| Abstrakt: |
Introduction and Aim: Wound healing is divided into consecutive phases which are blood clotting, inflammation, tissue growth and tissue remodeling. Due to several complications, patients ought to undergo repeated surgical interventions. Since the elements of immune system, basically myeloid cells, play decisive roles in tissue repair, this study aims to assess the status of myeloid cells in repeated surgery model. Methods: BALB/c mice were undergone laparotomy (LT) with ~3.5 cm sagittal cut through abdominal wall. The mice with single operation (once-LT) were sacrificed on days 2 and 7 days following laparotomy. A group of mice was re-operated (twice-LT) from the same wound trajectory whereas another group was undergone an additional surgery (thrice-LT) and these mice sacrificed 7 days following the last LT. Non-operated mice were control group. Peripheral blood, liver, spleen and abdominal wall specimens were collected for macroscopic and histopathological evaluation. The distribution and number monocytic and granulocytic myeloid cells amongst these compartments were evaluated by CD11b, Gr-1, Ly6G, Ly6C flow cytometry. Epithelialization, fibroblastic activity, ulceration, neutrophil and lymphohistiocyte infiltration were scored in the LT area. Trichrome and myeloperoxidase immunohistochemistry were performed on specimens. The capacity of granulocytic cells to modulate T cell responses were assessed by CFSE assay. Production of reactive oxygen species (ROS) was determined with DCFDA. Results: Tissue healing was apparent on day 2 whereas incomplete epithelialization and inflammation were still evidenced on day 7. As an early event, the number of leukocytes were decreased both in the spleen (especially CD11b+Ly6C+Ly6G- monocytes) and blood. On day 7, spleen became highly populated by CD11b+Ly6C+Ly6G+ granulocytes. The liver was the least affected compartment. Second LT provoked fibrosis and scar formation in the abdominal wound characterized with lymphohistiocytes and lack of neutrophils. Monocyte enrichment was apparent both in the spleen and liver, leukocytosis was sustained in the blood. Enlargement of spleen was observed at this stage whereas the additional hit by thrice-LT resulted in splenomegaly. Wound area became ulcerative and highly infiltrated by neutrophils. Neurtophilia was a result of purging of splenic leukocytes into the circulation. These CD11b+Ly6C+Ly6G+ (even the low-density granulocytes obtained from 1077 Ficoll gradient) more effectively supported T cell proliferation than control neutrophils. They had ROS production capacity. Conclusion: According to our results, local inflammation triggered by repeated surgery results in chronic inflammation and outspreads to a systemic level. This leads to severe neutrophilia reinforced by the spleen that interferes with wound healing. [ABSTRACT FROM AUTHOR] |
