Cellular effects of splenectomy on liver regeneration after 70% resection

Andrey Elchaninov^1*Polina Vishnyakova²Elena Gantsova³Miroslava Chirkova⁴Viktoriya Karyagina²Anatoliy Larkin⁵Evgeniya Kananykhina³Maria Kuznetsova²Ibrahim Atabekov⁴Evgeny Karpulevich⁴Silachev Denis²Dmitry Trofimov²Dmitry Goldshtein⁶Timur Fatkhudinov³Gennady Sukhikh²

• ¹Avtsyn Research Institute of Human Morphology of FSBI "Petrovsky National Research Centre of Surgery", Moscow, Russia
• ²National Medical Research Center Of Obstetrics, Gynecology And Perinatology Named After Academician V.I. Kulakova, Moscow, Moscow Oblast, Russia
• ³Avtsyn Research Institute of Human Morphology of FSBI 'Petrovsky National Research Centre of Surgery', Moscow, Moscow Oblast, Russia
• ⁴Institute for System Programming (RAS), Moscow, Moscow Oblast, Russia
• ⁵National Research University Higher School of Economics, Moscow, Moscow Oblast, Russia
• ⁶Research Centre for Medical Genetics, Moscow, Moscow Oblast, Russia

Mammalian liver regeneration is a complex process, the regulation of which involves many mechanisms. The immune system has a pronounced influence on the course of reparative processes in mammals. The hepatic portal vein system provides a direct anatomical connection between the liver and the spleen -the largest lymphoid organ in mammals. Accordingly, the spleen may have a direct effect on liver regeneration as a source of biologically active substances and migrating leukocytes. Specific mechanisms of such influence remain understudied. This study aimed to assess the effect of splenectomy on liver regeneration after 70% resection in mouse model. Murine model of liver regeneration after 70% resection was reproduced in C57BL/6 male mice, some of them splenectomized 7 days before the liver resection. Proliferation marker Ki67 in the liver was assessed by immunohistochemistry and the protein content for cyclin D 1 , cyclin A 2 and p53 in the liver was assessed by Western blotting. Using TUNEL assay, an increase in the number of apoptotic cells was detected. The highest number of TUNEL+ cells was detected 1 day after liver resection, while the number of apoptotic cells in animals with prior splenectomy was significantly lower compared to animals with preserved spleen. The dynamics of Ly6C+ monocytes and Ly6G+ leukocytes were studied by flow cytometry. Macrophages were isolated from the regenerating liver using magnetic sorting for F4/80 and their gene expression profiles were analyzed using Clariom™ S Assay, mouse.