Research Progress of Metabolomics Techniques Combined with Machine Learning Algorithm in Wound Age Estimation / 法医学杂志

Wound age estimation is the core content in the practice of forensic medicine. Accurate estimation of wound age is a scientific question that needs to be urgently solved by forensic scientists at home and abroad. Metabolomics techniques can effectively detect endogenous metabolites produced by internal or external stimulating factors and describe the dynamic changes of metabolites in vivo. It has the advantages of strong operability, high detection efficiency and accurate quantitative results. Machine learning algorithm has special advantages in processing high-dimensional data sets, which can effectively mine biological information and truly reflect the physiological, disease or injury state of the body. It is a new technical means for efficiently processing high-throughput big data. This paper reviews the status and advantages of metabolomic techniques combined with machine learning algorithm in the research of wound age estimation, and provides new ideas for this research.

Application of Linear Regression Model of Gpnmb Gene in Rat Injury Time Estimation / 法医学杂志

OBJECTIVES@#To investigate the effects of injury time, postmortem interval (PMI) and postmortem storage temperature on mRNA expression of glycoprotein non-metastatic melanoma protein B (Gpnmb), and to establish a linear regression model between Gpnmb mRNA expression and injury time, to provide aimed at providing potential indexes for injury time estimation.@*METHODS@#Test group SD rats were anesthetized and subjected to blunt contusion and randomly divided into 0 h, 4 h, 8 h, 12 h, 16 h, 20 h and 24 h groups after injury, with 18 rats in each group. After cervical dislocation, 6 rats in each group were collected and stored at 0 ℃, 16 ℃ and 26 ℃, respectively. The muscle tissue samples of quadriceps femoris injury were collected at 0 h, 12 h and 24 h postmortem at the same temperature. The grouping method and treatment method of the rats in the validation group were the same as above. The expression of Gpnmb mRNA in rat skeletal muscle was detected by RT-qPCR. The Pearson correlation coefficient was used to evaluate the correlation between Gpnmb mRNA expression and injury time, PMI, and postmortem storage temperature. SPSS 25.0 software was used to construct a linear regression model, and the validation group data was used for the back-substitution test.@*RESULTS@#The expression of Gpnmb mRNA continued to increase with the prolongation of injury time, and the expression level was highly correlated with injury time (P<0.05), but had little correlation with PMI and postmortem storage temperature (P>0.05). The linear regression equation between injury time (y) and Gpnmb mRNA relative expression (x) was y=0.611 x+4.489. The back-substitution test proved that the prediction of the model was accurate.@*CONCLUSIONS@#The expression of Gpnmb mRNA is almost not affected by the PMI and postmortem storage temperature, but is mainly related to the time of injury. Therefore, a linear regression model can be established to infer the time of injury.

Application Prospect of MicroRNA in Skin Wound Age Estimation / 法医学杂志

Wound age estimation is one of the major tasks in forensic practice. However, relatively accurate estimation of the wound age is still a conundrum and research spotlight world-widely. Studies show that microRNAs (miRNAs) are involved in the whole process of the skin wound repair, and miRNAs, as biomarkers, might be used to estimate the time of skin injury owing to their characteristic advantage. This paper summarizes the miRNA fundamental function, properties, current research progress in the estimation of wound age, and its limitations, and put forward prospect of potential application and research based on miRNAs in estimation of wound age.

Application of Immunohistochemistry and Special Staining Technique in Forensic Traumatic Pathology Identification / 法医学杂志

In forensic traumatic pathology practice, immunohistochemistry and special staining technique play an important role in wound age estimation and complications of traumatic complication identification. They even play an important role in the identification of special cases, such as snakebites and insulin killings. This article reviews the application and value of immunohistochemistry and special staining techniques in forensic traumatic pathology based on the cases of forensic practice reported in literature.

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.

Expression of Nrf2 in Different Cells after Human Cerebral Cortex Contusion / 法医学杂志

Objective To observe the expression changes of nuclear factor-erythroid derived 2-related factors （Nrf2） in different cells at different time points after human cerebral cortex contusion, and to discuss its application in brain wound age estimation. Methods Thirty-six human brain tissues were selected, of which 6 were for control and 30 were cortical contusion at different time points post-injury, which were divided into 0-1 h, 3-6 h, 1-3 d, 5-7 d, and 10-14 d post-injury groups, with 6 cases in each group. Based on paraffin embedded sections, HE staining was used to observe the morphological changes post-injury, and double immunofluorescence staining was used to detect the expression of Nrf2 in neurons, astrocytes, and microglia. The number of positive cells was counted and statistical analysis was made. Results The number of neurons decreased 1-3 d post-injury. The expression of Nrf2 cells in neurons increased after injury, and the rate of positive cells peaked at 1-3 d post-injury. Glial cells were activated 1-3 d post-injury, and the activation peaked at 5-7 d post-injury. The cerebromalacia began to form at 10-14 d post-injury. Glial fibrillary acidic protein （GFAP） positive cells in mice increased gradually after injury and peaked at 5-7 d post-injury, while the proportion of Nrf2 in GFAP positive cells was relatively stable. After injury, ionized calcium-binding adapter molecule 1 （IBA1） positive cells increased and activated gradually. The expression proportion of Nrf2 in IBA1 positive cells increased gradually, reached its peak at 5-7 d post-injury, and then decreased. Conclusion The expression of Nrf2 in different cells involves in the biological function of different cells post-injury, and the dynamic expression of single cells has a time-dependent pattern. This may provide a new reference index for the wound age estimation of brain contusion in human.

Relationship between Changes of Pericyte Number and Wound Age during Repair of Skeletal Muscle Contusion in Mice / 法医学杂志

Objective To observe the change pattern of pericyte number at different time periods after mice skeletal muscle contusion and discuss its role in wound age estimation. Methods A mice gastrocnemius muscle contusion model was established. The form and number changes of pericytes at 1, 3, 5, 7, 9, 14, and 28 d post-injury were detected by multiple immunofluorescence staining. Results Compared with the slender shape of pericytes in normal skeletal muscles, pericytes in the contusion area had increased volume, rounder form and a round nuclei. Part of pericytes were found to express satellite cell markers paired-box transcription factor （Pax7） or myoblast determination 1 （MyoD1）. The changes of pericyte number in skeletal muscles after contusion were time-dependant, and showed unimodal distribution with the extension of wound age. In the central contusion area, the number of pericytes peaked at 5 d post-injury while in the peripheral contusion area, the number of pericytes peaked at 5 d and 7 d post-injury. Conclusion The number of pericytes in contusion area varies time-dependently after skeletal muscle contusion in mice and might be a reference index for muscle wound age estimation, and is involved in the repair and regeneration of skeletal muscle injury.

Wound Age Estimation by Neutrophil Migration Distance / 法医学杂志

Objective To explore the application of neutrophil migration distance for wound age estimation of skeletal muscles in rats, and to provide methodological basis for follow-up study in future. Methods The skeletal muscle contusion model was established in rats, and the control group and the 2, 4, 6 h post-traumatic groups were set. The law of response of neutrophils that participated in the inflammation after injury was detected by immunohistochemical staining, and the relationship between neutrophil migration distance and injury time was detected by TissueFAXS PLUS software. Results The skeletal muscle was obviously infiltrated with neutrophils 2-6 h after injury. The positive rate of neutrophil was （28.75±0.94）% at 2 h post-traumatic, and reached the peak （45.50±3.63）% at 4 h post-traumatic, then decreased to （31.92±1.56）% at 6 h post-traumatic. The neutrophil migration distances increased with the progress of inflammation, and reached （124.80±12.32） μm, （229.03±21.45） μm and （335.04±16.75） μm at 2 h, 4 h and 6 h, respectively. Conclusion There is a relationship of neutrophil infiltrated number and migration distance and wound age within the 2-6 h after skeletal muscle injury, which could be used for the inference of skeletal muscle wound age.

Combination of mRNA of Repair-related Genes in Rat Skeletal Muscles for Wound Age Estimation / 法医学杂志

Objective To investigate the estimation of early and mid-term wound age by a combination of four mRNAs, the DNA polymerase delta-interacting protein 3 （POLDIP3） mRNA, regulator of chromosome condensation 1 like （RCC1L） mRNA, proline-rich 5 （PRR5） mRNA, and ribonucleic acid export 1 （RAE1） mRNA in rats skeletal muscles. Methods The model of rat skeletal muscle contusion was established, and then contusion area muscle tissue was extracted 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44 and 48 h after injury. Histomorphological changes during the repair process after rat skeletal muscle contusion were observed. The relative expressions of Poldip3, Rcc1l, Prr5 and Rae1 mRNAs were detected by reverse transcription real-time quantitative polymerase chain reaction （RT-qPCR）. Different stages of wound age were classified by using the expression patterns of four genes at various time points after injury. The accuracy of the results was verified by Fisher discriminant analysis. Results Histomorphological results showed that the repair process after skeletal muscle contusion occurred with the prolonging of time. Through combination of the expression trends of the four kinds of mRNAs, the 48 h after injury could be divided into three periods, 4-12 h, 16-28 h and 32-48 h. The Fisher discrimination method showed that the classification accuracy rates of the three periods were 83.3%, 75.0% and 73.3%, respectively. Conclusion The classification discrimination based on the relative expression of every gene has a higher accuracy, and the accuracy of wound age estimation with combination of mRNA relative expressions is higher than that with a single indicator. By combining with Fisher discrimination method, this method can be used for early and mid-term wound age estimation.

Expressions of TGF-β1 and EⅢA-FN after Rat Skeletal Muscle Contusion and Wound Age Estimation / 法医学杂志

Objective To study the expressions of transforming growth factor-β1 （TGF-β1） and EⅢA-fibronectin （EⅢA-FN） at different time points of antemortem injury, antemortem injury postmortem expression and postmortem injury and to explore their application value in wound age estimation. Methods A model of rat skeletal muscle contusion was established. The rats were randomly divided into normal control group （n=5）, antemortem contusion group （n=40）, antemortem contusion postmortem expression group （n=110） and postmortem injury group （n=25）. The expressions of TGF-β1 and EⅢA-FN after rat skeletal muscles antemortem contusion were detected with immunohistochemical staining. Expression changes of TGF-β1 and EⅢA-FN mRNA in each group were analyzed with real-time fluorescence quantitative PCR. Results Immunohistochemical staining results showed that a large number of polymorphonuclear leukocyte, mononuclear cells and fibroblastic cells showed a strong expression of TGF-β1 in wounded zones 12 h-14 d after antemortem contusion. EⅢA-FN was mainly distributed in the extracellular matrix, 3 to 7 d post-traumatic. Real-time fluorescence quantitative PCR results showed that TGF-β1 and EⅢA-FN mRNA in antemortem injury group reached the peak at 3 and 5 d post-traumatic respectively. The expressions of TGF-β1 and EⅢA-FN mRNA in antemortem contusion postmortem expression group peaked at 6 h and 12 h postmortem. The expression of TGF-β1 and EⅢA-FN mRNA in postmortem injury group 0.5-12 h postmortem was significantly lower than those of the normal control group and the antemortem contusion group. Conclusion TGF-β1 and EⅢA-FN might become a reference index for skeletal muscle wound age estimation.

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.

Relationship between Expression Changes of CB2R and Wound Age of Brain Contusion in Mice / 法医学杂志

Objective To investigate the expression of cannabinoid type 2 receptor （CB2R） at different time points after brain contusion and its relationship with wound age of mice. Methods A mouse brain contusion model was established with PCI3000 Precision Cortical Impactor. Expression changes of CB2R around the injured area were detected with immunohistochemical staining, immunofluorescent staining and Western blotting at different time points. Results Immunohistochemical staining results showed that only a few cells in the cerebral cortex of the sham operated group had CB2R positive expression. The ratio of CB2R positive cells gradually increased after injury and reached the peak twice at 12 h and 7 d post-injury, followed by a decrease to the normal level 28 d post-injury. The results of Western blotting were consistent with the immunohistochemical staining results. Immunofluorescent staining demonstrated that the changes of the ratio of CB2R positive cells in neurons, CB2R positive cells in monocytes and CB2R positive cells in astrocytes to the total cell number showed a single peak pattern, which peaked at 12 h, 1 d and 7 d post-injury, respectively. Conclusion The expression of CB2R after brain contusion in neurons, monocytes and astrocytes in mice suggests that it is likely to be involved in the regulation of the biological functions of those cells. The changes in CB2R are time-dependent, which suggests its potential applicability as a biological indicator for wound age estimation of brain contusion in forensic practice.

Time-dependent Expression of Nrf2 Protein and its Effects on Wound Repair in Skeletal Muscle / 法医学杂志

Objective To detect the expression of nuclear factor erythroid 2-related factor 2(Nrf2)to explore its change rule and effects in the repair process of skeletal muscle. Methods An injury model of skeletal muscle was established by injection of cardiotoxin into the gastrocnemius muscle of SD male rats. The muscle samples were taken from control group and injury group at each time point(1 h, 4 h, 8 h, 12 h, 16 h, 1 d, 3 d, 5 d, 7 d, 9 d, 13 d, 17 d, 21 d). The morphological changes of skeletal muscle in repair process were observed by H&E staining, and the content of reactive oxygen species(ROS)was detected. The expression level of Nrf2 protein was investigated by Western blotting and immunohisto-chemistry staining. Results After the skeletal muscle injury, the injury region was infiltrated with inflam-matory cells which constituted mainly by lymphocyte neutrophils and mononuclear cells. There were large amounts of immature muscle cells appeared at the 5th day and the muscle repair was completed at the 21th day. Comparing with control group, the ROS content decreased in injury group at the 12th hour(P<0.05), while Nrf2 expression increased at the 16th hour(P<0.05). Moreover, the positive rate of Nrf2 increased after injury, and peaked at 16 h-1 d, then decreased gradually and returned to the level of control group(P<0.05). Conclusion The Nrf2 protein involves in the regulation of the repair of skeletal muscle injury. The positive rate of Nrf2 shows a time-dependent expression, which can be used to esti-mate the wound age of skeletal muscle.

Homogeneity of Different Functional mRNA Indicators for Wound Age Estimation / 法医学杂志

OBJECTIVES@#To explore the homogeneity level of four different functional mRNA （PUM2, TAB2, Cx45 and CHRNA1） expressions in rats with skeletal muscle contusion.@*METHODS@#The relative expressions of PUM2, TAB2, Cx45 and CHRNA1 mRNAs were detected by quantitative real-time reverse transcription-polymerase chain reaction （RT-qPCR）. The coefficient of variation （CV） of the relative expressions for different individuals in each injury group was calculated. The extreme value of CV, cumulative variability, and CVCV were compared.@*RESULTS@#A high CV of PUM2 and TAB2 mRNAs appeared on several different time points. However, the CV of Cx45 and CHRNA1 mRNAs was relatively low. The cumulative variability from high to low was PUM2, CHRNA1, TAB2 and Cx45 mRNAs. The relative expression of PUM2 mRNA was significantly higher than that of TAB2, Cx45 and CHRNA1 mRNAs （ P<0.05）. There was no statistical significance （P>0.05） in the CVCV of the relative expression of TAB2, CHRNA1 and Cx45 mRNAs.@*CONCLUSIONS@#As the mRNAs involving in biological process regulation, PUM2 and CHRNA1 mRNAs show a lowest individual homogeneity of the relative expression followed by TAB2 mRNA. As the mRNAs participating in the composition of cellular structure, Cx45 and CHRNA1 mRNAs show a high individual homogeneity of the relative expressions. The functional classification should be considered for the screening of the mRNA indicators used for wound age estimation.

Time-dependent Expression of MT1A mRNA and MT2A mRNA in the Contused Skeletal Muscle of Rats / 法医学杂志

OBJECTIVES@#To investigate the time-dependent expression of metallothionein （MT） 1A mRNA and MT2A mRNA in contused skeletal muscle of rats.@*METHODS@#A total of 54 Sprague-Dawley rats were used in this study. The rats were divided into two parts: control group （n=6） and contusion groups （0.5, 1, 6, 12, 18, 24, 30, and 36 h after contusion, n=6）. Total RNA was extracted from skeletal muscle. The expression levels of MT1A mRNA and MT2A mRNA were detected by SYBR Green I real-time PCR.@*RESULTS@#The expression trends of the two potential marker genes were related to wound age. In addition to 0.5 h, there were significant contrasts between the control group and contused group （P<0.05）, about the expression levels of MT1A mRNA and MT2A mRNA in different phases. As the extension of wound age, the relative expression of MT1A mRNA and MT2A mRNA at 1 h, 6 h, 12 h and 18 h after contusion demonstrated upgrade tendency until its expression levels in 18 h peak with 239.41±15.20 and 717.42±50.76, respectively. When time extends to 24 h after injury, the expression of above two marks decreased, respectively. The MT1A mRNA and MT2A mRNA expression levels increased at 30 h and then decreased.@*CONCLUSIONS@#Determination of MT1A mRNA and MT2A mRNA levels by real-time PCR may be useful for the estimation of wound age.

Relationship between Wound Age and the Expression of Fzd2 in Rats Skeletal Muscle after Contusion / 法医学杂志

Objective To investigate the relationship between wound age and the expressions of frizzled-2 (Fzd2) mRNA and its protein in rats skeletal muscle after contusion,and to explore its possibility of being an index for wound age estimation.Methods The mRNA and protein expressions of Fzd2 in rats skeletal muscle of the control group and the experimental group within 4-48 h after contusion were detected per 4 h by RT-qPCR and Western blotting.Results The relative expression of Fzd2 mRNA increased at 24h,36h and 40h after contusion,and the expression at 24h was twice as the control group (P＜0.05).The relative expression of Fzd2 protein changed inconspicuously after contusion (P＞0.05).Conclusion The changes of Fzd2 mRNA expression after contusion in a certain time can be a basis to estimate wound age by combined multi-indicators.

Time-dependent expression of FZD4 in contused skeletal muscle of rat used for wound age estimation / 中国法医学杂志

Objective Take frizzled class receptor 4(FZD4) as an example for exploring whether the transmembrane receptor protein is a suitable marker for wound age estimation. Methods A total of 78 Sprague-Dawley rats were divided randomly into the control group and the contusion groups of 4h, 8h, 12h, 16h, 20h, 24h, 28h, 32h, 36h, 40h, 44h, and 48h after injury (n=6). Using a drop-ball technique, a contusion was produced in the right lamb of rats. The samples were dissected from injury zones. Then the expression of FZD4 was detected using immunofluorescence, real-time PCR and western blot, respectively. Results FZD4 was located on the membrane of skeletal muscle cells. Compared to the control group, FZD4 mRNA showed a signiifcant increase (over 2-fold) in 8h, 12h, 36h, and 40h after injury by Real-time PCR (P<0.05), and FZD4 protein showed a statistical up-regulation (less than 2-fold) in 8h, 36h, 40h, 44h, and 48h post contusion by western blotting (P<0.05). Conclusion The expression of FZD4 mRNA and protein are both time-dependent during contused skeletal muscle repair. To some degree, FZD4 mRNA was more suitable than corresponding protein for determining wound age.

An immunohistochemical study on the time-dependent expression of IL-10 and IL-4 during skin incised wound healing in mice / 中国法医学杂志

Objective To explore the temporal expressions of interleukin-10(IL-10)and interleukin-4(IL-4)and their relationship with the wound age during skin incised wound healing in mice.Methods Immunohistochemical and image-analysis techniques were employed in vital skin wounds 0.5h～168h after incision and postmortem incision 0.5h～6h after death.Results Weak expression of IL-10 was detected at 0.5h after incision,which increased subsequently,and peaked at 3h post-injury.Then decreased to the pre-incision level at 24h,but peaked again at 72h after injury.Immunostaining revealed that epidermal cells and infiltrating mononuclear cells were the major source of IL-10.IL-4-positive cells were observed in the dermis at 24h,and reached the maximum level at 96h,which maintained until 168h post-injury.IL-4 was mainly expressed in the fibroblast-like cells of the granulation tissue and dermis.In addition,faint IL-10-positive cells were merely identified in the epidermal cells in the postmortem incision skin within 1～3h after incision.No IL-4-postitive cells were found in the postmortem incision skin.Conclusion The time-dependent expressions of IL-10 and IL-4 during cutaneous wound healing may be used for the estimation of wound age.

An immunohistochemical study on COX-1 and COX-2 following traumatic brain Injury in rats / 中国法医学杂志

Objective The time-dependent changes of COX-1 and COX-2 following the experimental brain contusion were studied for the purpose of extrapolation of the molecular mechanism and timing of brain contusion.Methods Male SD rats were divided into normal control,sham-operated control and contusion groups.The animal model of cerebral contusion was established by impact to the parietal lobe with a free fall weight.The time-dependent changes of COX-1 and COX-2 were detected at 1d,3d,5d,7d,14d post-injury by immunohistochemical SP method.Results In comparison with the control,COX-1 and COX-2 were faintly expressed in the brain of the control groups.Expression of COX-1 was gradually elevated in the cortex of the brain from 1d to 5d after contusion,which was sustained at a high level up to 14d postinjury.Expression of COX-2 was gradually increased in the cortex of the brain from 1d to 3d after injury,which peaked in the hippocampus at 1d after contusion.Conclusion It is suggested that brain contusion may induce the expressions of the COX-1 and COX-2,and the time-dependent changes of COX-1 and COX-2 may be applicable to the wound age estimation of cerebral contusion in forensic practice.