Objective:To detect the contents of brain water, Na + , and K + and the permeability of blood brain barrier (BBB) of the rats with brain edema in traumatic brain injury (TBI) complicated by seawater drowning(SWD) at different time points, so as to analyze the time course changes of brain edema after the combined injury. Methods:A total of 216 SD rats were randomly divided into control group ( n=6), sham operation group ( n=14), TBI group ( n=98), and TBI+ SWD group ( n=98). The TBI + SWD rat models were created on the basis of Marmarou′s weight-drop TBI modeling and instilling seawater into the trachea by syringe pump. Dry-wet mass method was used to detect the content of brain water. Flame spectrophotometry method was used to detect the contents of Na + and K + . Evans blue (EB) staining method was used to detect BBB permeability. Results:In the TBI group, the contents of brain water and Na + began to rise obviously 12 h after injury, reached the peak 2-3 d after injury, and returned to the normal levels 14 d after injury. The content of K + showed a fall 12 h after injury, reached the lowest point in 2-3 d after injury, and was still at a lower level than normal in 7 d. The EB content showed double peaks in 3 h and 2 d after injury respectively, and the latter peak was higher. Compared with those in the TBI group, the contents of brain water, Na + , and EB in the TBI + SWD group were significantly increased, but the content of K + was obviously decreased. In the TBI + SWD group, the contents of brain water and Na + began to rise 3 h after injury, reached the peak at 12 h till 7 d after injury, and were still higher than the normal levels 14 d after injury. The content of brain K + showed an obvious fall 3 h after injury, reached the lowest point at 12 h till 3 d, and was still lower than the normal level 7 d after injury. The EB content increased obviously 3 h after injury, reached the peak at 12 h till 3 d after injury, and was still higher than the normal level 14 d after injury. Conclusion:SWD aggravates brain edema in TBI rats. TBI + SWD rats may develop severe cerebral edema in the early period after injury, which last for a longer time.

Objective:To evaluate the effects of mouse nerve growth factor (mNGF) on the brain water content and the expressions of β-amyloid precursor protein (β-APP) and neurofilament light polypeptide (NF-L) in rats with traumatic brain injury (TBI) complicated by seawater drowning (SWD). Methods:A total of 60 male rats were randomly divided into three groups: Sham group ( n=12), TBI+ SWD group ( n=24), and mNGF group ( n=24). The rat models were created on the basis of Marmarou′s weight-drop TBI modeling and instilling seawater into the trachea by syringe pump. The mNGF group was administered mNGF intraperitoneally; while the Sham group and the TBI+ SWD group were injected with an equivalent amount of normal saline. The brain water content was measured by using the dry-wet weight method. The pathological changes of the hippocampal tissue and the expressions of β-APP and NF-L were observed through hematoxylin-eosin (HE) staining and immunohistochemical (IHC) staining. Results:Brain water content in the mNGF group was similar to that in the TBI+ SWD group ( P>0.05). Compared with the TBI+ SWD group, the expressions of β-APP and NF-L in the hippocampal tissue of the mNGF group were significantly reduced. Conclusion:mNGF can reduce the expressions of β-APP and NF-L, and protect the neurons of the rats after TBI+ SWD.

Objective:To detect the contents of brain water, Na + , and K + and the permeability of blood brain barrier (BBB) of the rats with brain edema in traumatic brain injury (TBI) complicated by seawater drowning(SWD) at different time points, so as to analyze the time course changes of brain edema after the combined injury. Methods:A total of 216 SD rats were randomly divided into control group ( n=6), sham operation group ( n=14), TBI group ( n=98), and TBI+ SWD group ( n=98). The TBI + SWD rat models were created on the basis of Marmarou′s weight-drop TBI modeling and instilling seawater into the trachea by syringe pump. Dry-wet mass method was used to detect the content of brain water. Flame spectrophotometry method was used to detect the contents of Na + and K + . Evans blue (EB) staining method was used to detect BBB permeability. Results:In the TBI group, the contents of brain water and Na + began to rise obviously 12 h after injury, reached the peak 2-3 d after injury, and returned to the normal levels 14 d after injury. The content of K + showed a fall 12 h after injury, reached the lowest point in 2-3 d after injury, and was still at a lower level than normal in 7 d. The EB content showed double peaks in 3 h and 2 d after injury respectively, and the latter peak was higher. Compared with those in the TBI group, the contents of brain water, Na + , and EB in the TBI + SWD group were significantly increased, but the content of K + was obviously decreased. In the TBI + SWD group, the contents of brain water and Na + began to rise 3 h after injury, reached the peak at 12 h till 7 d after injury, and were still higher than the normal levels 14 d after injury. The content of brain K + showed an obvious fall 3 h after injury, reached the lowest point at 12 h till 3 d, and was still lower than the normal level 7 d after injury. The EB content increased obviously 3 h after injury, reached the peak at 12 h till 3 d after injury, and was still higher than the normal level 14 d after injury. Conclusion:SWD aggravates brain edema in TBI rats. TBI + SWD rats may develop severe cerebral edema in the early period after injury, which last for a longer time.

Objective:To evaluate the effects of mouse nerve growth factor (mNGF) on the brain water content and the expressions of β-amyloid precursor protein (β-APP) and neurofilament light polypeptide (NF-L) in rats with traumatic brain injury (TBI) complicated by seawater drowning (SWD). Methods:A total of 60 male rats were randomly divided into three groups: Sham group ( n=12), TBI+ SWD group ( n=24), and mNGF group ( n=24). The rat models were created on the basis of Marmarou′s weight-drop TBI modeling and instilling seawater into the trachea by syringe pump. The mNGF group was administered mNGF intraperitoneally; while the Sham group and the TBI+ SWD group were injected with an equivalent amount of normal saline. The brain water content was measured by using the dry-wet weight method. The pathological changes of the hippocampal tissue and the expressions of β-APP and NF-L were observed through hematoxylin-eosin (HE) staining and immunohistochemical (IHC) staining. Results:Brain water content in the mNGF group was similar to that in the TBI+ SWD group ( P>0.05). Compared with the TBI+ SWD group, the expressions of β-APP and NF-L in the hippocampal tissue of the mNGF group were significantly reduced. Conclusion:mNGF can reduce the expressions of β-APP and NF-L, and protect the neurons of the rats after TBI+ SWD.

Objective To investigate the effects of carbamylated erythropoietin (C-EPO) on brain edema in traumatic brain injury (TBI) rats coupled with seawater drowning(SWD).Methods Totally,108 male SD rats were randomly divided into the sham group(n =30),the TBI + SWD group (n =36)and the C-EPO treatment group (n =36).The TBI + SWD rat model was established by using Marmarou brain trauma method (450 g × 1.5 m),coupled with the pumping of artifical seawater into trachea at a rate of 3ml/kg.Following building of the composite model,50 μg/kg of C-EPO or an identical volume of normal saline were injected into the abdomen every 24 hours.Samples of brain tissue were collected at 6,24,72 and 168 hours after surgery.Neurologic impairment and recovery of the rats were evaluated by MNSS.At the same time,pathological changes in the injured brain tissue,water content in the brain tissue,permeability of blood brain barrier (BBB) and the expression of AQP4 were either closely observed or detected.Results Seventy-two hours after surgery,HE staining indicated that brain edema could clearly be observed in the TBI + SWD group,and brain edema in the C-EPO treatment group was obviously less severe,as compared with the TBI + SWD group.As compared with the TBI + SWD group,MNSS scores of the C-EPO treatment group at hours 24,48,72 and 168 all decreased (P ＜ 0.05).Furthermore,brain water content at hours 24,48,72 and 168 after surgery in the C-EPO group all significantly decreased,and EB content at hours 6 and 72 after surgery in the C-EPO group also significantly decreased,as compared with those of the TBI + SWD group(P ＜ 0.05).Besides,the expression levels of AQP4 at hours 6,24,72 and 168 after surgery in the C-EPO group all significantly decreased (P ＜0.05).Conclusion C-EPO has a certain neuroprotective effect by inhibiting traumatic brain edema in the TBI rats coupled with seawater drowning,its potential mechanism might be associated with the expression of AQP4 to resist brain edema.

Objective To explore the role of TLR4/NF-kB signal pathway in rat nerve injury after traumatic brain injury coupled with seawater drowning.Methods A total of 96 male Sprague-Dawley rats were randomly divided into 3 groups:the sham surgery group(n =12),the traumatic brain injury (TBI) group(n =42) and the traumatic brain injury coupled with seawater drowning group (or the TBI + SWD group) (n =42).At the timepoints of 3,6,12,24,72 and 168 hours after the establishment of the TBI model,immunohistochemistry was used to detect the expression of TLR4 and NF-kB cells in the rat brain tissue.Real time PCR (rt-PCR) was applied to detect the expression levels of TLR4 and NF-kB mRNA in the hippocampus of the brain tissue,and enzyme-linked immunosorbent assay (ELISA) was employed to detect the content of TNF-α in the rat brain tissue.Results The number of TLR4 and NF-kB positive cells in the brain tissue of the TBI group and the TBI + searwater drowning group increased.The expressions of TLR4 and NF-kB mRNA in the hippocampus of the brain tissue of the TBI group and the TBI + SWD group significantly increased 3 hours after establishment of the TBI model.For the TBI group,the expressions of TLR4 and NF-kB were respectively (1.63 ±0.52) and (1.52 ±0.41),while in the the TBI + SWD group,the expressions of the above 2 substantce were respectively (4 1.87 ± 0.93) and (1.87 ± 0.93).At hour 24,the expression reached peak.For the TBI group,the expressions of TLR4 and NF-kB were respectively (49.61 ± 0.34) and (4.60 ± 0.51),while for the the TBI + SWD group,the expressions of the above 2 substantces were respectively (16.11 ±0.49) and (5.80 ± 0.52),then they decreased gradually.The expression levels of TNF-α in the TBI group and the TBI + SWD group were found to elevate 3 hours after establishment of the model.TNF-α expression level for the TBI group was (53.68 ± 1.48) ng/L),while the expression level of the same substance for the TBI + SWD group was (60.14 ± 2.06) ng/L.Wave peak appeared at hour 12,and the wave peak for the TBI group was (79.28 ± 2.46) ng/L,while for the TBI + SWD group,it displayed at (103.51 ± 5.53) ng/L.Conclusion Seawater drowning could aggravate nerve inflammatory response mediated by TLR4/NF-kB signal pathway,which might play an important role in the rat brain injury induced by trauma.

Objective To establish an animal model of traumatic brain injury coupled with acute lung injury induced by seawater drowning.Methods A total of 80 male Sprague-Dawley rats were randomly divided into 4 groups:the sham group,the traumatic brain injury (TBI) group,the seawater drowning-induced acute lung injury (SWD-ALI) group and the traumatic brain injury coupled with seawater drowning-induced acute lung injury (TBI + SWD-ALI) group,each consisting of 20 animals.The TBI model group was established with the impact power of 450 g × 1.5 m by the " Marmarou method".The SWD-ALI group was established by pumping the artificial seawater into the rat trachea at a rate of 3 ml/kg.The TBI + SWD-ALI group was established on the basis of TBI.The data of arterial blood gases were detected 10,30,60,120 and 240 minutes after trauma injury.Wet/dry weight of the lung was detected 240min after injury,and pulmonary pathological changes were also observed after HE staining.Pathological changes in the brain tissue after HE staining and the expression levels of/3-APP and NF-L after immunohistochemical (IHC) staining were observed 24 hours after injury.Results The levels of PaO2 after injury during observation period generally displayed an increasing trend in the TBI,the SWD-ALI and the TBI + SWD-ALI groups.The levels of PaO2 10 minutes after injury were the lowest,which were respectively (85.12 ± 2.03) mmHg,(37.75 ± 1.17) mmHg and (33.38 ± 1.92) mmHg,and were obviously lower than that of the sham group (95.25 ± 2.05) mmHg,with statistical significance (P＜0.05).The levels of PaO2 at the time point of 240 minutes after injury reached peak,which were respectively (96.63 ± 1.60) mmHg,(86.13 ± 2.03) mmHg and (77.25 ± 3.33) mmHg,and the levels of PaO2 for the SWD-ALI and TBI + SWD-ALI groups were significantly lower than that of the sham group [(97.50 ± 1.20) mmHg],also with statistical significance (P ＜ 0.05).The levels of PaO2 in the TBI + SWD-ALI group was considerably lower than that of the SWD-ALI group (P ＜ 0.05).The ratios of wet/ dry weight of the lung tissue at the time point of 240 minutes after injury for the SWD-ALI group and the TBI + SWD-ALI group were respectively (7.30 ± 0.16) and (7.34 ± 0.21),which were all obviously higher than those of the sham group (4.81 ±0.18) and the TBI group (4.91 ±0.18),also with statistical significance (P ＜ 0.05).However,no statistical significance could be seen,when comparisons were made between the SWD-ALI and TBI + SWD-ALI groups (P ＞ 0.05).HE staining indicated that such pulmonary pathological lesions as wider alveolar septa,alveolar space fusion,inflammatory cell infiltration in various degrees could be observed in the SWD-ALI and TBI + SWD-ALI groups.In addition,brain tissue HE staining revealed that neuronal cell degeneration in the cortex of the brain tissue could be detected in the TBI,SWD-ALI and TBI + SWD-ALI groups,and immunohistochemical staining indicated that there were positive expressions of β-APP and NF-L in the TBI and TBI + SWD-ALI groups.Conclusion The impact with the power of 450 g × 1.5 m by the "the Marmarou method" followed by pumping of seawater (3 ml/kg) into trachea could establish a stable and reproductive rat model of traumatic brain injury coupled with acute lung injury induced by seawater drowning.

Objective To investigate the effects of carbamylated erythropoietin (C-EPO) on brain edema in traumatic brain injury (TBI) rats coupled with seawater drowning(SWD).Methods Totally,108 male SD rats were randomly divided into the sham group(n =30),the TBI + SWD group (n =36)and the C-EPO treatment group (n =36).The TBI + SWD rat model was established by using Marmarou brain trauma method (450 g × 1.5 m),coupled with the pumping of artifical seawater into trachea at a rate of 3ml/kg.Following building of the composite model,50 μg/kg of C-EPO or an identical volume of normal saline were injected into the abdomen every 24 hours.Samples of brain tissue were collected at 6,24,72 and 168 hours after surgery.Neurologic impairment and recovery of the rats were evaluated by MNSS.At the same time,pathological changes in the injured brain tissue,water content in the brain tissue,permeability of blood brain barrier (BBB) and the expression of AQP4 were either closely observed or detected.Results Seventy-two hours after surgery,HE staining indicated that brain edema could clearly be observed in the TBI + SWD group,and brain edema in the C-EPO treatment group was obviously less severe,as compared with the TBI + SWD group.As compared with the TBI + SWD group,MNSS scores of the C-EPO treatment group at hours 24,48,72 and 168 all decreased (P ＜ 0.05).Furthermore,brain water content at hours 24,48,72 and 168 after surgery in the C-EPO group all significantly decreased,and EB content at hours 6 and 72 after surgery in the C-EPO group also significantly decreased,as compared with those of the TBI + SWD group(P ＜ 0.05).Besides,the expression levels of AQP4 at hours 6,24,72 and 168 after surgery in the C-EPO group all significantly decreased (P ＜0.05).Conclusion C-EPO has a certain neuroprotective effect by inhibiting traumatic brain edema in the TBI rats coupled with seawater drowning,its potential mechanism might be associated with the expression of AQP4 to resist brain edema.

Objective To explore the role of TLR4/NF-kB signal pathway in rat nerve injury after traumatic brain injury coupled with seawater drowning.Methods A total of 96 male Sprague-Dawley rats were randomly divided into 3 groups:the sham surgery group(n =12),the traumatic brain injury (TBI) group(n =42) and the traumatic brain injury coupled with seawater drowning group (or the TBI + SWD group) (n =42).At the timepoints of 3,6,12,24,72 and 168 hours after the establishment of the TBI model,immunohistochemistry was used to detect the expression of TLR4 and NF-kB cells in the rat brain tissue.Real time PCR (rt-PCR) was applied to detect the expression levels of TLR4 and NF-kB mRNA in the hippocampus of the brain tissue,and enzyme-linked immunosorbent assay (ELISA) was employed to detect the content of TNF-α in the rat brain tissue.Results The number of TLR4 and NF-kB positive cells in the brain tissue of the TBI group and the TBI + searwater drowning group increased.The expressions of TLR4 and NF-kB mRNA in the hippocampus of the brain tissue of the TBI group and the TBI + SWD group significantly increased 3 hours after establishment of the TBI model.For the TBI group,the expressions of TLR4 and NF-kB were respectively (1.63 ±0.52) and (1.52 ±0.41),while in the the TBI + SWD group,the expressions of the above 2 substantce were respectively (4 1.87 ± 0.93) and (1.87 ± 0.93).At hour 24,the expression reached peak.For the TBI group,the expressions of TLR4 and NF-kB were respectively (49.61 ± 0.34) and (4.60 ± 0.51),while for the the TBI + SWD group,the expressions of the above 2 substantces were respectively (16.11 ±0.49) and (5.80 ± 0.52),then they decreased gradually.The expression levels of TNF-α in the TBI group and the TBI + SWD group were found to elevate 3 hours after establishment of the model.TNF-α expression level for the TBI group was (53.68 ± 1.48) ng/L),while the expression level of the same substance for the TBI + SWD group was (60.14 ± 2.06) ng/L.Wave peak appeared at hour 12,and the wave peak for the TBI group was (79.28 ± 2.46) ng/L,while for the TBI + SWD group,it displayed at (103.51 ± 5.53) ng/L.Conclusion Seawater drowning could aggravate nerve inflammatory response mediated by TLR4/NF-kB signal pathway,which might play an important role in the rat brain injury induced by trauma.

Objective To establish an animal model of traumatic brain injury coupled with acute lung injury induced by seawater drowning.Methods A total of 80 male Sprague-Dawley rats were randomly divided into 4 groups:the sham group,the traumatic brain injury (TBI) group,the seawater drowning-induced acute lung injury (SWD-ALI) group and the traumatic brain injury coupled with seawater drowning-induced acute lung injury (TBI + SWD-ALI) group,each consisting of 20 animals.The TBI model group was established with the impact power of 450 g × 1.5 m by the " Marmarou method".The SWD-ALI group was established by pumping the artificial seawater into the rat trachea at a rate of 3 ml/kg.The TBI + SWD-ALI group was established on the basis of TBI.The data of arterial blood gases were detected 10,30,60,120 and 240 minutes after trauma injury.Wet/dry weight of the lung was detected 240min after injury,and pulmonary pathological changes were also observed after HE staining.Pathological changes in the brain tissue after HE staining and the expression levels of/3-APP and NF-L after immunohistochemical (IHC) staining were observed 24 hours after injury.Results The levels of PaO2 after injury during observation period generally displayed an increasing trend in the TBI,the SWD-ALI and the TBI + SWD-ALI groups.The levels of PaO2 10 minutes after injury were the lowest,which were respectively (85.12 ± 2.03) mmHg,(37.75 ± 1.17) mmHg and (33.38 ± 1.92) mmHg,and were obviously lower than that of the sham group (95.25 ± 2.05) mmHg,with statistical significance (P＜0.05).The levels of PaO2 at the time point of 240 minutes after injury reached peak,which were respectively (96.63 ± 1.60) mmHg,(86.13 ± 2.03) mmHg and (77.25 ± 3.33) mmHg,and the levels of PaO2 for the SWD-ALI and TBI + SWD-ALI groups were significantly lower than that of the sham group [(97.50 ± 1.20) mmHg],also with statistical significance (P ＜ 0.05).The levels of PaO2 in the TBI + SWD-ALI group was considerably lower than that of the SWD-ALI group (P ＜ 0.05).The ratios of wet/ dry weight of the lung tissue at the time point of 240 minutes after injury for the SWD-ALI group and the TBI + SWD-ALI group were respectively (7.30 ± 0.16) and (7.34 ± 0.21),which were all obviously higher than those of the sham group (4.81 ±0.18) and the TBI group (4.91 ±0.18),also with statistical significance (P ＜ 0.05).However,no statistical significance could be seen,when comparisons were made between the SWD-ALI and TBI + SWD-ALI groups (P ＞ 0.05).HE staining indicated that such pulmonary pathological lesions as wider alveolar septa,alveolar space fusion,inflammatory cell infiltration in various degrees could be observed in the SWD-ALI and TBI + SWD-ALI groups.In addition,brain tissue HE staining revealed that neuronal cell degeneration in the cortex of the brain tissue could be detected in the TBI,SWD-ALI and TBI + SWD-ALI groups,and immunohistochemical staining indicated that there were positive expressions of β-APP and NF-L in the TBI and TBI + SWD-ALI groups.Conclusion The impact with the power of 450 g × 1.5 m by the "the Marmarou method" followed by pumping of seawater (3 ml/kg) into trachea could establish a stable and reproductive rat model of traumatic brain injury coupled with acute lung injury induced by seawater drowning.