A cannabinoid type 2 receptor agonist attenuates blood–brain barrier damage and neurodegeneration in a murine model of traumatic brain injury

After traumatic brain injury (TBI), inflammation participates in both the secondary injury cascades and the repair of the CNS, both of which are influenced by the endocannabinoid system. This study determined the effects of repeated treatment with a cannabinoid type 2 receptor (CB₂R) agonist on blood–brain barrier integrity, neuronal degeneration, and behavioral outcome in mice with TBI. We also looked for the presence of a prolonged treatment effect on the macrophage/microglial response to injury. C57BL/6 mice underwent controlled cortical impact (CCI) and received repeated treatments with a CB₂R agonist, 0‐1966, or vehicle. After euthanasia at 6 hr or 1, 2, 3, or 7 days postinjury, brains were removed for histochemical analysis. Blood–brain barrier permeability changes were evaluated by using sodium fluorescein (NaF). Perilesional degenerating neurons, injury volumes, and macrophage/microglia cells were quantified by stereological methods. Rota‐rod and open‐field testing were performed to evaluate motor function and natural exploratory behavior in mice. 0‐1966 Treatment resulted in a significant reduction in NaF uptake and number of degenerating neurons compared with the vehicle‐treated group. 0‐1966‐Treated mice demonstrated improvement on rota‐rod and open‐field testing compared with vehicle‐treated mice. These changes in CCI mice treated with 0‐1966 were associated with a prolonged reduction in macrophage/microglia cell counts. In conclusion, repeated treatments with a CB₂R agonist, 0‐1966, result in attenuated blood–brain barrier disruption and neuronal degeneration. In addition, repeated treatment with 0‐1966 shows prolonged treatment effects on behavior and the macrophage/microglia cell response over several days. © 2012 Wiley Periodicals, Inc.     

Acute effects of human protein S administration after traumatic brain injury in mice

Despite years of effort, no effective acute phase treatment has been discovered for traumatic brain injury. One impediment to successful drug development is entangled secondary injury pathways. Here we show that protein S, a natural multifunctional protein that regulates coagulation, inflammation, and apoptosis, is able to reduce the extent of multiple secondary injuries in traumatic brain injury, and therefore improve prognosis. Mice subjected to controlled cortical impact were treated acutely(10–15 minutes post-injury) with a single dose of either protein S(1 mg/kg) or vehicle phosphate buffered saline via intravenous injection. At 24 hours post-injury, compared to the non-treated group, the protein S treated group showed substantial improvement of edema and fine motor coordination, as well as mitigation of progressive tissue loss. Immunohistochemistry and western blot targeting caspase-3, B-cell lymphoma 2(Bcl-2) along with terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL) assay revealed that apoptosis was suppressed in treated animals. Immunohistochemistry targeting CD11 b showed limited leukocyte infiltration in the protein S-treated group. Moreover, protein S treatment increased the ipsilesional expression of aquaporin-4, which may be the underlying mechanism of its function in reducing edema. These results indicate that immediate intravenous protein S treatment after controlled cortical impact is beneficial to traumatic brain injury prognosis. Animal Use Protocols(AUPs) were approved by the University Committee on Animal Resources(UCAR) of University of Rochester Medical Center(approval No. UCAR-2008-102 R) on November 12, 2013.     

Moderate hypothermia reduces blood-brain barrier disruption following traumatic brain injury in the rat

Summary The effects of moderate hypothermia on blood-brain barrier (BBB) permeability and the acute hypertensive response after moderate traumatic brain injury (TBI) in rats were examined. TBI produced increased vascular permeability to endogenous serum albumin (IgG) in normothermic rats (37.5°C) throughout the dorsal cortical gray and white matter as well as in the underlying hippocampi as visualized by immunocytochemical techniques. Vascular permeability was greatly reduced in hypothermic rats cooled to 30°C (brain temperature) prior to injury. In hypothermic rats, albumin immunoreactivity was confined to the gray-white interface between cortex and hippocampi with no involvement of the overlying cortices and greatly reduced involvement of the underlying hippocampi. The acute hypertensive response in normothermic rats peaked at 10 s after TBI (187.3 mm Hg) and returned to baseline within 50 s. In contrast, the peak acute hypertensive response was significantly (P<0.05) reduced in hypothermic rats (154.8 mm Hg, 10 s after TBI) and returned to baseline at 30 s after injury. These results demonstrate that moderate hypothermia greatly reduces endogenous vascular protein-tracer passage into and perhaps through the brain. This reduction may, in part, be related to hypothermia-induced modulation of the systemic blood pressure response to TBI.Supported by Grants NS 12587 (BGL), NS 29469 (JTP), NS 19550 (LWJ) from the National Institutes of Health and Grant H133B80029 (BGL) from the National Institute on Disability and Rehabilitation Research, the U.S. Department of Education     

Changes in blood-brain barrier permeability to large and small molecules following traumatic brain injury in mice

The entry of therapeutic compounds into the brain and spinal cord is normally restricted by barrier mechanisms in cerebral blood vessels (blood-brain barrier) and choroid plexuses (blood-CSF barrier). In the injured brain, ruptured cerebral blood vessels circumvent these barrier mechanisms by allowing blood contents to escape directly into the brain parenchyma. This process may contribute to the secondary damage that follows the initial primary injury. However, this localized compromise of barrier function in the injured brain may also provide a 'window of opportunity' through which drugs that do not normally cross the blood-brain barriers are able to do so. This paper describes a systematic study of barrier permeability in a mouse model of traumatic brain injury using both small and large inert molecules that can be visualized or quantified. The results show that soon after trauma, both large and small molecules are able to enter the brain in and around the injury site. Barrier restriction to large (protein-sized) molecules is restored by 4-5 h after injury. In contrast, smaller molecules (286-10,000 Da) are still able to enter the brain as long as 4 days postinjury. Thus the period of potential secondary damage from barrier disruption and the period during which therapeutic compounds have direct access to the injured brain may be longer than previously thought.     

大鼠脑挫裂伤半暗带水肿与血-脑屏障破坏的关系

目的研究大鼠局灶性脑挫裂伤半暗带的水肿变化与血-脑屏障(BBB)破坏的关系。方法将126只雄性SD大鼠随机分为3组:假手术组、挫裂伤组和给药组,采用Feeney法制作脑挫裂伤模型,给药组采用曲克芦丁脑蛋白水解物合剂腹腔给药,分别用伊文思蓝(EB)染色法和干湿法观察BBB的变化和脑组织的水肿情况,同时电镜观察超微结构。结果EB染色显示:挫裂伤组和给药组在伤后1 h EB开始漏出,6 h最严重。水含量测定结果显示:挫裂伤组和给药组伤后6 h水含量开始增加,72 h增至高峰。与挫裂伤组比较,给药组脑组织EB溢出量、水含量降低(P<0.05)。结论大鼠脑挫裂伤半暗带BBB通透性改变早于脑水肿的发生,提示BBB破坏可能是早期创伤性脑水肿的结构基础。曲克芦丁脑蛋白水解物合剂可通过改善BBB等多种途径治疗脑挫裂伤。     

Neuroprotective effects of geranylgeranylacetone in experimental traumatic brain injury

Geranylgeranylacetone (GGA) is an inducer of heat-shock protein 70 (HSP70) that has been used clinically for many years as an antiulcer treatment. It is centrally active after oral administration and is neuroprotective in experimental brain ischemia/stroke models. We examined the effects of single oral GGA before treatment (800 mg/kg, 48 hours before trauma) or after treatment (800 mg/kg, 3 hours after trauma) on long-term functional recovery and histologic outcomes after moderate-level controlled cortical impact, an experimental traumatic brain injury (TBI) model in mice. The GGA pretreatment increased the number of HSP70⁺ cells and attenuated posttraumatic α-fodrin cleavage, a marker of apoptotic cell death. It also improved sensorimotor performance on a beam walk task; enhanced recovery of cognitive/affective function in the Morris water maze, novel object recognition, and tail-suspension tests; and improved outcomes using a composite neuroscore. Furthermore, GGA pretreatment reduced the lesion size and neuronal loss in the hippocampus, cortex, and thalamus, and decreased microglial activation in the cortex when compared with vehicle-treated TBI controls. Notably, GGA was also effective in a posttreatment paradigm, showing significant improvements in sensorimotor function, and reducing cortical neuronal loss. Given these neuroprotective actions and considering its longstanding clinical use, GGA should be considered for the clinical treatment of TBI.     

Downregulation of UBE2Q1 is associated with neuronal apoptosis in rat brain cortex following traumatic brain injury

Aberrant functionality of the ubiquitin proteasome system (UPS) has been implicated in the pathology of various neurological disorders. Although it has been reported that the expressions of various UPS components were altered significantly following traumatic brain injury (TBI), detailed information on the subject remains largely unclear. In the study, using microarray assay, we identified a gene encoding ubiquitin‐conjugating enzyme E2Q1 (UBE2Q1) that was significantly downregulated during TBI. Western blot and immunohistochemical analyses verified the reduced expression of UBE2Q1 in ipsilateral brain cortex adjacent to the lesion site compared with the contralateral and sham‐operated ones. Double‐immunofluorescence staining indicated that UBE2Q1 was expressed mainly in the nucleus of neurons, with a minority in astrocytes in normal cortex. In addition, we observed a remarkable reduction in the number of UBE2Q1‐positive neurons following brain trauma. Furthermore, we showed that TBI resulted in a significant increase in the levels of p53, bax, p21 and active caspase 3 in brain cortex, which was correlated with decreased expression of UBE2Q1. We also found that knockdown of UBE2Q1 apparently increased the level of p53, whereas overexpressing UBE2Q1 attenuated cellular p53 level in PC12 neuronal cells. Accordingly, interference with UBE2Q1 augmented H₂O₂‐induced apoptosis of PC12 cells. Taken together, our findings indicate that UBE2Q1 might play an important role in the neuropathological process of TBI through modulating p53 signaling. © 2013 Wiley Periodicals, Inc.     

Inhibition of nitric oxide synthase aggravates brain injury in diabetic rats with traumatic brain injury

Studies have shown that hyperglycemia aggravates brain damage by affecting vascular endothelial function. However, the precise mechanism remains unclear. Male Sprague-Dawley rat models of diabetes were established by a high-fat diet combined with an intraperitoneal injection of streptozotocin. Rat models of traumatic brain injury were established using the fluid percussion method. Compared with traumatic brain injury rats without diabetic, diabetic rats with traumatic brain injury exhibited more severe brain injury, manifested as increased brain water content and blood-brain barrier permeability, the upregulation of heme oxygenase-1, myeloperoxidase, and Bax, the downregulation of occludin, zona-occludens 1, and Bcl-2 in the penumbra, and reduced modified neurological severity scores. The intraperitoneal injection of a nitric oxide synthase inhibitor N(5)-(1-iminoethyl)-L-ornithine(10 mg/kg) 15 minutes before brain injury aggravated the injury. These findings suggested that nitric oxide synthase plays an important role in the maintenance of cerebral microcirculation, including anti-inflammatory, anti-oxidative stress, and anti-apoptotic activities in diabetic rats with traumatic brain injury. The experimental protocols were approved by the Institutional Animal Care Committee of Harbin Medical University, China(approval No. ky2017-126) on March 6, 2017.     

G蛋白偶联受体30在大鼠蛛网膜下腔出血后对神经炎症和血脑屏障破坏的影响

目的 探讨G蛋白偶联受体30（GPR30）在大鼠蛛网膜下腔出血（SAH）早期脑损伤（EBI）过程中对神经炎症和血脑屏障（BBB）破坏的影响。方法 36只雄性大鼠随机分为6组（n = 6/组）：假手术（Sham）组,SAH（3 h、6 h、12 h、24 h、72 h）组。此外,72只大鼠随机分为4组（n = 18/组）：Sham组、SAH组、SAH联合过表达GPR30慢病毒阴性载体（SAH+Lv-NC）组、SAH联合过表达GPR30慢病毒载体（SAH+Lv-GPR30）组。通过血管内穿孔建立SAH模型,于SHA大鼠脑室内注射Lv-GPR30。通过神经学评分、脑组织含水量（BWC）检测、伊文思蓝（EBP）染色、苏木精和伊红（HE）染色来分析GPR30对EBI的影响;采用蛋白质印迹法（Western blotting）和实时荧光定量PCR（qRT-PCR）分析各种蛋白质和转录水平;通过酶联免疫吸附测定法（ELISA）分别测定肿瘤坏死因子α（TNF-α）、白细胞介素6（IL-6）、白细胞介素1β（IL-1β）、白细胞介素10（IL-10）水平。结果 SAH大鼠脑内注射Lv-GPR30后脑组织中GPR30的表达增加,并改善了大鼠神经功能、神经炎症、BBB破坏和脑水肿程度。过表达GPR30抑制SAH大鼠脑组织中基质金属蛋白肽酶9（MMP-9）和基质金属蛋白肽酶2（MMP-2）的表达,以及炎症因子TNF-α、IL-6、IL-1β表达水平,同时提高IL-10的表达水平。结论 GPR30能减轻SAH大鼠的神经炎症和BBB破坏。 [国际神经病学神经外科学杂志, 2024, 51(2): 29-34]     

Rapid loss and partial recovery of neurofilament immunostaining following focal brain injury in mice

Neurofilaments (NF), the intermediate filaments of the neuronal cytoskeleton, provide mechanical stability to the cell. High-molecular-weight NF (NFH) comprises a heavily phosphorylated carboxyl terminal ("sidearm") domain which helps determine interfilament spacing distances. Experimental evidence suggests that dephosphorylation greatly increases the rate and extent of proteolysis of NFH. Because NF proteolysis has been implicated as one pathogenic mechanism underlying cell death following traumatic brain injury (TBI), we analyzed the patterns of acute NFH damage in relation to phosphorylation state following focal, concussive, controlled cortical impact (CCI) brain injury in mice. Brains from C57BL/6 male mice (n = 4 injured and n = 1 sham per time point) were evaluated 5 min, 15 min, 90 min, 4 h, and 24 h following CCI injury (1 mm depth, 5 m/s). Immunohistochemistry was performed using antibodies that recognize epitopes on either dephosphorylated (d-NFH) or phosphorylated (p-NFH) sidearms or on the core (c-NFH) domain. As early as 5-15 min postinjury, immunoreactivity for d-, p-, and c-NFH decreased in the ipsilateral cortex, and hippocampal CA3, CA1, and dentate areas. This marked decrease of NFH labeling occurred in the absence of notable cell loss. Furthermore, partial recovery of NFH labeling was observed as early as 90 min postinjury in the cortex and by 24 h postinjury in hippocampal CA3 and dentate. The results of this study suggest that both phosphorylated and dephosphorylated NFH are vulnerable almost immediately following focal brain injury in mice, but that injured neurons may have an adaptive capability to partially restore this important cytoskeletal protein.     

黄体酮对创伤性脑损伤大鼠神经细胞凋亡的影响

目的 观察黄体酮对脑外伤后神经细胞凋亡的影响,探讨其对脑外伤(TBI)继发性脑损伤是否存在保护作用.方法 雄性Wistar 大鼠随机分为无脑损伤的假手术(sham)组、脑损伤(TBI)组、脑损伤后注射黄体酮治疗(P-TBI)组及注射二甲基亚砜(DMSO)溶剂(D-TBI)组,每大组24 只,再分1 d、3 d、5 d 和7 d 四个小组,每小组6 只.采用Freeney 法造成鼠脑挫裂伤模型,在伤后四个不同时相点用TUNEL 染色法分别检测四组大鼠脑组织中神经细胞凋亡情况.结果 创伤性脑损伤后凋亡细胞数量在TBI 第1 d 明显增加,TBI后第7 d 神经细胞凋亡达到高峰.伤后注射黄体酮治疗组神经细胞凋亡指数明显下降(P ＜0.05).结论 大鼠TBI 后周围脑组织神经细胞凋亡在伤后持续增加,注射黄体酮能抑制细胞凋亡,对脑组织有一定保护作用.     

Automated monitoring of early neurobehavioral changes in mice following traumatic brain injury

Traumatic brain injury often causes a variety of behavioral and emotional impairments that can develop into chronic disorders. Therefore, there is a need to shift towards identifying early symptoms that can aid in the prediction of traumatic brain injury outcomes and behavioral endpoints in patients with traumatic brain injury after early interventions. In this study, we used the Smart Cage system, an automated quantitative approach to assess behavior alterations in mice during an early phase of traumatic brain injury in their home cages. Female C57BL/6 adult mice were subjected to moderate controlled cortical impact(CCI) injury. The mice then received a battery of behavioral assessments including neurological score, locomotor activity, sleep/wake states, and anxiety-like behaviors on days 1, 2, and 7 after CCI. Histological analysis was performed on day 7 after the last assessment. Spontaneous activities on days 1 and 2 after injury were significantly decreased in the CCI group. The average percentage of sleep time spent in both dark and light cycles were significantly higher in the CCI group than in the sham group. For anxiety-like behaviors, the time spent in a light compartment and the number of transitions between the dark/light compartments were all significantly reduced in the CCI group than in the sham group. In addition, the mice suffering from CCI exhibited a preference of staying in the dark compartment of a dark/light cage. The CCI mice showed reduced neurological score and histological abnormalities, which are well correlated to the automated behavioral assessments. Our findings demonstrate that the automated Smart Cage system provides sensitive and objective measures for early behavior changes in mice following traumatic brain injury.     

In vitro and in vivo effects of a novel dimeric inhibitor of PSD‐95 on excitotoxicity and functional recovery after experimental traumatic brain injury

PSD‐95 inhibitors have been shown to be neuroprotective in stroke, but have only to a very limited extent been evaluated in the treatment of traumatic brain injury (TBI) that has pathophysiological mechanisms in common with stroke. The aims of the current study were to assess the effects of a novel dimeric inhibitor of PSD‐95, UCCB01‐147, on histopathology and long‐term cognitive outcome after controlled cortical impact (CCI) in rats. As excitotoxic cell death is thought to be a prominent part of the pathophysiology of TBI, we also investigated the neuroprotective effects of UCCB01‐147 and related compounds on NMDA‐induced cell death in cultured cortical neurons. Anesthetized rats were given a CCI or sham injury, and were randomized to receive an injection of either UCCB01‐147 (10 mg/kg), the non‐competitive NMDAR‐receptor antagonist MK‐801 (1 mg/kg) or saline immediately after injury. At 2 and 4 weeks post‐trauma, spatial learning and memory were assessed in a water maze, and at 3 months, brains were removed for estimation of lesion volumes. Overall, neither treatment with UCCB01‐147 nor MK‐801 resulted in significant improvements of cognition and histopathology after CCI. Although MK‐801 provided robust neuroprotection against NMDA‐induced toxicity in cultured cortical neurons, UCCB01‐147 failed to reduce cell death and became neurotoxic at high doses. The data suggest potential differential effects of PSD‐95 inhibition in stroke and TBI that should be investigated further in future studies taking important experimental factors such as timing of treatment, dosage, and anesthesia into consideration.     

Aquaporin 4 expression and ultrastructure of the blood-brain barrier following cerebral contusion injury

This study aimed to investigate aquaporin 4 expression and the ultrastructure of the blood-brain barrier at 2–72 hours following cerebral contusion injury, and correlate these changes to the formation of brain edema. Results revealed that at 2 hours after cerebral contusion and laceration injury, aquaporin 4 expression significantly increased, brain water content and blood-brain barrier permeability increased, and the number of pinocytotic vesicles in cerebral microvascular endothelial cells increased. In addition, the mitochondrial accumulation was observed. As contusion and laceration injury became aggravated, aquaporin 4 expression continued to increase, brain water content and blood-brain barrier permeability gradually increased, brain capillary endothelial cells and astrocytes swelled, and capillary basement membrane injury gradually increased. The above changes were most apparent at 12 hours after injury, after which they gradually attenuated. Aquaporin 4 expression positively correlated with brain water content and the blood-brain barrier index. Our experimental findings indicate that increasing aquaporin 4 expression and blood-brain barrier permeability after cerebral contusion and laceration injury in humans is involved in the formation of brain edema.     

Selective death of newborn neurons in hippocampal dentate gyrus following moderate experimental traumatic brain injury

Memory impairment is one of the most significant residual deficits following traumatic brain injury (TBI) and is among the most frequent complaints heard from patients and their relatives. It has been reported that the hippocampus is particularly vulnerable to TBI, which results in hippocampus-dependent cognitive impairment. There are different regions in the hippocampus, and each region is composed of different cell types, which might respond differently to TBI. However, regional and cell type-specific neuronal death following TBI is not well described. Here, we examined the distribution of degenerating neurons in the hippocampus of the mouse brain following controlled cortical impact (CCI) and found that the majority of degenerating neurons observed were in the dentate gyrus after moderate (0.5 mm cortical deformation) CCI-TBI. In contrast, there were only a few degenerating neurons observed in the hilus, and we did not observe any degenerating neurons in the CA3 or CA1 regions. Among those degenerating cells in the dentate gyrus, about 80% of them were found in the inner granular neuron layer. Analysis with cell type-specific markers showed that most of the degenerating neurons in the inner granular neuron layer are newborn immature neurons. Further quantitative analysis shows that the number of newborn immature neurons in the dentate gyrus is dramatically decreased in the ipsilateral hemisphere compared with the contralateral side. Collectively, our data demonstrate the selective death of newborn immature neurons in the hippocampal dentate gyrus following moderate injury with CCI in mice. This selective vulnerability of newborn immature dentate neurons may contribute to the persistent impairment of learning and memory post-TBI and provide an innovative target for neuroprotective treatment strategies.     

Traumatic brain injury in the immature mouse brain: characterization of regional vulnerability

We characterized the regional and temporal patterns of neuronal injury and axonal degeneration after controlled cortical impact of moderate severity in mice at postnatal day 21. Animals were euthanized at 1, 3, or 7 days after injury or sham operation. The brains were removed and prepared for immunolocalization of neurons and microglia/macrophages or subjected to Fluoro-Jade and silver stains, indicators of irreversible neuronal cell injury and axonal degeneration. There was significant neuronal loss in both the ipsi- and the contralateral cortices, ipsilateral hippocampus, and ipsilateral thalamus by 7 days post injury compared to sham-operated animals. Activated microglia/macrophages were most prominent in regions of neuronal loss including the ipsilateral cortex, hippocampus, and thalamus. Neuronal injury, as evidenced by Fluoro-Jade labeling, was not apparent in sham-operated animals. In injured animals, labeling was identified in the ipsilateral cortex and hippocampus at 1 and 3 days post injury. Silver- and Fluoro-Jade-labeled degenerating axons were observed in the ipsilateral subcortical white matter by 1 day post injury, in the ipsilateral external capsule, caudate putamen, and contralateral subcortical white matter by 3 days post injury, and in the internal capsule, pyramidal tracts, and cerebellar peduncles by 7 days post injury. Our findings demonstrate that controlled cortical impact in the developing brain generates neuronal loss in both the ipsilateral and the contralateral cortex, a temporally distinct pattern of subcortical neuronal injury/death, and widespread white matter damage. These observations serve as an important baseline for studying human brain injury and optimizing therapies for the brain-injured child.     

Antisense knockdown of the glial glutamate transporter GLT-1 exacerbates hippocampal neuronal damage following traumatic injury to rat brain

Traumatic injury to rat brain induced by controlled cortical impact (CCI) results in chronic neuronal death in the hippocampus. In the normal brain, glutamate transporters actively clear the glutamate released synaptically to prevent receptor overactivation and excitotoxicity. Glutamate transporter 1 (GLT-1) is the most abundant and active glutamate transporter, which mediates the bulk of glutamate uptake. CCI injury significantly decreased GLT-1 mRNA (by 49-66%, P < 0.05) and protein (by 29-44%, P < 0.05) levels in the ipsilateral hippocampus, compared with either the respective contralateral hippocampus or the sham-operated control, 24-72 h after the injury. CCI injury in rats infused with GLT-1 antisense oligodeoxynucleotides (ODNs) exacerbated the hippocampal neuronal death and mortality, compared with the GLT-1 sense/random ODN-infused controls. At 7 days after the injury, hippocampal neuronal numbers were significantly lower in the CA1 (reduced by 32%, P < 0.05), CA2 (by 45%, P < 0.01), CA3 (by 68%, P < 0.01) and dentate gyrus (by 31%, P < 0.05) in GLT-1 antisense ODN-infused rats, compared with the GLT-1 sense/random ODN-infused controls. This study suggested a role for GLT-1 dysfunction in promoting the hippocampal neuronal death after traumatic brain injury.     

人脑挫裂伤早期周围组织AQP4表达及血脑屏障超微结构观察

目的观察人脑挫裂伤后AQP4和血脑屏障超微结构在脑水肿形成中不同时间点的变化特征,探讨脑水肿的形成机制。方法取脑挫裂伤区组织标本60例(观察组),10例非功能区正常脑组织标本(对照组)。采用免疫组化和图像分析技术测定正常组及观察组伤后2～72 h相应时间点水肿区AQP4的表达水平,同时观察脑水肿含水量,血脑屏障指数,血脑屏障超微结构的变化。结果与正常组相比较,脑挫裂伤组在伤后2 h后AQP4表达开始增加(P<0.05),6 h、8 h、12 h明显增加(P<0.01),24～72 h达到最高(P<0.01)。AQP4表达与脑含水量的变化趋于一致(r=0.912,P<0.01);血脑屏障(BBB)指数与脑含水量的变化趋于一致(r=0.877,P<0.01);水通道蛋白4表达与BBB指数呈显著正相关(r=0.908,P<0.01)。伤后早期血脑屏障结构即发生改变,随后血脑屏障结构被明显破坏,24 h、72 h血脑屏障破坏最为严重。结论脑挫裂伤后AQP4表达明显增强,BBB的通透性增加,提示AQP4在损伤后脑水肿的形成过程中起重要作用。