Structural and morphometric reorganization of the lung vessels after experimental thermal trauma and application of lyophilized xenograft substrate
The aim of this work was to establish the histologic and morphometric vascular reorganization of the lungs in animals after thermal damage in the application of crushed of lyophilized xenograft substrate.
Materials and methods. The experiment was carried out on 30 mature white male rats. Third degree burn was applied under ether anesthesia with copper plates heated in boiling water to a temperature 97-1000C. Size of the area lesions amounted 18-20% of the shaved body surface of rats. Early necrectomy of damaged skin was performed 1 day after causing burns. Closure of wound which formed, committed by crushed lyophilized xenographt substrate. Experimental animals were decapitated at 7, 14 and 21 days.
Results. The conducted histologic and morphometric study on day 7 showed that already in this period less pronounced destructive changes vascular permeability and expression of vascular walls, especially microvasculature. Morphometric found a significant increase in external diameter and narrowing of internal in the arteries of medium caliber, so Vohenvort index less than 1.33 times the rate of animals which correction of thermal injury did not commit. Similarly, changing morphometric data in small caliber arteries.
Submicroscopic in this term of experiment installed less distinct changes in hemocapillary walls of the alveoli of the lungs, they are not so far advanced and filled with blood. For basement membrane typical swelling in a greater extent, available land on which it has no clear contours. In endothelial cells are round-oval nuclei, with shallow intussusception of karyotheca. Edotelialnyh cell cytoplasm moderately swollen. In the peripheral areas of endothelial cytoplasm we can see growing number of pinocytosys vesicles and caveolae.
Histologically on 14 days of the experiment observed that the blood vessels of the lungs moderately blood-filled. Morphometric set reduction in external diameter arteries of medium caliber to 1.08 times and increase in internal in 1.07 times in comparison with the indexes in group of animals without correction burn. Therefore Vohenvort index of these arteries fewer in 1.43 times, relative index of animals without correction. Similar morphometric parameters found in arteries of small caliber.
Microscopically for the conditions of using lyophilized xenograft substrate on 21 day of experiment structural organization of the lungs vascular significantly improved compared to previous terms. Morphometric these changes are confirmed by significant decrease in the index of medium-caliber arteries Vohenvort at 1.74 times and small - to 1.73 times in comparison with values in the group of animals without correction care and their approach to performance intact.
At the ultrastructural level on 14 and 21 days in most hemocapillary walls of the alveoli of the lungs we can see less extent of damage of its components. In moderate their gaps blood corpuscles, mainly red blood cells. Ellipse shape core have clear contours and minor intussusception membranes of karyotheca. The cytoplasms of endothelial cells have moderate electron density. Thin peripheral areas of endothelial cells contain numerous pinocytosys vesicles and caveolae. At this time of experiment basement membrane integrity is preserved as part of the aero-hematic barrier.
Conclusions. Thus, the results of histologic and morphometric studies of the lungs indicate that closure of burn wounds by crushed lyophilized xenograft substrate after conducting early necrosectomy of affected skin prevents the action of pathogenic factors on the vascular system body, reduces the degree of their damage. Therefore, at the end of the experiment takes place relative normalization of structural organization and their morphometric parameters.