Poster (download) Irina Yurievna Ishchenko1, Svetlana Viktorovna Michurina2, Sergey Alekseevich Arkhipov3, Andrey Yurievich Letyagin4, Maxim Aleksandrovich Korolev5, Evgenii Leonidovich Zavjalov61Group of experimental pharmacology SRICEL – a branch of ICG SB RAS Novosibirsk, Russia, irenisch@mail.ru2Group of experimental pharmacology SRICEL – a branch of ICG SB RAS Novosibirsk, Russia, s.michurina@ngs.ru3Group of experimental pharmacology SRICEL – a branch of ICG SB RAS Novosibirsk, Russia, arhipowsergei@yandex.ru4Laboratory of pharmaceutical technologies SRICEL – a branch of ICG SB RAS Novosibirsk, Russia, letyagin-andrey@yandex.ru5Laboratory of connective tissue pathology SRICEL – a branch of ICG SB RAS Novosibirsk, Russia, kormax@bk.ru6Center of genetis resources of laboratory animals ICG SB RAS Novosibirsk, Russia, zavjalov@bionet.nsc.ru The expression of the lymphatic vessel endothelial receptor-1 hyaluronan-1 (LYVE-1) was studied in the liver cells of male C57BL / 6 mice, which were kept for 14 days under 24-hour illumination (mice with functional pinealectomy). Used immunohistochemical analysis (indirect avidin-biotin-ABC-peroxidase method) and morphometric evaluation. A 2-fold decrease in the LIVE-1 expression area was detected against a 2% increase in the optical density of LIVE-1 staining in mouse liver cells after chronic continuous illumination. Weak expression of LYVE-1 on the membranes of endothelial cells of the sinusoids of the liver may indicate a violation of the functioning of the fields of fenestration of these cells. This can lead to a decrease in the endocytotic activity of the latter, difficulty in the exchange of hematotissue tissues, deterioration of lymphatic drainage and the development of tissue hypoxia in the liver of mice with functional pinealectomy.