The Effect Of Serious Trauma On Differentiation And Migration Of Monocytes To Dendritic Cells

Trauma is a leading threaten of health of human being and productivity of human society. Trauma often leads to severe disorder of the immune system with an increased susceptibility to septic complications and MODS. A better understanding of these mechanisms would assist the introduction of preventive and therapeutic strategies into clinical practice.Dendritic cells (DC) are professional antigen presenting cells, which display an extraordinary capacity to stimulate na?ve T cells and initiate primary immune responses. The powerful adjuvant activity that DCs possess in stimulating specific CD4 and CD8 T cell responses has made them important in infections, allograft reactions, allergic and autoimmune diseases, and cancer.Studies have shown significant changing in quantity, antigen-presentation and cytokine production of DC after trauma and following complications. Tissue invasion by pathogens induces the recruitment of blood DC to the site of infection and contributes to their subsequent migration to secondary lymphoid organs. The effect of trauma on differentiation and migration of dendritic cells has not been reported yet.Objectives:To observe the effect of serious trauma on differentiation and migration of monocytes to dendritic cells.Methods:1. FITC-labeled polystyrene microspheres were injected subcutaneously,the total cells of draining lymph nodes were counted and analyzed by flow cytometry.2. Local infiltration of inflamed cells and remained fluorescent substance were observed by fluorescent microscope and confocal microscope.3. Remained fluorescent substances were measured by acetone extractions test, and then the clearance rates were calculated.4. FITC microspheres loaded inflammatory monocytes were collected from the peritoneal and transferred , also the total cells of draining lymph nodes were counted and analyzed by flow cytometry.Results:1. The percentage and quantity of FITC+ cells in draining lymph nodes of serious trauma animals(0.021±0.009%, 492±211) was significantly lower than that of control animals(0.040±0.012%, 726±218, P<0.05).2. The percentage and quantity of MHCⅡ+ cells in draining lymph nodes of serious trauma animals(20.79±2.79%, 0.51±0.10×106) was significantly higher than that of control animals(17.39±2.11%,0.31±0.06×106, P<0.05). The quantity of MHCⅡ+ cells in FITC+ cells of serious trauma animals(320±112)was significantly lower than that of control animals(707±197, P<0.05). There is no significantly difference of the percentage of MHCⅡ+ cells in FITC+ cells between serious trauma animals(83.33±28.87%)and control animals(88.90±19.23%).3. During early period after trauma, the inflamed cells infiltration of injection area was seen more obviously. The infiltrating cells express higher CD11b than control animals.4. The fluorescence clearance rates of serious trauma animals were significantly higher than that of control animals(P<0.01 or P<0.05)on day1, 2, 4 and 6 post microspheres injection.5. After the FITC microspheres loaded inflammatory monocytes were transferred, the percentage and quantity of FITC+ cells in draining lymph nodes of serious trauma animals(0.09±0.02 % , 2249±344) was significantly lower than that of control animals(0.22±0.05%,3974±725, P<0.05).Discussion and Conclusions1. The disorder of differentiation and migration of monocytes to dendritic cells in vivo occurred in mice after trauma.2. The disorder is not attributed to the depression of monocytes infiltration to inflamed area nor antigen uptaking and migration starting of phagocytic cells.3. The disorder is attributed to phagocytic cells migration from local to draining lymph nodes.