ABSTRACT
Objective To research the relation between the time-dependent appearances of myofibroblasts during the repair of contused skeletal muscle in rat and wound age determination. Methods A total of 35 SD male rats were divided into the control and six injured groups according to wound age as fol-lows: 12 h, 1 d, 5 d, 7 d, 10 d and 14 d after injury. The appearances of myofibroblasts were detected by HE staining, immunohistochemistry and confocal laser scanning microscopy. Masson’s trichrome staining was utilized to examine collagen accumulation in the contused areas. Results Immunohistochemical stain-ing showed that α-SMA+ myofibroblasts were initially observed at 5 d post-injury. The average ratio of myofibroblasts was highest at 14 d post-injury, with all samples, ratios more than 50%. In the other five groups, the average of α-SMA positive ratios were less than 50%. The collagen stained areas in the contused zones, concomitant with myofibroblast appearance, were increasingly augmented along with ad-vances of posttraumatic interval. Conclusion The immunohistochemical detection of myofibroblasts can be applied to wound age determination. The myofibroblasts might be involved in collagen deposition during the repair of contused skeletal muscle in rat.
ABSTRACT
Objective To study the percentages of polymorphonuclear leukocytes (PMN), mononuclear cells (MNC) and fibroblastic cells (FBC) in different post-traumatic intervals after skeletal muscle me-chanical injury in rats. Methods The rat model of skeletal muscle mechanical injury was established. The rats were divided into injured groups (6 h, 12 h, 1 d, 3 d, 7 d, 10 d and 14 d after injury ) and con-trol group. The percentages of PMN, MNC and FBC in different post-traumatic intervals after skeletal muscle mechanical injury were assessed with HE staining and image analysis. Results At post-injury 6-12 h, the percentages of PMN and MNC infiltration appeared in injured sites and that of PMN reached peak. At 1 d, the percentage of MNC infiltration appeared and reached peak, while that of PMN de-creased. At 3-7 d, the percentage of FBC gradually increased, while that of PMN and MNC decreased. At 10-14 d, the percentage of FBC reached peak. Conclusion The percentages of PMN, MNC and FBC in injured zones showed time-dependent changes, which might be used as reference index for determination of age of skeletal muscle injury.
ABSTRACT
Oncogene c-jun is a member of jun family,the immediately early genes(IEGs),and belongs to one of the nuclear transcription factors of basic leucine zipper(bZIP)family.Combined with many gene promotors,c-jun is involved in the regulation of gene transcription.Its products play important roles in regulating gene expression,cell proliferation,differentiation and apoptosis.The structure,biological funetion,regulation of c-jun and its roles contributing to tissue damage are reviewed in this article,which may provide understanding for severity of tissue injury and wound age estimation in the field of forensic pathology.
ABSTRACT
Focal adhesion kinase(FAK)and extracellular signal-regulated protein kinase(ERK),which are thought to play major roles in transducing surface receptor-derived signals into nucleus,are pivotal signal transduction molecules in mammalian cells.FAK is activated through phosphorylation by extracellular stimuli.p-FAK activates the downstream of ERK which changes cell action.FAK-ERK signal conduction factors are involved in a variety of biological responses,such as cell proliferation,differentiation,stress,apoptosis and malignant change.The biologic characters of FAK-ERK and advances in the study on its roles in tissue damage are reviewed in this article,which may provide a more effective way for estimation of wound age in forensic medicine.