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Studies on mRNA expression of tissue-type plasminogen activator in bruises for wound age estimation
Masataka Takamiya1, Kiyoshi Saigusa, Reiko Kumagai
1Department of Legal Medicine, Iwate Medical University School of Medicine, 19-1 Uchimaru, 020-8505 Morioka, Japan. mtakamiy@iwate-med.ac.jp
Abstract:
We investigated mRNA expression of tissue-type plasminogen activator (tPA) and inflammatory cell dynamics for wound age estimation of bruises in mice. Neutrophils were detected from 1 h post-injury. Up to 8 h, they accumulated in subcutaneous tissue and the lower part of the dermis, and thereafter they extended to all the layers. Macrophages became detectable 3 h post-injury, and moderate infiltration of lymphocytes was seen from 144 h. In addition, epidermal thickening was also seen from 72 h. tPA mRNA expression peaked at 1 h, and increased slightly at 72 h post-injury. tPA mRNA was detected in epidermal cells, fibroblasts, and endothelial cells before and after injury, from 3 h in neutrophils and from 72 h in macrophages, respectively. This study presents the time-dependent expression of tPA mRNA in bruises in relation to temporal histologic characteristics during wound healing, which was considered to be useful for wound age estimation. Furthermore, it is suggested that tPA plays an important role in the first step of tissue remodeling.
Insights
This study reveals that tissue-type plasminogen activator (tPA) mRNA expression and inflammatory cell dynamics in mouse bruises can estimate wound age. These findings offer insights into bruise healing and tissue remodeling processes.
Area of Science:
- Forensic Pathology
- Histology
- Molecular Biology
Background:
- Bruise age estimation is crucial in forensic investigations.
- Understanding the temporal changes in bruise histology and molecular markers is essential for accurate aging.
Purpose of the Study:
- To investigate the mRNA expression of tissue-type plasminogen activator (tPA) and inflammatory cell dynamics in mouse bruises.
- To correlate these findings with histologic characteristics for wound age estimation.
- To explore the role of tPA in the initial stages of tissue remodeling.
Main Methods:
- Mice were subjected to injury to create bruises.
- Tissue samples were collected at various time points post-injury.
- mRNA expression of tPA was analyzed using quantitative methods.
- Inflammatory cell infiltration (neutrophils, macrophages, lymphocytes) and epidermal thickening were assessed histologically.
Main Results:
- Neutrophils were detected from 1 hour, macrophages from 3 hours, and lymphocytes from 144 hours post-injury.
- Epidermal thickening was observed from 72 hours post-injury.
- tPA mRNA expression peaked at 1 hour and showed a slight increase at 72 hours, with detection in various cell types including neutrophils and macrophages at specific time points.
Conclusions:
- Time-dependent expression of tPA mRNA and inflammatory cell dynamics correlate with histologic changes in bruises.
- These markers are potentially useful for estimating the age of bruises.
- tPA likely plays a significant role in the initial phase of tissue remodeling during bruise healing.
