STRUCTURAL CHANGES IN THE ARTERIES OF THE HIND LIMBS OF RATS BY ACUTE ISCHEMIA–REPERFUSION

Abstract

Summary. Arterial tourniquets are widely used both in clinical practice (for example for angio- and arthroplasty) and in military medicine by the injury of the limbs. After removing the tourniquet and blood supply restoration to the limb arises a multifactorial lesion of tissues both ischemic and distant from the site of ischemia. However, morphological changes in the wall of the main arteries by the acute ischemia-reperfusion are insufficiently covered in the medical literature.

The aim of the study – to establish the peculiarities of structural changes of the main arteries of the rat’s hind limbs by acute ischemia, caused by application of the arterial tourniquet.

Materials and Methods. The microscopic study of histological preparations with transverse sections of the femoral, popliteal and tibial arteries of the hind limbs of 30 rats under condition of experimental acute ischemia was performed. Acute ischemia was caused by application of SWAT rubber bands on the hind limbs of animals, 5–6 mm in width, at the inguinal fold level within 2 hours under thiopental  anesthesia. A reperfusion was modeled by removing the tourniquet. During the experiment, all the animals were divided into 5 study groups of 6 rats in each group. The  model of the early postischemic period was represented by groups of animals with reperfusion changes on the 1st, 2nd hour and 1st day after removal of the tourniquet, and model of the late reperfusion period was represented by groups of animals with reperfusion changes on the 7th and 14th day after tourniquet removal. The histological examination was carried out according to standard methods. Sections of the arteries were stained with hematoxylin and eosin, with  resorcinol-fuchsin according to Weigart, according to method of Van Gizon and azan according to the method of Heidenhain, and were examined with a light microscope.

Results. Morphometric studies had established that morphological criteria of remodeling of the arteries of the femoral, popliteal and tibial areas during the early reperfusion period were histological changes of all structural elements of their wall, which were manifested by edema and thickening of all its layers, significant edema and exfoliation of endothelial cells with the development of parietal microthrombosis, uneven corrugation and ruptures of basal membrane, violation of integrity of elastic fibers, fragmentation of leiomyocytes with vacuolation of their sarcoplasm, leukocyte infiltration of the muscular layer and perivasal space, as well as perivascular diapedeous haemorrhages. During the late reperfusion period, the severity of the above-mentioned changes was significantly decreased, while simultaneously the development of granulation tissue in the perivascular space of the main arteries of the hind limbs of rats was happening.

Conclusions. The results of morphological study confirm the remodeling of the wall of main arteries of hind limbs of the rats as a result of the development of ischemia-reperfusion syndrome in experimental animals, which was manifested by a complex of pathomorphological changes of all arterial membranes. These changes reached a maximum on 1st day after removal of the tourniquet, and gradually decreased in the late reperfusion period after 7 and 14 days.