Closed head injury in rats: histopathological aspects in an experimental weight drop model / Trauma craniano fechado em ratos: aspectos histopatológicos em um modelo experimental de queda de peso

PURPOSE: To study histopathological findings due to a model of closed head injury by weight loss in rats. METHODS: A platform was used to induce closed cranial lesion controlled by weight loss with a known and predefined energy. 25 male Wistar rats (Rattus novergicus albinus) were divided in five equal groups which received different cranial impact energy levels: G1, G2, G3 and G4 with 0.234J, 0.5J, 0.762J and 1J respectively and G5 (Sham). Under the effect of analgesia, the brain of each group was collected and prepared for histopathological analysis by conventional optic microscopy. RESULTS: It was observed greater number of injured neurons in animals of group 4, however neuronal death also could be noticed in animals of group 5. Intraparenchymal hemorrhages were more frequent in animals of group 4 and the cytotoxic brain swelling and vascular congestion were more intense in this group CONCLUSION: The histopathological analysis of these findings allowed to observe typical cranial trauma alterations and these keep close relation with impact energy.

OBJETIVO: Investigar as alterações histopatológicas produzidas por um modelo de trauma craniano fechado por queda de peso em ratos. MÉTODOS: Utilizando uma plataforma para produção de lesão craniana fechada controlada por queda de peso com energia pré-definida e conhecida, 25 ratos Wistar machos (Rattus norvegicus albinus) foram divididos em cinco grupos iguais que receberam níveis diferentes de energia de impacto craniano: G1, G2, G3 e G4 com 0,234J, 0,5J, 0,762J e 1J respectivamente e G5 (Sham). Sob analgesia, cada grupo teve seus encéfalos coletados e processados para análise histopatológica por microscopia óptica convencional. RESULTADOS: Houve maior número de neurônios lesados em animais do grupo 4, mas morte neuronal também pôde ser constatada nos animais do grupo 5. Hemorragias parenquimatosas foram mais frequentes nos animais do grupo 4 e o inchaço cerebral citotóxico e congestão vascular foram mais intensos neste grupo. CONCLUSÃO: Os achados à análise histopatológica permitem observar alterações típicas do trauma craniano e estas guardaram proporção direta com a energia do impacto.

Analysis on clinical classification and injury certification in 30 cases of acute closed head trauma / 法医学杂志

OBJECTIVE@#In order to improve accuracy of forensic expert conclusion and provide scientific and reasonable accordance for revising identifying criteria for the injury degree, correlation between clinical classification and injury certification of acute closed head trauma were explored.@*METHODS@#A total of 30 cases about acute closed head trauma were selected. Comparison and analysis were made about their differences and the correlation between the clinical classification and the injury degree certification.@*RESULTS@#Mild craniocerebral injury is equal to mild or moderate injury, moderate craniocerebral injury is equivalent to mild or severe injury, severe craniocerebral injury is mostly equivalent to severe injury.@*CONCLUSION@#There are some correlation between the clinical classification and the injury certification in acute closed head trauma. It is necessary to refer to the criteria of clinical classification when revising identifying criteria for the injury degree so as to enhance scientific rigor and rationality.

Expression of caspase-8 after brain injury from fluid percussion in rats / 法医学杂志

OBJECTIVE@#To provide the evidence of the relationship between brain injury and the time of injury.@*METHODS@#Rats were contused on brain by fluid percussion, then were killed after injury for 15 min, 30 min, 1,3,6,12 h, and 1,4,7,14 d respectively. The expression of caspase-8 were detected by immunohistochemical technology on rat brain section and the results were assessed by image analysis system in the cerebral cortex, thalamus, and hippocampus.@*RESULTS@#The expression of caspase-8 in cortex and hippocampus could be detected in 30 min after injury, increased significantly in 3h, reached apex in 1d after injury, remained 4d before decreased. In addition, the expression of caspase-8 can be detected in 1h after injury and reached apex in 1d after injury, and remained 4d then reduced.@*CONCLUSION@#It seems that the expression of caspase-8 should be a useful target for diagnosis of early brain injury.

A study on pathological changes of closed diffuse brain injury in rats with H.E., esterification-silver stain and albumin immunohistochemical stain / 法医学杂志

OBJECTIVE@#To observed the pathological changes of closed diffuse brain injury in the rats died immediately and 15 min to 5 days after the injury.@*METHODS@#H.E. staind and esterification-silver stain were applied to investigate the closed diffuse brain injury.@*RESULTS@#In rats died immediately after the concussive injury, a number of shrunken neurons(type I change), distended neurons(type II change) and wave-like nerve fibers were identified in the brain tissue, especially in brain-stem. At 2 h and 8 h after injury, brain edema and axonal swelling appeared clearly in the cortex and white matter, especially in brain-stem. At post-traumatic 8 h and 24 h, the axonal retraction balls began to appear. The amount of neurons undergoing type I and II changes and constraction balls increased along with the survivor time. After 4 days and 5 days, brain edema alleviated, but the retraction balls and axonal swelling still existed. With Esterifica-tion silver stain, the above changes of neurons and nerve fibers were more obvious. With ABC stain, the distribution of albumin(Al) was extended from the perio-vascular area to diffuse distribution. Al positive staining were more obvious in injuried neurons and nerve fibers.@*CONCLUSION@#The distribution of the concussive damage in the brain are coup, contra-coup and centripental.