Anti-inflammatory Activity of Mesenchymal Stem Cells in λ-Carrageenan-Induced Chronic Inflammation in Rats: Reactions of the Blood System, Leukocyte-Monocyte Ratio

The variety of chronic diseases caused by a chronic inflammatory process is an unresolved problem in developed countries. Due to this, modern medicine lacks effective, pathogenetic mechanisms of treatment or at least improvement of the quality of life of people with so-called diseases of civilization. The purpose of this study was to investigate the anti-inflammatory and immunomodulatory ability of mesenchymal stem cells (MSCs) in a model of λ-carrageenan secondary chronic inflammation in rats. MSCs derived from rat femoral epiphysis were used. At the current level of medicine, many highly specific markers of chronic inflammation are available that will also be studied later (α-TNF, IL 6, C-reactive protein); however, this article will consider the study of the most accessible but at the same time very informative indicators of the inflammatory process-a common total blood count-leukocytes, leukocyte formula, and LMR. The study was performed on 132 male Wistar rats weighing 180-200 g, which were divided into 12 groups. The inflammation was caused by the introduction of 10 mg λ-carrageenan intramuscular in right hip. After induction of edema, the experimental groups of rats were administered MSCs into the inflamed site, in the amount of 1-2 million cells once. Blood sampling was performed from 6 h to 28 days. With one-way ANOVA followed by Tukey-Kramer multiple comparisons test, p < 0.05, we compared our groups of animals. In the detailed dynamics of inflammation, from the 6th hour to the 28th day (ten terms), the reactions of the blood system and their mechanisms were investigated. There were intact rats-6 animals without any interventions, as well as rats administered MSCs without causing inflammation (6 animals) in experiment. In this experiment, the lymphocyte-monocyte ratio in rats is described for the first time, demonstrating the suppression of chronic inflammation by means of MSCs.

Keywords: carrageenan; chronic inflammation; lymphocyte-monocyte ratio; stem cells.