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Background: Postoperative peritoneal adhesions arise from a dysregulated wound-healing response in which macrophages may have context-dependent effects. We investigated the contribution of macrophage-rich peritoneal and mesenteric compartments, the origin of macrophage-like cells in ischemic lesions, and the association between CCR2-dependent recruitment and postoperative inflammatory and reparative gene expression. Methods: Using a murine ischemic-button model, we assessed the effects of clodronate liposome treatment, bone marrow chimerism, and global CCR2 deficiency. Adhesion formation, F4/80+ cell accumulation, donor-marker expression, and selected inflammatory and wound-healing-associated transcripts were analyzed at predefined postoperative time points. Results: Clodronate liposome treatment was associated with reduced adhesion formation and substantial depletion of F4/80+ cells in peritoneal lavage and mesenteric tissue. However, F4/80+ cell numbers within ischemic buttons at postoperative day 3 were not significantly reduced, indicating that the depletion experiment does not establish selective depletion of all lesional macrophages. Bone marrow chimera experiments identified donor-marker-positive, F4/80+ cells within ischemic buttons, supporting recruitment of hematopoietic cells with a macrophage-like phenotype. CCR2 deficiency reduced F4/80+ cell accumulation in ischemic buttons and was associated with increased adhesion scores and altered expression of inflammatory and wound-healing-associated genes. These findings identify differential associations of clodronate-sensitive macrophage-rich compartments and CCR2-dependent hematopoietic recruitment with postoperative adhesion formation. Conclusions: Depletion of macrophage-rich peritoneal and mesenteric compartments was associated with reduced adhesion formation, whereas global CCR2 deficiency was associated with fewer lesional F4/80+ cells and greater adhesion severity. Because clodronate depletion, F4/80 staining, bone marrow chimerism, and global CCR2 deficiency do not provide cell-specific or fate-mapped resolution, these data do not establish distinct resident versus infiltrating macrophage functions or a reparative phenotype of CCR2-dependent cells. Cell-specific and temporally resolved validation is required to define the contributions and temporal relationships of individual macrophage subsets. Full article

Objective: Post-surgical peritoneal adhesions are a serious problem for the quality of life and fertility. Yet there are no effective ways of preventing their occurrence. The gap junction protein Cx43 is known to be involved in fibrosis in several different organs and disease conditions often associated with inflammation. Here we examined the Cx43 dynamic expression in an ischemic button model of surgical adhesions. Methods: Using the mouse ischemic button model, Cx43 antisense was delivered in Pluronic gel to attenuate Cx43 expression. The severity of button formation and immunofluorescence analysis of Cx43 and TGF-β1 were performed. The concentration of tissue plasminogen activator via ELISA was also performed. Results: As early as 6 h after button formation, the Cx43 levels were elevated in and around the button and some weak adhesions were formed. By 24 h Cx43 levels had increased further and adhesions were more defined. At 7 days the adhesions were much more robust, opaque, and vascularized, requiring blunt or sharp dissection to break them. Cx43 antisense attenuated its upregulation and, reduced the number and severity of adhesions that formed. Conclusion: Targeting Cx43 after surgical procedures may be a potential therapeutic strategy for preventing adhesion formation or at least reducing their severity. Full article