norm. CONCLUSION: The results allow us to consider the conduit made of non-resorbable Reperen as a device promising for neuroplasty along with the resorbable conduit made of Tissucol.

Ultrastructural Morphological Characterization of Right Atrial and Left Ventricular Rat Cardiomyocytes during Postreperfusion Period.

Immunocytochemistry and transmission electron microscopy were employed to examine the ultrastructural morphometric parameters of the left ventricular cardiomyocytes and right atrial secretory myocytes in rats during early and delayed postreperfusion periods. The revealed alterations in these cells are stereotypical, but differed by their severity, probably due to specific morphofunctional peculiarities of these heart structures.

[QUANTITATIVE ANALYSIS OF BRAIN NATRIURETIC PEPTIDE OF CARDIAC MUSCLE CELLS IN EARLY POSTREPERFUSION PERIOD IN RATS].

The intensity of accumulation and release of brain natriuretic peptide (BNP) in right atrial cardiac muscle cells was investigated in rats after 5 and 60 min from the reperfusion start. Total ischemia was simulated by cardiovascular bundle compression according to V. G. Korpachev. Immunocytochemical identification of BNP in atrial myocyte granules was investigated in ultrathin cuts. We applied polyclonal antibodies to BNP. The calculation of granules (A- and B-types) with BNP was carried out in (38 x 38 µm) visual fields in transmission electronic microscope. The results were assessed using Mann-Whitney U-test (p < 0.05). After 5 min from the reperfusion start, the amount of the granules with BNP did not change compared to intact animals rate. On the 60th min of the post-reperfusion period was shown active accumulation and release of BNP; the amount of A-type granules increased by 134%, B-type granules increased by 210 % in comparison with intacy level. The results showed stimulating effect of ischemic and reperfusion factors on the processes of the brain natriuretic peptide synthesis and secretion in the early post-reperfusion period.