Expression Of HSP70 In Rats With Different Levels Of Closed Brain Injury And Its Significances

Objective:To investigate the expression of HSP70 protein and mRNA in rats with different levels of closed brain injury; To explore the weight-drop device model of graded impact brain injury in rats;Study the significance of HSP70 in different levels of closed brain injury in rats.Methods:1,According to free-fall theory, using different weight from the same height with different impact stress (128.90Kpa, 386.70Kpa, 644.50Kpa) , resulting in mild, moderate and severe closed brain injury model using 54 rats in experimental group and 18 rats in brain sham group.2,Detecting the expression of HSP70 protein changes in different levels brain injury rats by EliVision immunohistochemistry. 3,Doing quantitative analysis in different classes of closed brain injury in rats HSP70mRNA by RT-PCR.Results:1,HE staining showed that in mild group after 3h injury there is hemorrhage in pial subcortical, proliferation in glial cell; and in moderate injury group, there is hemorrhage in superficial cortical, cerebral edema, proliferation in glial cell; while in severe injury group there is cortex extensive bleeding, bleeding peri see neutrophil infiltration, neuronal disappearance, grid-like substance around the brain. 2,Animal model immunohistochemical results showed that HSP70 protein in sham group, mild injury group, moderate injury group and the severe injury group were expressed, the percentage of positive cells were 8.1%, 11.24%, 20.56%, 30.43%; Mild injury group and the control group showed no significant difference between the expression (P>0.05); moderate, and severe injury group and the control group expressed significantly (P <0.05); while there was significant difference between expression in mild, moderate and severe injury group(P <0.05). 3,RT-PCR results showed that HSP70mRNA in the sham group, mild injury group, moderate injury group and the severe injury group were expressed, The ratio of the densitometry of HSP70 and the Densitometry ofβ-actin were 0.330,0.415,0.550,0.767; Mild injury group and the control group showed no significant difference between the ratio (P> 0.05); moderate, and severe injury group and the control group the ratio was significantly (P<0.05); while there was significant difference between expression in mild, moderate and severe injury group(P <0.05).Conclusions:1,HSP70mRNA and protein in neurons under stress injury is consistent, indicating that in a short period of time HSP70mRNA and its protein rate was significantly increased with the severity of injury, the expression difference of HSP70 can be used as a good grade index to moderate closed brain injury in a short time. 2,The model solute the problem of Against parts instability in the classic falling model. This new model is reproducible, and has the practical value in the exploration of closed brain injury in rat experimental study.