烟酰胺经调控p38MAPK信号通路对高血压脑出血大鼠的脑保护作用机制分析

摘要 目的：探讨烟酰胺经调控p38MAPK信号通路对高血压脑出血大鼠的脑保护作用机制。方法：选择48只SD大鼠,随机选择12只作为假手术组,其余36只进行高血压脑出血造模,对比4组大鼠的血肿体积、左扭转比率、神经功能变化、出血脑组织p-p38MAPK、p38MAPK蛋白表达、烟酰胺腺嘌呤二核苷酸、凋亡诱导因子含量及脑组织含水量。结果：与模型组相比,尼莫地平组、烟酰胺组的血肿体积明显缩小;与烟酰胺组相比,尼莫地平组的血肿体积明显缩小（P<0.05）;与干预前相比,干预后烟酰胺组、尼莫地平组的血肿体积明显缩小,模型组的血肿体积明显增多（P<0.05）。与模型组相比,假手术组、尼莫地平组、烟酰胺组的向左扭转比率、p-p38MAPK/p38MAPK、烟酰胺腺嘌呤二核苷酸明显较高,脑组织含水量、凋亡诱导因子含量明显较低;与烟酰胺组相比,尼莫地平组、假手术组的左扭转比率、p-p38MAPK/p38MAPK、烟酰胺腺嘌呤二核苷酸明显较高,脑组织含水量、凋亡诱导因子含量明显较低;与尼莫地平组相比,假手术组的左扭转比率、p-p38MAPK/p38MAPK、烟酰胺腺嘌呤二核苷酸明显较高,脑组织含水量、凋亡诱导因子含量明显较低（P<0.05）。结论：在高血压脑出血大鼠中,p38MAPK介导的细胞凋亡途径会加剧高血压脑出血的脑损伤,烟酰胺会经过抑制p38MAPK信号通路减轻高血压脑出血后的脑损伤。     

Modeling Intracerebral Hemorrhage in Mice: Injection of Autologous Blood or Bacterial Collagenase

Spontaneous intracerebral hemorrhage (ICH) defines a potentially life-threatening neurological malady that accounts for 10-15% of all stroke-related hospitalizations and for which no effective treatments are available to date^1,2. Because of the heterogeneity of ICH in humans, various preclinical models are needed to thoroughly explore prospective therapeutic strategies³. Experimental ICH is commonly induced in rodents by intraparenchymal injection of either autologous blood or bacterial collagenase⁴. The appropriate model is selected based on the pathophysiology of hemorrhage induction and injury progression. The blood injection model mimics a rapidly progressing hemorrhage. Alternatively, bacterial collagenase enzymatically disrupts the basal lamina of brain capillaries, causing an active bleed that generally evolves over several hours⁵. Resultant perihematomal edema and neurofunctional deficits can be quantified from both models. In this study, we described and evaluated a modified double injection model of autologous whole blood⁶ as well as an ICH injection model of bacterial collagenase⁷, both of which target the basal ganglia (corpus striatum) of male CD-1 mice. We assessed neurofunctional deficits and brain edema at 24 and 72 hr after ICH induction. Intrastriatal injection of autologous blood (30 μl) or bacterial collagenase (0.075U) caused reproducible neurofunctional deficits in mice and significantly increased brain edema at 24 and 72 hr after surgery (p<0.05). In conclusion, both models yield consistent hemorrhagic infarcts and represent basic methods for preclinical ICH research.     

Plasma leptin level predicts hematoma growth and early neurological deterioration after acute intracerebral hemorrhage

Higher plasma leptin levels have been associated with poor clinical outcomes after intracerebral hemorrhage. Nevertheless, their links with hematoma growth and early neurological deterioration are unknown. Therefore, we aimed to investigate the relationship between plasma leptin levels, hematoma growth, and early neurological deterioration in patients with acute intracerebral hemorrhage. We prospectively studied 102 consecutive patients with acute spontaneous basal ganglia hemorrhage presenting within 6 h from symptoms onset. Significant hematoma growth was defined as hematoma enlargement >33% at 24 h. Early neurological deterioration was defined as an increase of ≥4 points in National Institute of Health Stroke Scale score at 24 h from symptoms onset. We measured plasma leptin levels on admission using an enzyme-linked immunosorbent assay in a blinded fashion. In multivariate logistic regression analysis, plasma leptin level emerged as the independent predictor of hematoma growth (odds ratio, 1.182; 95% confidence interval, 1.061–2.598; P = 0.008) and early neurological deterioration (odds ratio, 1.193; 95% confidence interval, 1.075–2.873; P = 0.004). Using receiver operating characteristic curves, we calculated areas under the curve for hematoma growth (area under curve, 0.844; 95% confidence interval, 0.759–0.908) and early neurological deterioration (area under curve, 0.857; 95% confidence interval, 0.774–0.918). The predictive performance of leptin was similar to, but did not obviously improve that of hematoma volume. Thus, leptin may help in the prediction of hematoma growth and early neurological deterioration after intracerebral hemorrhage.     

Role of NADPH oxidase in the brain injury of intracerebral hemorrhage

The major risk factors for intracerebral hemorrhage (ICH) are hypertension and aging. A fundamental mechanism for hypertension- and aging-induced vascular injury is oxidative stress. We hypothesize that oxidative stress has a crucial role in ICH. To test our hypothesis, we used bacterial collagenase to produce ICH in wild-type C57BL/6 and gp91phox knockout (gp91phox KO) mice (deficient in gp91phox subunit of the superoxide-producing enzyme NADPH oxidase). All animals were studied at 20-35 weeks of age, resembling an older patient population. We found that collagenase produced less bleeding in gp91phox KO mice than wild-type mice. Total oxidative product was lower in gp91phox KO mice than in wild-type mice, both under basal conditions and after ICH. Consistent with the ICH volume, brain edema formation, neurological deficit and a high mortality rate was noted in wild-type but not in gp91phox KO mice. This ICH-induced brain injury in wild-type mice is associated with enhanced expression of the gp91phox subunit of NADPH oxidase. In conclusion, the oxidative stress resulting from activation of NADPH oxidase contributes to ICH induced by collagenase and promotes brain injury.     

应激性高血糖与急性自发性脑出血患者术后并发症和早期预后的相关性研究

目的:探讨应激性高血糖与自发性脑出血患者术后并发症及早期预后的关系。方法:回顾性分析我院收治的自发性脑出血患者358例,根据入院时血糖水平、糖化血红蛋白(HbAlc)及既往有无糖尿病史分为血糖正常组(96例)、应激性高血糖组(107例)及糖尿病组(155例),记录和比较各组入院时的血糖、格拉斯哥昏迷评分(GCS)、平均出血量及入院后30 d时各组的术后并发症发生情况、格拉斯哥预后评分(GOS)的差异。结果:糖尿病组入院时血糖水平、平均出血量、重型患者所占比率、脑出血破入脑室、颅内再出血、颅内感染、肺部感染、尿路感染及上消化道出血发生率、GOS分级植物状态或死亡发生率均明显高于应激性高血糖组(P0.05),GOS分级良好率低于应激性高血糖组(P0.05);而应激性高血糖组入院时血糖水平、平均出血量、重型患者所占比率、脑出血破入脑室、颅内再出血发生率、GOS分级植物状态或死亡发生率均明显高于血糖正常组(P0.05)。结论:自发性脑出血患者入院时应激性高血糖与患者的病情显著相关,可加重急性脑出血的不良预后。     

Attenuation of Acute Phase Injury in Rat Intracranial Hemorrhage by Cerebrolysin that Inhibits Brain Edema and Inflammatory Response

The outcome of intracerebral hemorrhage (ICH) is mainly determined by the volume of the hemorrhage core and the secondary brain damage to penumbral tissues due to brain swelling, microcirculation disturbance and inflammation. The present study aims to investigate the protective effects of cerebrolysin on brain edema and inhibition of the inflammation response surrounding the hematoma core in the acute stage after ICH. The ICH model was induced by administration of type VII bacterial collagenase into the stratum of adult rats, which were then randomly divided into three groups: ICH + saline; ICH + Cerebrolysin (5 ml/kg) and sham. Cerebrolysin or saline was administered intraperitoneally 1 h post surgery. Neurological scores, extent of brain edema content and Evans blue dye extravasation were recorded. The levels of pro-inflammatory factors (IL-1β, TNF-α and IL-6) were assayed by Real-time PCR and Elisa kits. Aquaporin-4 (AQP4) and tight junction proteins (TJPs; claudin-5, occludin and zonula occluden-1) expression were measured at multiple time points. The morphological and intercellular changes were characterized by Electron microscopy. It is found that cerebrolysin (5 ml/kg) improved the neurological behavior and reduced the ipsilateral brain water content and Evans blue dye extravasation. After cerebrolysin treated, the levels of pro-inflammatory factors and AQP4 in the peri-hematomal areas were markedly reduced and were accompanied with higher expression of TJPs. Electron microscopy showed the astrocytic swelling and concentrated chromatin in the ICH group and confirmed the cell junction changes. Thus, early cerebrolysin treatment ameliorates secondary injury after ICH and promotes behavioral performance during the acute phase by reducing brain edema, inflammatory response, and blood–brain barrier permeability.     

Tolerated nitrite therapy in experimental intracerebral hemorrhage: Rationale of nitrite therapy in a broad range of hyperacute strokes

Nitrite therapy is more effective in cerebral ischemia when administered earlier. It would be beneficial during the hyperacute stages of stroke if the nitrite effect is demonstrated in intracerebral hemorrhage (ICH). When nitrite is injected intravenously 3 h after ICH induction in rats, most doses of nitrite provided no beneficial effects on behavioral deficits, brain edema and hematoma volumes. A high dose of nitrite, however, decreased hematoma volume, but not brain edema. Peri-hematomal apoptosis and inflammation were similar between the control and nitrite groups. Nitrite therapy may be considered a therapeutic option in hyperacute stroke because nitrite therapy is tolerated in ICH as well.     

Effects of Atorvastatin on Pathological Changes in Brain Tissue and Plasma MMP-9 in Rats with Intracerebral Hemorrhage

To explore the effects of atorvastatin on hydrocephalus, neurocyte apoptosis, and the level of plasma matrix metalloproteinase-9 (MMP-9) after intracerebral hemorrhage (ICH) in rats. A rat model of ICH was established by intracerebral injection of collagenase. The brain water content was determined by the wet/dry weight ratio, ultrastructural changes in brain tissue were observed by electron microscopy, and the level of plasma MMP-9 was quantified by ELISA. Atorvastatin showed significant effects in reducing the brain water content, blocking neuron apoptosis, and decreasing plasma MMP-9 in rats with ICH. There was a positive linear correlation between plasma MMP-9 and the brain water content. Atorvastatin can significantly relieve brain edema, decrease the brain injury caused by MMP-9 and protect neurons in rats with ICH.     

Shogaol potentiates sevoflurane mediated neuroprotection against ischemia/reperfusion-induced brain injury via regulating apoptotic proteins and PI3K/Akt/mTOR/s6K signalling and HIF-1α/HO-1 expression

The current research was intended to evaluate the impact of 6-shogaol in rodent model of ischemic-reperfusion induced- brain injury and also assessed 6-shogaol enhanced sevoflurane's neuroprotective effects. Ischemic-Reperfusion (I/R) injury was induced by middle cerebral artery occlusion (MCAO) method in Sprague-Dawley rats. A separate group of animal was exposed to sevoflurane (2.5%) post-conditioning for 1 h immediately after reperfusion. The 6-shogaol (25 mg or 50 mg/kg body weight) was orally administered to treatment group rats for 14 days and then subjected to I/R. The 6-shogaol treatment along with/without sevoflurane post-conditioning reduced the number of apoptotic cell counts, brain edema and cerebral infarct volume. The western blotting analysis revealed a significant stimulation of the PI3K/Akt/mTOR signal pathway. RT-PCR and western blotting studies revealed improved expressions of HIF-1α and HO-1 at both gene level and protein levels. I/R induced neurological deficits were also alleviated on sevoflurane post-conditioning with/without 6-shogaol treatment. The present findings revealed that pre-treatment with 6-shogoal enhanced the neuroprotective properties of sevoflurane post-conditioning, illustrated the efficacy of the compound against I/R injury.     

局部亚低温联合血肿清除术治疗外伤性脑内血肿的临床疗效观察

目的:探讨局部亚低温联合血肿清除术治疗外伤性脑内血肿患者的临床疗效。方法:选择我院收治的外伤性脑内血肿患者89例,均给予血肿清除术治疗,其中47例接受血肿清除术联合局部亚低温治疗,评价和比较两组治疗后的临床疗效,术前及术后1天、1周、2周的美国国立卫生研究院卒中量表(NIHSS)评分和血肿体积。结果:治疗组有效率为93.6%,明显高于对照组(P0.05);治疗组术后1天、1周、2周的NIHSS评分明显高于对照组(P0.05),血肿大小明显小于对照组(P0.05)。结论:局部亚低温联合血肿清除术治疗外伤性脑内血肿能有效减轻患者脑部损害,提高患者神经功能。     

Puerarin attenuates intracerebral hemorrhage-induced early brain injury possibly by PI3K/Akt signal activation-mediated suppression of NF-κB pathway

Intracerebral hemorrhage (ICH) can induce intensively oxidative stress, neuroinflammation, and brain cell apoptosis. However, currently, there is no highly effective treatment available. Puerarin (PUE) possesses excellent neuroprotective effects by suppressing the NF-κB pathway and activating the PI3K/Akt signal, but its role and related mechanisms in ICH-induced early brain injury (EBI) remain unclear. In this study, we intended to observe the effects of PUE and molecular mechanisms on ICH-induced EBI. ICH was induced in rats by collagenase IV injection. PUE was intraperitoneally administrated alone or with simultaneously intracerebroventricular injection of LY294002 (a specific inhibitor of the PI3K/Akt signal). Neurological deficiency, histological impairment, brain edema, hematoma volume, blood–brain barrier destruction, and brain cell apoptosis were evaluated. Western blot, immunohistochemistry staining, reactive oxygen species (ROS) measurement, and enzyme-linked immunosorbent assay were performed. PUE administration at 50 mg/kg and 100 mg/kg could significantly reduce ICH-induced neurological deficits and EBI. Moreover, PUE could notably restrain ICH-induced upregulation of the NF-κB pathway, pro-inflammatory cytokines, ROS level, and apoptotic pathway and activate the PI3K/Akt signal. However, LY294002 delivery could efficaciously weaken these neuroprotective effects of PUE. Overall, PUE could attenuate ICH-induced behavioral defects and EBI possibly by PI3K/Akt signal stimulation-mediated inhibition of the NF-κB pathway, and this made PUE a potential candidate as a promising therapeutic option for ICH-induced EBI.     

Amount of Bleeding and Hematoma Size in the Collagenase-Induced Intracerebral Hemorrhage Rat Model

The aggravated risk on intracerebral hemorrhage (ICH) with drugs used for stroke patients should be estimated carefully. We therefore established sensitive quantification methods and provided a rat ICH model for detection of ICH deterioration. In ICH intrastriatally induced by 0.014-unit, 0.070-unit, and 0.350-unit collagenase, the amount of bleeding was measured using a hemoglobin assay developed in the present study and was compared with the morphologically determined hematoma volume. The blood amounts and hematoma volumes were significantly correlated, and the hematoma induced by 0.014-unit collagenase was adequate to detect ICH deterioration. In ICH induction using 0.014-unit collagenase, heparin enhanced the hematoma volume 3.4-fold over that seen in control ICH animals and the bleeding 7.6-fold. Data suggest that this sensitive hemoglobin assay is useful for ICH detection, and that a model with a small ICH induced with a low-dose collagenase should be used for evaluation of drugs that may affect ICH.     

Effects of Timing of Dexamethasone Treatment on the Outcome of Collagenase-Induced Intracerebral Hematoma in Rats

The effect of timing in providing dexamethasone treatment after intracerebral hematoma was evaluated in rats with hematoma induced by a subcortical collagenase injection. Male Sprague–Dawley rats (n = 30; body weight, 185 to 230 g) received dexamethasone (1 mg/kg) intraperitoneally at 2 h, 4 h, or 6 h (1 group per time point) after intracerebral collagenase injection, with another dose (1 mg/kg) administered at 24 h after collagenase injection. Neurologic examinations and rotarod treadmill tests were used to evaluate motor behavior before and at 24 and 48 h after intracerebral injection. Rats were euthanized after the last behavioral test. Brains were evaluated for hematoma size, number of penumbral necrotic neurons, neutrophils within the hematoma, and astrocytic response. Compared with the control and other treatment groups, rats treated with dexamethasone at 2 and 24 h after intracerebral collagenase injection scored significantly better on neurologic exams and rotarod tests. Hematoma volume was significantly smaller in all treated groups than in the control group but did not differ between treatment groups. Fewer neutrophils were seen in the perihematoma region of all treated rats compared with controls, but the number of necrotic neurons was decreased significantly only in the group treated with dexamethasone at 2 and 24 h. These results indicate that a 1-mg/kg dose of dexamethasone is beneficial for treatment of intracerebral hemorrhage, particularly if administered early after the hemorrhagic insult.Traumatic cerebral hemorrhages, which in veterinary patients are caused mainly by automobile accidents and falls, are diagnostic and therapeutic challenges.¹⁵ Animal models have played an important role in elucidating the cascade of cellular and biochemical events occurring after traumatic brain injury.⁷ These models have helped to elucidate various aspects of the pathogenesis and treatment of intracranial hemorrhaging. Among these, the collagenase-induced intracerebral hematoma model¹⁴ is highly reproducible and shows many characteristics of the intracerebral hemorrhagic process in mammals. In addition, the short- and long-term histologic and behavioral changes associated with this model have been evaluated.^5,6 Compared with the blood infusion model, the collagenase model causes greater primary injury that occurs distal to the hematoma, and neurologic deficits resolve less rapidly over time, making the collagenase model more appealing for long-term studies.¹²The efficacy of corticosteroids for the treatment of brain hemorrhages has been evaluated in different experimental studies with conflicting results.^3,8-11 Administration of corticosteroids at 1 h after hematoma induction is beneficial for the treatment of this condition.^10,11,16 Although these studies have promising results, the interval between trauma and treatment might greatly influence the response to corticosteroid treatment. The aim of this study was to assess the motor performance and histopathology associated with dexamethasone treatment at 2, 4, and 6 h after hematoma induction in the intracranial collagenase rat model. A second dexamethasone dose was administered 24 h after collagenase injection.     

Effect of Decompressive Craniectomy on Perihematomal Edema in Patients with Intracerebral Hemorrhage

Background

Perihematomal edema contributes to secondary brain injury in the course of intracerebral hemorrhage. The effect of decompressive surgery on perihematomal edema after intracerebral hemorrhage is unknown. This study analyzed the course of PHE in patients who were or were not treated with decompressive craniectomy.

Methods

More than 100 computed tomography images from our published cohort of 25 patients were evaluated retrospectively at two university hospitals in Switzerland. Computed tomography scans covered the time from admission until day 100. Eleven patients were treated by decompressive craniectomy and 14 were treated conservatively. Absolute edema and hematoma volumes were assessed using 3-dimensional volumetric measurements. Relative edema volumes were calculated based on maximal hematoma volume.

Results

Absolute perihematomal edema increased from 42.9 ml to 125.6 ml (192.8%) after 21 days in the decompressive craniectomy group, versus 50.4 ml to 67.2 ml (33.3%) in the control group (Δ at day 21 = 58.4 ml, p = 0.031). Peak edema developed on days 25 and 35 in patients with decompressive craniectomy and controls respectively, and it took about 60 days for the edema to decline to baseline in both groups. Eight patients (73%) in the decompressive craniectomy group and 6 patients (43%) in the control group had a good outcome (modified Rankin Scale score 0 to 4) at 6 months (P = 0.23).

Conclusions

Decompressive craniectomy is associated with a significant increase in perihematomal edema compared to patients who have been treated conservatively. Perihematomal edema itself lasts about 60 days if it is not treated, but decompressive craniectomy ameliorates the mass effect exerted by the intracerebral hemorrhage plus the perihematomal edema, as reflected by the reduced midline shift.     

组织扩张器辅助神经内镜治疗高血压脑出血的临床应用价值分析

目的:探讨组织扩张器辅助神经内镜治疗高血压脑出血的临床效果,为高血压脑出血的治疗提供依据。方法:选择我院2017年2月至2018年1月收治的高血压脑出血患者108例,其中应用组织扩张器辅助神经内镜治疗的高血压脑出血患者52例作为研究组,应用传统开颅血肿清除术治疗的高血压脑出血患者56例作为对照组。比较两组手术出血量、血肿清除率、手术时间、术后再出血率、术后并发症发生情况及术后3个月、术后6个月格拉斯哥预后评分(GOS)情况。结果:研究组手术时间短于对照组,研究组手术出血量、术后再出血率均低于对照组,血肿清除率高于对照组(P0.05)。研究组肺部感染、尿路感染发生率低于对照组(P0.05);两组消化道出血、深静脉血栓发生率比较差异无统计学意义(P0.05)。两组术后6个月GOS评分分布优于术后3个月,术后3个月、术后6个月研究组GOS评分分布优于对照组(P0.05)。结论:组织扩张器辅助神经内镜治疗高血压脑出血能有效缩短手术时间和减少术中出血量,其血肿清除率也更高,且患者术后并发症发生率较低,预后较好。     

尼莫地平治疗高血压性脑出血疗效观察

目的:尼莫地平治疗高血压性脑出血的临床疗效。方法:90例高血压脑出血患者随机分为实验组(45例)和对照组(45例),对照组仅采用常规治疗,实验组在常规治疗的基础上采用尼莫地平进行治疗,比较两组临床疗效、治疗前后的临床神经功能缺损评分、临床残疾评分以及血肿和水肿带体积改变。结果:实验组和对照组的治疗有效率为73.33%和42.22%,差异具有统计学意义(P<0.05)。实验组和对照组治疗前、后临床神经功能缺损评分分别为(18.58±3.06)、(12.31±2.74)和(18.28±2.97)、(15.22±2.72),实验组和对照组治疗前、后临床残疾评分分别为(38.93±3.37)、(61.57±3.03)和(37.51±4.962)和(43.48±7.19),实验组和对照组治疗前、后的血肿体积分别为(17.23±5.48)cm3、(7.93±3.33)cm3和(17.60±5.46)cm3、(10.97±4.25)cm3,实验组和对照组治疗前、后的水肿带体积分别为(7.73±3.20)cm3、(4.21±1.60)cm3和(7.83±3.19)cm3和(5.67±1.82)cm3,所有患者治疗后各指标均优于治疗前,治疗后两组组间比较均有有显著性(P<0.01)。结论:尼莫地平能够明显的减少血肿体积和水肿带的体积,提高治疗的效果,减少脑出血患者发生神经功能缺损和残疾的可能。     

Protection of Vascular Endothelial Growth Factor to Brain Edema Following Intracerebral Hemorrhage and Its Involved Mechanisms: Effect of Aquaporin-4

Vascular endothelial growth factor (VEGF) has protective effects on many neurological diseases. However, whether VEGF acts on brain edema following intracerebral hemorrhage (ICH) is largely unknown. Our previous study has shown aquaporin-4 (AQP4) plays an important role in brain edema elimination following ICH. Meanwhile, there is close relationship between VEGF and AQP4. In this study, we aimed to test effects of VEGF on brain edema following ICH and examine whether they were AQP4 dependent. Recombinant human VEGF165 (rhVEGF165) was injected intracerebroventricularly 1 d after ICH induced by microinjecting autologous whole blood into striatum. We detected perihemotomal AQP4 protein expression, then examined the effects of rhVEGF165 on perihemotomal brain edema at 1 d, 3 d, and 7 d after injection in wild type (AQP4^+/+) and AQP4 knock-out (AQP4^−/−) mice. Furthermore, we assessed the possible signal transduction pathways activated by VEGF to regulate AQP4 expression via astrocyte cultures. We found perihemotomal AQP4 protein expression was highly increased by rhVEGF165. RhVEGF165 alleviated perihemotomal brain edema in AQP4^+/+ mice at each time point, but had no effect on AQP4^−/− mice. Perihemotomal EB extravasation was increased by rhVEGF165 in AQP4^−/− mice, but not AQP4^+/+ mice. RhVEGF165 reduced neurological deficits and increased Nissl’s staining cells surrounding hemotoma in both types of mice and these effects were related to AQP4. RhVEGF165 up-regulated phospharylation of C-Jun amino-terminal kinase (p-JNK) and extracellular signal-regulated kinase (p-ERK) and AQP4 protein in cultured astrocytes. The latter was inhibited by JNK and ERK inhibitors. In conclusion, VEGF reduces neurological deficits, brain edema, and neuronal death surrounding hemotoma but has no influence on BBB permeability. These effects are closely related to AQP4 up-regulation, possibly through activating JNK and ERK pathways. The current study may present new insights to treatment of brain edema following ICH.     

Inhibition of Neuron-Specific CREB Dephosphorylation is Involved in Propofol and Ketamine-Induced Neuroprotection Against Cerebral Ischemic Injuries of Mice

Propofol and ketamine may provide certain degree of neuroprotection, but the underlying mechanism remains unclear to date. The cAMP response element-binding protein (CREB) was proposed that its phosphorylation at Ser133 (P-CREB) constituted a convergence point involved in neuroprotection. The purpose of this study was to determine whether different dosages of propofol and ketamine could provide neuroprotection against permanent middle cerebral artery occlusion (MCAO)-induced ischemic injuries and the involvement of P-CREB. Eighty adult male BALB/c mice that underwent 6 h MCAO were randomly divided into eight groups: Sham-operation; MCAO + saline; MCAO + 25, 50, 100 mg/kg propofol; and MCAO + 25, 50, 100 mg/kg ketamine (intraperitoneal injection 30 min following MCAO). We found that 50, 100 (not 25) mg/kg propofol, and 25 (not 50 and 100) mg/kg ketamine could significantly reduce the infarct volume, edema ratio and neurological deficit (n = 10 per group) as well as inhibit the decrease of P-CREB level in peri-infarct region when compared with that of MCAO + saline group (n = 6 per group). In addition, the results of double-labeled immunofluorescent staining showed that P-CREB co-localized with neuron-specific marker, NeuN, in the peri-infarct region of 50 mg/kg propofol and 25 mg/kg ketamine treated 6 h MCAO mice (n = 4 per group). These results suggested that inhibition of neuron-specific P-CREB dephosphorylation in the peri-infarct region is involved in high dose propofol and low dose ketamine-induced neuroprotection of 6 h MCAO mice.     

Tin-mesoporphyrin, a potent heme oxygenase inhibitor, for treatment of intracerebral hemorrhage: in vivo and in vitro studies.

Spontaneous intracerebral hemorrhage (ICH) is the stroke subtype with highest mortality and morbidity. ICH can also occur following traumatic brain injury and thrombolysis for ischemic stroke and myocardial infarction. Development of ICH-induced hemispheric edema can elevate intracranial pressure and cause death. In survivors, edema-related white matter injury can lead to life-long neurological deficits. At present, there are no scientifically proven treatments for ICH. Heme oxygenase products, particularly iron and bilirubin, can be toxic to cells. In cerebral ischemia models, metalloporphyrins that are potent heme oxygenase inhibitors, reduce edema and infarct size. Tin-mesoporphyrin (SnMP) is a neuroprotectant that has also been used clinically to treat hyperbilirubinemia. Presently, we tested the hypothesis that SnMP treatment would reduce edema development following experimental ICH. We produced hematomas in pentobarbital-anesthetized pigs (9-11 kg) by infusing autologous blood into the frontal white matter. To maximize tissue concentrations, SnMP (87.5 microM in DMSO) or DMSO (vehicle controls) was included in the infused blood. Pig brains were frozen in situ at 24 hrs. following ICH and hematoma and edema volumes were determined on coronal sections by computer-assisted image analysis. We also examined the effects of SnMP in vitro on ferritin iron release, the formation of iron-induced thiobarbituric acid reactive substances (TBARS) and initial clot formation and hemolysis. SnMP treatment significantly reduced intracerebral mass following ICH. This was due to significant decreases in hematoma (0.68+/-0.08 vs. 1.39+/-0.30 cc, vehicle controls p<0.025) and edema volumes (edema = 1. 16+/-0.33 vs. 1.77+/-0.31 cc, p<0.05). In vitro, SnMP did not stabilize ferritin iron against reductive release nor did it decrease iron-induced TBARS formation in brain homogenates. SnMP or DMSO added to pig blood did not alter clot weights. In conclusion, SnMP reduced intracerebral mass in an ICH model by decreasing both hematoma and edema volumes SnMP's mechanism of action is presently unknown but may involve its potent inhibition of heme oxygenase activity. SnMP's effect appears unrelated to ferritin iron release, antioxidant activity or initial clot formation. Since SnMP treatment could be brain protective following ICH, further investigations into neurological and neuropathological outcomes and as well as into its mechanism of action are warranted.