| Blast induced traumatic brain injury(bTBI) is a main health issue for numbers of civilians and military populations world-wide as it was a major reason of death and chronic disability. Blast induced traumatic brain injury has the factors as followed: multiple injury、combined injury、multiple tissue injury and condition severity and so on. The death rate is up to 30~40%. There is a very important reason to explore how to heal blast induced traumatic brain injury. In the recent time, the most important difficult is the model of blast induced traumatic brain injury is unstable and the animal survival time is short, which could not apply to the experiment. As the technology fast development and the use of many kinds of new type of weapons, the number of man suffered from blast induced traumatic brain injury is much more than the man who suffered from gunshot during modern war. Blast induced traumatic brain injury has become the research emphasis of modern firearm injury. But there was a main problem in this study of Blast induced traumatic brain injury is how to establish a Blast induced traumatic brain injury animal model. The model animals must be survival an enough long time for the study of pathophysiology and pathomorphology.However, the underlying mechanisms of emodin on protecting Blast induced traumatic brain injury is still remain unclear.In this paper, we firstly establish the Blast induced traumatic brain injury animal model successfully. And then the animal model was stimulated by Emodin to explore the protect effect of emodin on Blast induced traumatic brain injury. We further explored the mechanism of emodin in protect Blast induced traumatic brain injury.1. To establish a new rat model to simulate blast effects on the brain tissue.We developed a reproducible and reliable blast induced traumatic brain injury model in rats successfully, with a specially designed aluminum cabin,and electric detonator( 400 mg TNT).After explosion, the rats could be observed limb seizure, limpness, apnea and poor appetite. Edema and diffuse subarachnoid hemorrhage could be observed within the brain parenchyma, which showed Capillary damage, loss of integrity, and vascular space in cortex and enlarged intercellular, with tattered nerve fiber could be observed.2. The protect effect of Emodin on blast induced traumatic brain injury.2.1 Emodin could reduce the IL-1β in blast induced traumatic brain injury rat brain tissueThe IL-1β production in b TBI rat brain tissue was detected by ELISA. The results showed that the IL-1β production in bTBI rat brain tissue was higher than control group rat. Emodin could reduce the IL-1β production in bTBI rat brain tissue significantly. The result suggested that the rat suffered bTBI could product more IL-1β and Emodin could inhibited this effect.2.2 Emodin could reduce the TNF-a in blast induced traumatic brain injury rat brain tissueThe TNF-a production in bTBI rat brain tissue was detected by ELISA. The results showed that theTNF-a production in bTBI rat brain tissue was higher than control group rat. Emodin could reduce the TNF-a production in bTBI rat brain tissue significantly. The result suggested that the rat suffered bTBI could product more TNF-a and Emodin could inhibited this effect.2.3 Emodin could reduce the water contain in blast induced traumatic brain injury rat brain tissueTo further study the effect of Emodin on the water contain in bTBI rat brain tissue, we assay the water contain in bTBI rat brain tissue by, we detected the water contain by measurement with wet-and-dry-bulb thermometer. The results showed that the water contain in bTBI rat brain tissue was higher than that of control group and the water contain in bTBI rat brain tissuerat was reduced when the times gone. But the water contain is still higher than that of control group. However, Emodin could reduce the water contain in bTBI rat brain tissue. The result suggested that the rat suffered bTBI will suffer hydrocephalus and the Emodin could reduce the effect.2.4 The protect effect of Emodin on blast induced traumatic brain injury.Next HE staining and electron microscopy were used to investigate the potential role of emodin in improving the brain damage after bTBI. HE staining showed that the capillary damage and the intercellular and vascular spaces were enlarged in the cortex, a tattered nerve fiber was observed, and a large number of neurons were lost, suggesting the successful model establishment.3.The mechanism of the protect effect of Emodin on blast induced traumatic brain injury.3.1 Emodin could reduce the TNF-a and IL-1β production in OGD MG cellsWe used different conteins of Emodin to stimulate OGD MG cells and the TNF-a and IL-1β production were detected by ELISA. The results showed that the TNF-a and IL-1β production in OGD MG cells was higher than control group MG cells. Emodin could reduce the TNF-a production and IL-1β production in OGD MG cells significantly. The result suggested that OGD MG cells could product more TNF-a and IL-1β. Emodin could inhibited this effect.3.2 Emodin downregulated the expression of TLR4 on OGD MG cellsTo further explore the relationship of Emodin and TLR4 pathway activation in OGD MG cells, we detected the TLR4 expression on OGD MG cells. The results showed that TLR4 mRNA and protein expression levels were upregulated in OGD MG cells than that of control group, and Emodin downregulated the expression of TLR4 mRNA and protein on OGD MG cells.3.3 Emodin inhibited the TLR4 induced MyD88-dependent pathway activation in OGD MG cellsTo further explore the roles of Emodin in the TLR4 pathway activation of OGD MG cells, we detected the MyD88 expression and IκB phosphorylation related to TLR4 signaling by Western blot and qRT-PCR. The results showed that theMyD88 expression and IκB phosphorylation were both upregulated in OGD MG cells. But Emodin inhibited the MyD88 expression and IκB phosphorylation suggesting that Emodin inhibited the TLR4 induced MyD88-dependent pathway activation in OGD MG cells.3.4 Emodin decreased the productions of IL-1β and TNF-a by inhibiting MyD88-dependent pathway induced by TLR4 in OGD MG cellsTo further explore the roles of TLR4 in the productions of IL-1β and TNF-a, the TLR4 expression of OGD MG cells was blocked with anti-TLR4 antibody before stimulating with Emodin. We detected the IL-1β and TNF-a productions level by ELISA. The results showed that the levels of IL-1β and TNF-a productions in OGD MG cells were higher than that of control group, and Emodin decreased IL-1β and TNF-a secretion of OGD MG cells. Moreover, we found that Emodin could not decrease IL-1β and TNF-a secretion of OGD MG cells which were pre-treated with anti-TLR4 antibody. Next, we treated OGD MG cells used the same way and detected the MyD88 expressionandIκB phosphorylation related to TLR4 signaling by Western blot. The results showed that the MyD88 expression and IκB phosphorylation levels were higher than that of control group, and Emodin decreased MyD88 expression and IκB phosphorylation levels of OGD MG cells. However, Emodin could not decrease MyD88 expression and IκB phosphorylation levels of OGD MG cells which were pre-treated with anti-TLR4 antibody.In one words, our study firstly used the blast induced traumatic brain injury animal model which was established by our team before. The animal model of bTBI applied us a well condition for the following experiment. Next, we detected the protected role of Emodin on Traumatic brain injury. We confirmed that the Emodin could inhibied IL-1β and TNF-a productions and then played an important role in protecting the bTBI. Finally, we could get the conclusion that Emodin could play an important role in protecting the bTBI via inhibiting the activation of MyD88 pathway induced by TLR4, and then inhibited the IL-1β and TNF-a productions in OGD MG cells. |
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