Experimental Research On Neuroinflammation After Traumatic Brain Injury With Seawater Drowning

Objective To investigate the variation of tumor necrosis factor-alpha(TNF-?)and Interleukin-8(IL-8)in rat brain tissue after traumatic brain injury accompanied with seawater drowning.And to elucidate the role of this variation.Materials and methods Totally 84 male Sprague-Dawley rats were randomly divided into 3 groups using a random number table,including sham-operated group(n=8),traumatic brain injury group(n=38)and traumatic brain injury accompanied with seawater drowning group(n=38).The traumatic brain injury was established by Marmarou's model,and the seawater drowning model was produced according to the method that seawater water(3 ml/kg)was instilled into the rat lungs via the trachea in 3 min at a steady speed using a terufusion syringe pump.At 6h post-traumactic brain injury,hematoxylin-eosin staining(HE)was used to observe the pathological changes of brain tissue and lung tissue of the rats in each rats groups,And at 3h,6h,12 h,24h,72 h and 168 h post-traumactic brain injury,enzyme-linked immunosorbent assay(ELISA)was employed to detect the content of TNF-? and IL-8 in rats brain tissue.Results 1.Neuronal cell swelling,shrinkage,degeneration and gap between cells extended could be seen under macroscopy and light microscope in the pathologic changes of rat brain of raumatic brain injury accompanied with seawater drowning group in 6h post injury.And pulmonary interstitial edema,alveolar septum fracture,red blood cells and inflammatory cells infiltration also could be seen in the rat lungs.2.TNF-? has a high expression in post-trauma brain tissue.Compared with the sham-operated group,the expression of TNF-? was significantly increased in the brain tissues of traumatic brain injury group and traumatic brain injury with seawater drowning-lung injury group post-trauma(P<0.05).Further more,the expression of TNF-?,in the composite model at 3h,6h,12 h,24h,72 h post-trauma,were significantly higher than the TBI alone(P<0.05).3.There has a significant increase of the expression of IL-8 in traumatic brain injury with seawater drowning group.Compared with the sham-operated group,the expression of IL-8 was significantly increased in the post-trauma brain tissues(P<0.05).Moreover,the expression of IL-8 was significantly higher in the brain tissues of traumatic brain injury with seawater drowning group than TBI group(P<0.05).Conclusions Seawater drowning-lung injury upregulate the expression of the TNF-? and IL-8 in brain tissue of traumatic brain injury in rat.The neuroinflammation may play a significant role in rat nerve injuries after traumatic brain injury accompanied with seawater drowning.Objective To investigate the effect of toll-like receptor 4 / nuclear factor-k B(TLR4 / NF-k B)signaling pathway on rat nerve injuries after traumatic brain injury accompanied with seawater drowning.Materials and methods Totally 90 male Sprague-Dawley rats were randomly divided into 3 groups using a random number table,sham-operated group(n=14),traumatic brain injury group(n=38)and traumatic brain injury accompanied with seawater drowning group(n=38).The traumatic brain injury was established by Marmarou's model,and the seawater drowning model was produced according to the method that seawater water(3 ml/kg)was instilled into the rat lungs via the trachea in 3 min at a steady speed using a terufusion syringe pump.At 3h,6h,12 h,24h,72 h and 168 h post-traumactic brain injury,modified neurologic severity scale(m NSS)was used to measure the neurological function of all the rats in each rats groups,immunohistochemistry was used to detect the expression of TLR4 and NF-k B positive cells in rats' brain tissue,real time PCR(RT-PCR)was employed to detect the TLR4 and NF-k B expression of TLR4 and NF-k B in RNA level.Results 1.The m NSS has a significant increase in traumatic brain injury accompanied with seawater drowning group.There has a significant increase of m NSS scores,in the traumatic brain injury group and traumatic brain injury with seawater drowning group,compare with the sham group(P<0.05).Further more,the scores of m NSS,in the composite model at 6h,12 h,24h,and 72 h post-trauma,were significantly higher than the TBI alone(P<0.05).2.TLR4 and NF-k B has a high expression in post-trauma brain tissue.Compared with the sham-operated group,the number of TLR4 and NF-k B positive cells were significantly increased in the brain tissues of traumatic brain injury group and traumatic brain injury with seawater drowning group,at 24 h post-trauma.Further more,the number of TLR4 and NF-k B positive cells,in the composite model at 7d post-trauma,were significantly higher than the TBI alone.3.There has a significant increase of the m RNA expression of TLR4 and NF-k B in traumatic brain injury with seawater drowning group.Compare with the sham-operated group,the m RNA expression of TLR4 and NF-k B were significantly increased in the post-trauma brain tissues(P<0.05).More over,the m RNA expression of TLR4 and NF-k B were significantly higher in the brain tissues of traumatic brain injury with seawater drowning group than TBI group(P<0.05).Conclusions Seawater drowning-lung injury aggravate the degree of nerve function defect of traumatic brain injury via upregulating the TLR4/NF-k B signaling pathway in rat traumatic brain injury.And the TLR4/NF-k B signaling pathway may play an important role in rat nerve injuries after traumatic brain injury accompanied with seawater drowning.