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Impaired function of postoperative macrophages from zinc-deficient rats decreases collagen contraction. Brief report
M R Ghassemifar1, M G Olsson, M S Agren
1Faculty of Health Science, Department of Pathology II, Linköping, Sweden.
Abstract:
Zinc deficiency impairs connective tissue contraction in the perforated rat mesentery model. Since the rat mesentery is almost avascular, free peritoneal macrophages are important for mesenteric repair. Impairment of contraction may thus be caused either by a direct effect of zinc deficiency on tissue cells or by hampered macrophage function. To further elucidate the role of macrophages in tissue contraction, we studied their effect on lattice contraction. A number of typical functions of macrophages in zinc deficiency were also investigated. Lattice contraction was significantly impaired by conditioned medium from zinc-deficient macrophages. Zinc deficiency did not influence peripheral blood leukocyte number, but postoperatively the number of peritoneal macrophages increased on days 7 and 10. A significant release of lysosomal enzymes from macrophages was recorded during phagocytosis, whilst no difference was observed between controls and zinc-deficient macrophages. Superoxide anion generation during phagocytosis was not significantly increased in zinc deficiency. Conditioned medium from zinc-deficient macrophages was shown to impair lattice contraction in vitro and the results are compatible with impaired macrophage function as a cause of decreased connective tissue contraction in vivo.
Insights
Zinc deficiency impairs connective tissue repair by affecting macrophage function. This study shows zinc-deficient macrophages hinder tissue lattice contraction, suggesting a key role for these immune cells in wound healing.
Area of Science:
- Immunology
- Nutritional Science
- Tissue Repair
Background:
- Zinc is crucial for connective tissue repair, but the precise mechanisms, especially the role of macrophages, are not fully understood.
- The rat mesentery model, being largely avascular, relies on peritoneal macrophages for repair processes.
- Zinc deficiency's impact on macrophage function and subsequent tissue contraction requires further investigation.
Purpose of the Study:
- To investigate the role of macrophages in impaired connective tissue contraction observed in zinc deficiency.
- To determine if zinc deficiency directly affects tissue cells or compromises macrophage function.
- To analyze specific macrophage functions, including their effect on lattice contraction.
Main Methods:
- Utilized a rat mesentery perforation model to study connective tissue repair.
- Assessed lattice contraction in vitro using conditioned medium from zinc-deficient and control macrophages.
- Quantified peritoneal macrophage numbers and investigated lysosomal enzyme release and superoxide anion generation during phagocytosis.
Main Results:
- Conditioned medium from zinc-deficient macrophages significantly impaired in vitro lattice contraction.
- Postoperative peritoneal macrophage numbers increased in zinc-deficient rats, but their function was compromised.
- No significant differences were found in lysosomal enzyme release or superoxide anion generation during phagocytosis between zinc-deficient and control macrophages.
Conclusions:
- Impaired macrophage function, rather than direct cellular effects, is likely responsible for decreased connective tissue contraction in zinc deficiency.
- Macrophages play a critical role in mediating connective tissue repair, and their function is significantly hampered by zinc deficiency.
- These findings highlight the importance of adequate zinc levels for optimal immune cell function in wound healing.