Function of IL-33 in Wound Age Estimation of Skin Wounds in Mice / 法医学杂志

Objective To explore the application value of interleukin-33 （IL-33） in wound age estimation in forensic practice by observing the sequential changes of IL-33 after skin wound. Methods Skin wound models were generated on the back of mice with a round file of 5 mm in diameter. Skin samples of the same size were taken from the same parts of mice in control group and injury group 1 h, 3 h, 6 h, 12 h, 1 d, 3 d, 5 d, 7 d and 10 d after skin wound. Hematoxylin-eosin （HE） staining method was applied to observe the morphological changes in the recovering process after skin wound. Western blotting, immunohistochemistry staining and double immunofluorescence staining methods were applied to detect the expression changes of IL-33 in the skin wound samples. Results The results of Western blotting showed that the expression of IL-33 protein decreased slightly at 3 h after skin wound, increased gradually at 6 h after skin wound, and reached the peak value at 3 d, then decreased gradually. Immunohistochemistry staining results showed that faint positive expression of IL-33 was observed in epidermis, hair follicles, sebaceous glands and dermal resident cells of the control group skin. The positive cell rate of IL-33 increased at 3 h after skin wound and reached the peak value at 3 d, then decreased gradually. The results of double immunofluorescence staining showed that the majority of IL-33 positive cells from 1 d to 3 d after wound were macrophages, while the majority of IL-33 positive cells from 5 d to 7 d after wound were myofibroblasts. In addition, the results of HE staining showed that the wound healing process of the skin wound model was consistent with the pathological development law of inflammation. Conclusion IL-33 could become a reference index for wound age estimation of skin wound in forensic practice.

Application of Virtual Anatomy Technology in Postmortem Examination of Medical Dispute Cases / 法医学杂志

Objective To discuss the application value of CT scanning technology in cause of death determination of medical dispute cases. Methods From July 2017 to December 2018, postmortem CT imaging data of 12 medical dispute cases were collected. CT imaging diagnosis results and anatomy findings as well as differences between antemortem and postmortem CT diagnosis were compared. The advantages and disadvantages of CT routine tests of the cadavers in terms of the diagnosis of disease and damage were analyzed. Results The comparison between CT imaging diagnosis and anatomical findings showed that CT scans had advantages in the diagnosis of disease and damage with large differences in density changes, such as atelectasis, pneumonia, calcification, fracture and hemorrhage, etc. The comparison of CT diagnosis in antemortem and postmortem examination showed that the cadavers of medical dispute cases were well preserved and that postmortem CT scan was meaningful for the diagnosis of antemortem diseases. Conclusion Virtual anatomy technology has a relatively high application value in postmortem examination of medical dispute cases. It can provide effective information for the appraisers before the autopsy and can also provide a reference for cause of death analysis when the anatomy cannot be performed.

Relationship between the Number of Neutrophils and Myofibroblasts during Diabetic Wound Healing and Wound Age / 法医学杂志

Objective To investigate the sequential changes of the number of neutrophils and myofibroblasts during diabetic wound healing, and discuss its application value in wound age estimation. Methods Diabetic DB mice and mice of the same age in the normal control group were selected, a wound healing model was established, wound samples were taken at different time points, while the number of neutrophils and myofibroblasts during diabetic wound healing were determined by immunohistochemical staining technique. Results The number of infiltrated neutrophils in the wounds of control and diabetic groups reached the peak respectively at 12 h and 5 d after injury. Compared with the control group, the number of neutrophils in the diabetic group decreased significantly from 6 h to 1 d after injury, but increased markedly from 5 d to 14 d. From 5 d to 10 d after injury, the average number of neutrophils at high magnification in wounds of the diabetic group was over 30, while that of neutrophils in wounds of the control group was less than 20. Myofibroblasts appeared in wounds from 3 d to 14 d after injury in the control group and from 5 d to 14 d after injury in the diabetic group. The difference in the number of myofibroblasts in wounds between control group and diabetic group from 3 to 7 d after injury had statistical significance. Conclusion In comparison with normal wound healing, the number of neutrophils and myofibroblasts during diabetic wound healing shows different sequential changes. The results of this study can provide reference for wound age estimation of patients with severe diabetes.

Time-dependent Expression and Distribution of AChE during the Skin Incised Wound Healing in Mice / 法医学杂志

Objective To study the time-dependent expression and distribution of acetylcholinesterase （AChE） during skin incised wound healing in mice, and discuss its effect in wound healing as well as the feasibility of using it as a reference index for wound age estimation. Methods A total of 45 C57BL/KsJ mice were randomly divided into one control group and eight incised groups. The skin incised wound model was established in the incised groups with samples of skin wounds taken at 6 h, 12 h, 1 d, 3 d, 5 d, 7 d, 10 d and 14 d post-injury respectively, while the uninjured skin tissue was extracted in the control group. Expression and distribution of AChE in skin samples were detected by immunohistochemistry, double immunofluorescence and Western blotting. Results Immunohistochemistry results indicated that AChE was mainly detected in infiltrating polymorphonuclear cells （PMNs） 6 to 12 h post-injury. A large number of AChE-positive mononuclear cells （MNCs） were observed 1 to 3 d post-injury. The AChE-positive cells were mainly fibroblastic cells （FBCs） 5 to 14 d post-injury. The ratio of the AChE-positive cells increased initially 6 h post-injury, and reached the peak at 1 d post-injury. Double immunofluorescent staining showed that the majority of AChE-positive MNCs and FBCs expressed macrophage marker and myofibroblast marker, respectively. Western blotting results showed that the relative expression level of AChE in the incised group was higher than that in the control group averagely, reached the peak at 1 d post-injury, then reached a second peak at 7 d post-injury. Conclusion The expression of AChE is found in PMNs, macrophages and myofibroblast during skin wound healing, which indicates it might be involved in the adjustment of inflammatory response and fibrotic repair after injury. Moreover, combined use of various methods for the detection of the expression of AChE would provide reference for skin 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.