| Background and Objective: Primary brain stem injury, a very important cause at the death of craniocerebral injury, is due to the violence mostly. The clinical signs show coma, twitch, cornea reflex disappear and changes of breath and heart rate. The pathological changes chiefly show the contusion and hemorrhage in brain stem, or no specific change. The reticular structure is the important part of brain stem. Which is relative to the breath, blood vessel contraction and relaxation and heart modulation. Even the slight brain stem injury can lead to the sudden death. The first chief symptom is the impaired breath and blood circulation. Distinct change appeared in the reticular structure after the brain stem injury. Previous reports showed that ultrastructure changes could be observed 10 minutes after mechanical brain stem injury. So the change in brain stem reticular structure is important for studying the mechanism of brain stem derived sudden death.Brain injury can induce two converse changes, in one hand, it can induce to produce plenty of harmful factors, on the other hand, it also can induce to activate the self-repair mechanism of central nervous system to synthesize endogenous protective cytokine. In brain research, much attention has been paid to endogenous protective neural factor. Endogenetic growth factors are some of multifunctional mitotic reagent with strong stimulatingactivity to neuron, glial cell, fibroblast and endothelial cells. Chief physiological functions of endogenetic growth factors are to enhance growth of blood vessle, tissue regeneration and repair. Macrophage and other cells can release endogenetic growth factors after trauma or at some diseases. The purposes of this study was to research the expressions of some endogenetic growth factors and its expression characteristic in reticular structure after brain-stem injury.Material and methods: Rats were randomly divided to the three groups: control group, brain-stem injury group and posthumous injury group. The rats of the brain stem injury group were knocked according to Deng's method and further divided into 7 groups: immediate death, 1-hour, 3-hour, 3-day, 7-day, 10-day, and 14-day after trauma. Rats of the posthumous injury group were knocked after killed 5-minutes and 10-minutes respectively. When the rat was dead after knocked or killed, its brain was sampled at once and fixed by formaldehyde solution for 24 hours, cut into equal halves by the median sagittal suture. Tissue samples were processed routinely such as dehydration, embeded by paraffin and sectioned(5 y. m). Tissue sections were stained with hematoxylin-eosin and SABC immunohistochemical method. Four visual fields were randomly chosen in reticular formation under low objective microscope and the positive cells were counted under 40 times. HPIAS-1000 I AS was used to analyze the gray scale of positive cells. All data were processed by SPSS 10.0 statistic software. One way ANOV was used. Result: Clinical Observation:After knocked, rats in brain-stem injury group appeared the signs of transient stop of breath and heart beat, cornea reflex disappear, twitch, upright tail, etc. Irregular breath and heart beat appeared after 5~10 seconds, heart rate became slow. Irregular heart rhythm appeared, breath become slow and deep. Nine of them died in 60 minutes after knocking. The others were still alive with stable breathe and heart beat. Macropathological Change and Hematoxylin-Eosin staining:Rats in brain-stem injury group appeared no distinct contusion in CNS. One of the rats that died in 60 minutes appear bone fracture in brain. Five of them in the brain stem group appeared little hemorrhage in subarachnoid space. No distinct high brain pressure and no distinct hematoma appeared. Hematoxylin-Eosin staining showed diffuse sheet-like and dot-like hemorrage and slight oedema in brain stem. Rats in control group and postmortem injury group showed no distinct change. SABC Immimohistochemical Staining and Statistic Analysis:In the control group and postmortem injur... |
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