Relationship between Wound Age and Serum Marker Metabolites of Rats Skin Incised Wound / 法医学杂志

Objective To observe the metabolomics changes of serum after skin incision of rats and to determine the wound age of skin incision. Methods A rat skin incision model was established, 21 SD rats were divided into 1 h, 2 h, 4 h, 8 h, 16 h, 24 h after skin incision groups and the control group, then blood was taken from rats in the experimental groups at the corresponding time points after injury, and taken from the control group directly. Gas chromatography-mass spectrometry （GC-MS） technology was used to detect serum metabolites and screen marker metabolites, then orthogonal partial least square-discriminant analysis （OPLS-DA） model was used to establish a regression model for the relationship between marker metabolite content and wound age to determine wound age of skin. Results GC-MS was used to detect the serum collected, and 21 marker metabolites were obtained through initial screening, and 4 marker metabolites were further analyzed and screened using multivariate statistical analysis methods. There was no correspondence between the change rule of the serum content and wound age, therefore it cannot be used directly to determine wound age. OPLS model could be used to obtain regression models of the content and wound age of 21 marker metabolites and 4 marker metabolites, both of which can determine wound age, but the prediction accuracy of the regression model of 21 marker metabolites was significantly higher. Conclusion Using metabolomics to establish a regression model of the metabolite content and wound age has the potential to be applied to skin incision wound age determination.

Relationship between the Degeneration and Regeneration of Neuromuscular Junction and Wound Age during the Repair of Mouse Skeletal Muscle Contusion / 法医学杂志

Objective To investigate the morphological changes in the degeneration and regeneration of neuromuscular junctions （NMJ） during the repair of mouse skeletal muscle contusion and discuss the correlation between the degeneration and regeneration of NMJ and wound age. Methods A total of 50 healthy adult male mice were randomly divided into 10 groups, including 9 experimental groups and 1 control group. Immunofluorescent staining was applied, and neurofilament was marked with neurofilament protein-H （NF-H）, presynaptic membrane was marked with synaptophysin （Syn）, presynaptic membrane was marked with acetylcholine receptor （AChR）. Morphological changes of NMJ regeneration at different time points after mouse skeletal muscle contusion were detected. Results The neurofilament and presynaptic membrane of NMJ at the junction of contusion zones began to degrade after contusion, and completed degradation at about 3 d post-injury. Then they gradually regenerated, roughly completing the regeneration at about 21 d and basically reaching the control group level. The ratio of presynaptic membrane quantity to presynaptic membrane quantity showed a trend of decreasing then rising and finally reaching the control level. Conclusion During the repair of mouse skeletal muscle contusion, the morphological changes and wound age of the NMJ at the junction of contusion zones have a close correlation, which is expected to be one of the biological indicators for forensic skeletal muscle wound age estimation.

Expression of Annexin A1 during Skin Incised Wound Healing in Mice / 法医学杂志

OBJECTIVES@#To investigate the expression changes of annexin A1 （ANXA1） during the process of skin incision healing, and to explore its expression and function during skin injury repair.@*METHODS@#The skin injury model of mice was prepared, and skin tissues of the controls and the injured group at 6 h, 12 h, 1 d, 3 d, 5 d, 7 d, 10 d and 14 d after injuries were taken. The morphological changes of the wound were observed by hematoxylin-eosin （HE） staining, and the expression of ANXA1 was detected by immunohistochemistry （IHC） and Western blotting.@*RESULTS@#HE staining showed normal healing of skin wounds. IHC results revealed that ANXA1 was expressed in the epidermis, hair follicle, sebaceous gland and vascular endothelium. In the injured group, the expression of ANXA1 was enhanced in epidermis and skin appendages around the wound 6-12 h after injury, and ANXA1 was also highly expressed in neutrophils and a small number of mononuclear cells. ANXA1 was mainly positively expressed in monocytes, neovascular endothelial cells and fibroblasts, and small amount of fibroblasts at 1-3 d, 5-10 d, and 14 d after injury, respectively. Western blotting showed that, compared with the controls, the expression of ANXA1 was significantly increased at 6 h after injury, peaked at 1 d, and then decreased gradually in the injured group.@*CONCLUSIONS@#ANXA1 may be involved in the regulation of skin damage repair, with time-dependent expression during skin wound healing, and thus is expected to be a biological marker for inferring the wound formation time.

Relationship between FoxO1 Expression and Wound Age during Skin Incised Wound Healing / 法医学杂志

Objective To investigate FoxO1 expression and its time-dependent changes during the skin incised wound healing. Methods After the establishment of the skin incised wound model in mice, the FoxO1 expression of skin in different time periods was detected by immunohistochemistry and Western blotting. Results Immunohistochemistry staining showed that FoxO1 was weakly expressed in a few fibroblasts of epidermis, hair follicles, sebaceous glands, vessel endothelium and dermis in the control group. The FoxO1 expression was enhanced in the epidermis and skin appendages around the wound during 6-12 h after injury, which could be detected in the infiltrating neutrophils and a small number of monocytes. FoxO1 was mainly expressed in monocytes during 1-3 d after injury, and in neovascular endothelial cells and fibroblasts during 5-10 d. On the 14th day after injury, the FoxO1 expression still could be detected in a few fibroblasts. The Western blotting results showed that the FoxO1 expression quantity of the tissue samples in injury group was higher than in control group. The FoxO1 expression peaked at 12 h and 7 d after injury. Conclusion FoxO1 is time-dependently expressed in skin wound healing, which can be a useful marker for wound age determination.

An immunohistochemical study on the expressions of caspase-6、-7 during the skin incised wound healing in mice / 中国法医学杂志

Objective To investigate the expressions of caspase-6,-7 during skin wound healing and the applicability of the time-dependent expressions of caspase-6,-7 to determination of the wound age.Method The expressions of caspase-6,-7 were studied in skin incised wound in mice by immunohistochemical SABC method,and the non-incised mouse skin was used as control.Results Expressions of caspase-6,-7 were detectable in polymorphonuclear cells (PMNs) in the wound specimens aged 6h. In the wound specimens aged from 12h to 24h after injury, caspase-6,-7 were identified in a large number of infiltrating PMNs and part of mononuclear cells (MNCs). Afterwards, the MNCs and fibroblastic cells (FBCs) accounted for the most part of the caspase-6,-7-positive cells. Morphometrically, the ratios of the number of the caspase-6,-7-stained PMNs, MNCs and FBCs to total number of the cells in the wounds were evaluated and calculated. The ratios of the caspase-6,-7-positive cells were low in the wound specimens aged from 0h to 3h, and maximized in the wound specimens aged 3 day. Thereafter, the ratios decreased and minimized in the specimens aged 14 day.Conclusion The results suggest that caspase-6,-7 were expressed in neutrophils, macrophages and fibroblasts during healing process of skin incised wound in mice. Caspase-6,-7 may be used as a marker for the wound age determination.

An immunohistochemical study on the temporal expression of interleukin-8 in the incised and stabbed wounds in human skin / 中国法医学杂志

To explore the applicability of interleukin 8(IL 8)to determination of wound age in the incised and stabbed human skin samples,an immunohistochemical study on the temporal expression of IL 8 was performed on 52 human skin wounds at different posttraumatic intervals.Expression of IL 8 was detectable in polymorphonuclear cells(PMNs)in the wound specimens aged 4h.In the wound specimens aged from 12～24h after injury,IL 8 was identified in a large number of infiltrating PMNs and part of mononuclear cells(MNCs).Afterwards,the MNCs and fibroblastic cells(FBCs)accounted in the most part of the IL 8 positive cells.Morphometrically,the ratio of the number of the IL 8 stained PMNs,MNCs and FBCs to total number of the cells in the wounds was evaluated and calculated.The ratio of the IL 8 positive cells was low in the wound specimens aged 4 and 6h(16 0?10 1%),and maximized in the wound specimens aged between 1 and 4 days(59 6%?8 7%).Thereafter,the ratio decreased and minimized in the specimens aged from 19 to 21 days(27 5?5 9%).The results suggest that IL 8 can be used as a marker for the wound age determination in both incised and stabbed human skin.