The role of arterio-venous anastomoses in the neutrophilic granulocytes circulation

Abstract

Migration of neutrophilic granulocytes (NG), whose main function is phagocytosis, is primarily caused by the venule lumen. Nevertheless, NGs are often “blamed” for their ability to block microcirculation in the systemic circulation and thus to develop the no-reflow phenomenon in the cerebrum and myocardium. Apparently, NGs are a priori believed to enter the venous bed trans capillary, although their morphological features should prevent it. Are NGs able to circulate into venules via arterio-venous anastomoses (AVA)? The aim of the research is to elucidate the role of AVA in neutrophilic granulocyte circulation. The paper presents the study of the intestine, skeletal muscles, myocardium, cerebrum, peritoneum, and spleen in cats (n=7) and white rates (n=17). The research methods are intravascular impregnation by the Ranvier method, a universal method of impregnation with various silver salts, routine histological methods of staining paraffin sections. In intact animals, neutrophilic granulocytes enter the venules via AVAs only. In the myocardium and cerebrum, which have no AVAs, due to the blood separation phenomenon, NGs enter the epicardium exclusively in the former case and the facial soft tissues and pachymeninx in the latter.