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Neutrophils express tumor necrosis factor-alpha during mouse skin wound healing
Abstract:
The expression pattern of tumor necrosis factor-alpha (TNF-alpha) mRNA and protein was examined in vivo in experimental mouse skin wounds by in situ hybridization and immunohistochemistry. TNF-alpha mRNA and protein is detected in a distinct layer of mainly neutrophils subadjacent to the would clot. The layer of TNF-alpha-positive cells extends from the margin of the advancing epithelial outgrowth to the opposing one. By in situ hybridization the TNF-alpha mRNA is detectable 12 h after wounding; the signal peaks after 72 h and remains visible up to at least 120 h after wounding. TNF-alpha mRNA could not be detected in the normal skin or in 5-hour-old wounds. Immunohistochemical staining for TNF-alpha and macrophages on adjacent sections confirms that the main part of TNF-alpha-positive cells are polymorphonuclear neutrophils and shows that most of the cells located just beneath the layer of TNF-alpha-positive neutrophils are macrophages with weak TNF-alpha immunoreactivity. The data reported here show that neutrophils serve as an important source of TNF-alpha during healing of mouse skin wounds. We suggest that this specific expression of TNF-alpha is related to the process of re-epithelialization.
Insights
Neutrophils are a key source of tumor necrosis factor-alpha (TNF-alpha) during mouse skin wound healing. This specific expression of TNF-alpha in neutrophils is linked to the re-epithelialization process.
Area of Science:
- Wound Healing Research
- Immunology
- Molecular Biology
Background:
- Tumor necrosis factor-alpha (TNF-alpha) plays a role in inflammatory processes.
- Understanding the cellular sources of TNF-alpha during tissue repair is crucial.
Purpose of the Study:
- To investigate the expression pattern of TNF-alpha mRNA and protein in mouse skin wounds.
- To identify the specific cell types responsible for TNF-alpha production during wound healing.
Main Methods:
- In vivo study using experimental mouse skin wounds.
- In situ hybridization to detect TNF-alpha mRNA.
- Immunohistochemistry to detect TNF-alpha protein and cell types (neutrophils, macrophages).
Main Results:
- TNF-alpha mRNA and protein were detected in neutrophils adjacent to the wound clot.
- TNF-alpha expression began 12 hours post-wounding, peaked at 72 hours, and persisted up to 120 hours.
- Macrophages located beneath TNF-alpha-positive neutrophils showed weak immunoreactivity.
Conclusions:
- Neutrophils are a significant source of TNF-alpha during mouse skin wound healing.
- The localized expression of TNF-alpha by neutrophils may be related to the re-epithelialization phase of wound repair.