OBJECTIVES: To explore the differences in the repair process of skin and skeletal muscle after contusion caused by blunt force attack with different heights. METHODS: Three degrees of contusion were performed on SD rats' right hind limbs by a designed free-dropping device falling from 15, 30 and 50 cm heights, which as a main consideration factor for degree of injury. The repair process of skin and skeletal muscle at 6 h, 24 h, 3 d, 7 d and 13 d after contusion were observed using routine histological methods. RESULTS: Hematoma within skin and/or muscle was found in the rats' hind limbs after contusion with three different heights. The repair processes were similar at 24 h after contusion. However, with the increase of height, the display degree was more obvious. At 3 d after contusion, the RBC of the hemorrhagic region would be decomposed and elapsed in 15 cm contusion group, but for 30 cm contusion group, it delayed to 7 d. At 13 d after contusion, the similar result was found in 15 cm and 30 cm contusion groups, in contrast, the 50 cm contusion group was still in the proliferative phase. CONCLUSIONS With the increase of height, the occurring rate of hematoma within skin and muscle at the same time increases, and the more serious histological appearance after contusion, including inflammation and proliferation, the longer healing process are observed. According to the results of present study and considering forensic application, the contusion model with 50 cm height （2.58 J/cm²） is recommended as the experimental animal model for the future study of wound age estimation on contusion.
Animals ; Contusions/pathology* ; Hindlimb ; Muscle, Skeletal/pathology* ; Rats ; Rats, Sprague-Dawley ; Skin/pathology* ; Wounds, Nonpenetrating

OBJECTIVE: To establish a new animal model of grading skeletal muscle contusions that could be controllable and repetitive. METHODS: The rats' gastrocnemius was injured by a new weight-dropping device designed. The force acting on gastrocnemius with a comparatively constant duration and inducing elastic deformation of the gastrocnemius was expressed with velocity (v) and deformation (DF). Instant velocity was changed to create gastrocnemius contusions. Pathological changes of gastrocnemius were graded by the gross and histological examinations of 39 rats. RESULTS: At low level of impact (v: 2 m/s, DF: 5.5 mm), mild injuries were detected in epimysium and superficial layer of gastrocnemius. At moderate level of impact (v: 2.5 m/s, DF: 6.5 mm), the injuries were observed in epimysium and whole gastrocnemius. At high level of impact (v: 3 m/s, DF: 7.5 mm), severe injuries were seen deeper to soleus with more extensive skeletal muscle damage. CONCLUSION Grading of skeletal muscle blunt force contusion is created by parameter of velocity and muscle deformation. The model could be used for further research on skeletal muscle contusions.
Animals ; Contusions/classification* ; Disease Models, Animal ; Forensic Pathology ; Male ; Muscle, Skeletal/injuries* ; Rats ; Rats, Sprague-Dawley ; Wounds, Nonpenetrating

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.
Animals ; Contusions/metabolism* ; Follow-Up Studies ; Muscle, Skeletal/pathology* ; Neutrophil Infiltration ; Neutrophils ; Rats ; Rats, Sprague-Dawley ; Time Factors

OBJECTIVE: To analyze the morphological features and forensic pathological characteristics of cardiac ruptures of different causes for their differential diagnosis. METHODS: We analyzed the data of 44 autopsy cases of cardiac rupture from 2014 to 2017 in our institute, including 11 cases caused by blunt violence with intact pericardium, 4 caused by cardiopulmonary resuscitation (CPR), 9 by myocardial infarction, and 20 by aorta dissection rupture.The gross features and histopathological characteristics of cardiac rupture and pericardial effusion were analyzed and compared. RESULTS: Cardiac ruptures caused by blunt violence varied in both morphology and locations, and multiple ruptures could be found, often accompanied with rib or sternum fractures; the volume of pericardial effusion was variable in a wide range; microscopically, hemorrhage and contraction band necrosis could be observed in the cardiac tissue surrounding the rupture.Cardiac ruptures caused by CPR occurred typically near the apex of the right ventricular anterior wall, and the laceration was often parallel to the interventricular septum with frequent rib and sternum fractures; the volume of pericardial blood was small without blood clots; microscopic examination only revealed a few hemorrhages around the ruptured cardiac muscular fibers.Cardiac ruptures due to myocardial infarction caused massive pericardial blood with blood clots, and the blood volume was significantly greater than that found in cases of CPR-induced cardiac rupture ( < 0.05);lacerations were confined in the left ventricular anterior wall, and the microscopic findings included myocardial necrosis, inflammatory cell infiltration, and mural thrombus.Cardiac tamponade resulting from aorta dissection rupture was featured by massive pericardial blood with blood clots, and the blood volume was much greater than that in cases of cardiac ruptures caused by blunt violence, myocardial infarction and CPR ( < 0.05). CONCLUSIONS Hemorrhage, inflammatory cell infiltration, and lateral thrombi around the cardiac rupture, along with pericardial blood clots, are all evidences of antemortem injuries.
Aneurysm, Dissecting ; complications ; Aortic Aneurysm ; complications ; Cardiopulmonary Resuscitation ; adverse effects ; Forensic Pathology ; Heart Rupture ; etiology ; pathology ; Heart Rupture, Post-Infarction ; pathology ; Humans ; Myocardial Contusions ; complications

OBJECTIVE: To study the relationship between the expression of c-Fos protooncogene and skeleton muscle contusion of rats, and to search for a sensitive marker of timing for skeleton muscle contusion. METHODS: Fifty Sprague-Dawley rats were randomly distributed into control group and experimental groups. The expression of c-fos was microscopically observed by immunohistochemical method. RESULTS: With the time prolonged the c-fos positive intensity and area were increased. Positive expression of c-fos protein appeared at 15 min after skeleton muscle contusion, and reached to the peak at 1h after skeleton muscle contusion, then decreased gradually and returned to the normal level on 1d after skeleton muscle contusion. CONCLUSION The detection of the expression of c-fos protein could be a sensitive marker for timing skeleton muscle contusion.
Animals ; Contusions/pathology* ; Female ; Hindlimb/injuries* ; Immunohistochemistry ; Male ; Muscle, Skeletal/pathology* ; Proto-Oncogene Proteins c-fos/biosynthesis* ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Staining and Labeling ; Time Factors

OBJECTIVE: To investigate the expression of caspase-6 in rat skin contusion and its surrounding areas during repairment. METHODS: Immunohistochemical SP method and Western blot technique were used to study the expression and activation of caspase-6 in rat skin contusion and its surrounding areas. RESULTS: Weak expression of caspase-6 was detected in cytoplasms of polymorphonuchear cells (PMNs) infiltrated in the injured area at 3 hours post-contusion. The ratio of the caspase-6 positive cells was low (25.78 +/- 1.38)%. The expression of caspase-6 was increased prominently (47.70 +/- 5.14)% at 12 hours post-contusion. Almost all of the PMNs, mononuclear cells (MNCs) and fibroblastic cells (FBCs) were caspase-6 positive with both cytoplasm and nucleus staining (54.58 +/- 5.64)% on post-contusion day 3. The expression of caspase-6 decreased gradually thereafter. The expression of the 34-kDa pro-caspase-6 was detected by Western blot in both control and the post-contusion groups with time dependent dynamics. CONCLUSION These results suggest that caspase-6 may play a major role in trauma-induced inflammatory response. Since caspase-6 shows a timely dependent expression in PMNs, MNCs and FBCs during skin injury repair in rat, it may be used as a marker for the contusion age determination,
Animals ; Apoptosis ; Blotting, Western ; Caspase 6/metabolism* ; Contusions/pathology* ; Fibroblasts/metabolism* ; Immunohistochemistry ; Male ; Monocytes/metabolism* ; Neutrophils/metabolism* ; Rats ; Rats, Sprague-Dawley ; Skin/pathology* ; Time Factors ; Wound Healing

OBJECTIVE: To evaluate the expression of Bcl-2 protein after brain concussion. METHODS: Expression levels of Bel-2 protein in cortex, pontine and cerebellum of rats were investigated using immunohistochemistry. RESULTS: There was no expression of Bcl-2 protein in control group seen. The expression of Bcl-2 protein in brain concussion groups was detected at l hour, and the expression level reached its peak 4 days after the concussion and then declined gradually. CONCLUSION Our findings suggest that the detection of Bel-2 protein could be an indicator for diagnosis of brain concussion and for estimation of the post injury time interval.
Animals ; Brain/pathology* ; Brain Concussion/metabolism* ; Brain Stem/pathology* ; Cerebral Cortex/pathology* ; Contusions/pathology* ; Disease Models, Animal ; Female ; Immunohistochemistry ; Male ; Neurons/pathology* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Rats ; Rats, Sprague-Dawley ; Time Factors

OBJECTIVE: To explore the general features and the keypoints of forensic medical examination in tumbling injury cases. METHODS: Twenty-eight cases dying of tumbling injury were collected and the locations and features of injury were analyzed. RESULTS: The occiput of head was the common position for the tumbling injury cases. Force, disease and alcohol were the main reasons for tumbling injury. CONCLUSION The injury is mild outside and severe inside from tumbling injury cases. The craniocerebral contrecoup is the significant feature in tumbling injury cases.
Accidental Falls/mortality* ; Adolescent ; Adult ; Aged ; Alcoholism/blood* ; Autopsy ; Cause of Death ; Contusions/pathology* ; Craniocerebral Trauma/pathology* ; Female ; Forensic Pathology ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Scalp/pathology* ; Skull Fractures/pathology* ; Young Adult

A teenaged female was found dead in front of a three story building. Blunt force injuries were found mainly in the right upper-posterior part of the body. Autopsy findings revealed basal skull fracture, multiple rib fractures of the right thoracic cage, both scapular fractures and right iliac bone fracture. Additionally, typical so-called 'tramline'bruises were bilaterally noted at buttocks. The hymen was intact, but showed mucosal hemorrhage. After the personal identity was revealed, the police could find a witness who heard the detailed description of the criminal acts from one of the suspects. According to the witness, the deceased was pushed by two other teenaged girls from the concrete fence of the roof floor after the suspects molested the genitalia of the deceased and beat on the buttocks with a wooden stick. Mathematical estimation of the height of fall based on the severity of injuries correlates with that of the three story building. Authors suggest that a careful examination of injury patterns is required to differentiate homicidal falls from suicidal or accidental ones. Furthermore, application of mathematical model might be helpful to estimate the height of falls or correlate the assumed height of fall with severity of injuries.
Accidental Falls ; Autopsy ; Buttocks ; Contusions ; Criminals ; Female ; Floors and Floorcoverings ; Forensic Pathology ; Fractures, Bone ; Genitalia ; Hemorrhage ; Homicide ; Humans ; Hymen ; Models, Theoretical ; Police ; Rib Fractures ; Skull Fractures ; Wit and Humor as Topic

OBJECTIVE: To map the progression of osteoporosis following spinal cord injury in mice in specific areas and analyze changes in parathyroid hormone (PTH) and ion levels which could be responsible for overall bone loss. SUMMARY OF BACKGROUND DATA: Spinal cord injury rapidly induces severe bone loss compared to other conditions, yet the cause of this bone loss has not been identified. Studies suggest the bone loss after injury is not solely due to disuse. METHODS: To quantify bone loss we weighed individual bones and measured bone mineral density using dual energy X-ray absorptiometry at acute (1 week) and chronic (4 week) time points following a T9 contusion. An ELISA was used to measure blood PTH levels at 1 and 4 weeks after injury. Calcium and phosphate levels were also analyzed at 4 weeks following injury at the University of Miami pathology core. RESULTS: We observed a significant decrease in bone mineral density in hind limbs after an acute injury, and found this bone loss to progress over time. Furthermore, following chronic injury a decrease in bone mineral density is also observed in bones above the level of injury and in the total bone mineral density. We observed a significant decrease in parathyroid hormone levels in injured mice at the chronic time point, but not at the acute time point which suggests this could be involved in the global bone loss following injury. We also observed a significant increase in serum calcium levels following injury which could account for the imbalance of PTH levels.
Absorptiometry, Photon ; Animals ; Bone Density ; Calcium ; Contusions ; Enzyme-Linked Immunosorbent Assay ; Extremities ; Mice* ; Osteoporosis ; Parathyroid Hormone ; Pathology ; Spinal Cord Injuries* ; Spinal Cord*