Acute inflammatory reaction following experimental intracerebral hemorrhage in rat

Previous studies on intracerebral hemorrhage (ICH) indicate that brain edema increases progressively in the first 24 h and remains elevated for several days. The cause of secondary brain injury and edema formation is uncertain. We hypothesized that inflammatory mediators released from the blood after cerebral hemorrhage might cause secondary brain injury and edema formation. This study investigates if, when and where inflammation occurs after ICH in rat. Immunocytochemistry for polymorphonuclear leukocyte marker (myeloperoxidase, MPO), microglia marker (OX42) and intracellular adhesion molecule-1 (ICAM-1) was performed in control, and 1, 3, 7 and 10 days after the injection of 100 microliter autologous blood in the right basal ganglia. Double labeling immunohistochemistry was used to identify ICAM-1 positive cells. The results show that an inflammatory response occurred in and around the blood clot after ICH, characterized by the infiltration of neutrophils and macrophages as well as activation of microglia. ICAM-1 immunoreactivity was observed in blood vessels adjacent to the clot, as well as in activated microglia and neurons in the ipsilateral hemisphere. The present study demonstrates there is an inflammatory response in the brain after ICH. Infiltrating leukocytes and activated microglia may release cytotoxic mediators contributing to secondary brain injury.     

补体在脑出血后脑组织损伤机制中的作用

目的研究补体C9在大鼠实验性脑出血(ICH)后血肿周围组织中的表达情况,探讨补体C9在ICH后脑水肿中的作用以及应用眼镜蛇毒因子(CVF)干预后对血肿周围组织C9表达及脑组织含水量变化的影响。方法采用立体定向技术,将自体不凝血注入大鼠尾状核制备ICH模型,将动物分为假手术组、出血组和CVF干预组,分别在不同时间断头取脑,连续切片分别作补体C9免疫组化染色和HE染色,并进行脑组织含水量测定(干湿重法)。结果ICH后2h血肿周围脑组织开始表达C9,24h达高峰。血肿周围脑组织含水量在ICH后2h开始增加(P<0.05),6h明显增加,24～72h达高峰(P<0.01),此后逐渐回落,1周基本恢复正常水平,脑组织含水量与C9的表达呈正相关关系(r=0.938,P<0.01);对侧半球相应部位及假手术对照组脑组织含水量没有明显变化;经CVF干预后,血肿周围组织C9表达明显下降,干预组与出血组之间比较有显著差异(P<0.01)。CVF干预组脑组织含水量明显低于常规ICH组(P<0.01)。结论脑出血后补体级联激活C9表达明显增加,并证明通过CVF干预后,C9表达下降,脑水肿减轻,能达到神经保护作用。     

大鼠脑出血后脑血流和脑水分含量变化的研究

研究大鼠脑出血后局部脑血流量（ｒＣＢＦ）与脑水分变化的规律及影响因素。用立体定向法自体血回注建立大鼠脑尾状核出血模型，分别在２４ｈ内不同时限用氢清除法测定ｒＣＢＦ，干湿重法测定脑水分含量，发现出血后１０ｍｉｎ同侧ｒＣＢＦ即下降，１ｈ达最低水平，出血量大时对侧半球也有明显下降；双侧脑水分含量均明显增加，其高峰期晚于ｒＣＢＦ的下降。说明脑出血后迅速出现广泛的低灌注和脑水肿     

大鼠脑出血后脑组织转铁蛋白表达的实验研究

目的　探讨大鼠自发性脑出血 (ICH)后不同时间脑组织中转铁蛋白 (Tf)的表达及其规律。方法　采用立体定向技术注入自体不凝血建立实验性大鼠ICH模型 ,在不同时间断头取脑 ,免疫组化染色检测脑组织中Tf阳性细胞的表达并与对照组比较。结果　ICH后 6h血肿周围及同侧大脑皮质Tf阳性细胞的表达增高 ,72h达高峰 ,然后下降 ,但第 7d时仍高于对照组 (P <0 0 5 )。结论　ICH后血肿周围和同侧大脑皮质Tf阳性细胞表达增高 ,推测Tf可能参与了ICH后神经元的保护并减轻迟发性脑水肿     

实验性脑出血血肿周围血流量变化的研究

目的　建立实验性脑出血的动物模型 ,探讨血肿周围的脑血流量变化。方法　采用犬脑内缓慢注入非肝素化自体血的方法建立实验性脑出血动物模型。用 1 4C- iodoantipyrine微示踪技术测定实验性脑出血 6 h、2 4 h、72 h血肿周围皮质、白质及对侧相应部位的脑血流量。结果　注血 6 h组、2 4 h组血肿周围白质的 CBF与对照组相比有所下降 ,但无统计学差异 ;而注血 72 h组血肿周围白质的 CBF较对照组降低了 19.8% (P<0 .0 5 ) ;注血 72 h组血肿对侧相应部位白质的 CBF较对照组升高了 14 .8% (P<0 .0 5 )。结论　犬脑内缓慢注入非肝素化自体血可建立可靠、重复性好的实验性 ICH动物模型 ,脑出血后 72 h,血肿周围白质的血流量下降 ,脑出血早期的脑损伤非缺血所致。     

Cyclooxygenase-2 modulates brain inflammation-related gene expression in central nervous system radiation injury

Although the contribution of cyclooxygenase-2 (COX-2) to peripheral inflammation is well documented, little is known about its role in brain inflammation. For this purpose we studied COX-2 expression in the mouse brain following ionizing radiation in vivo, as well as in murine glial cell cultures in vitro. The possible role of COX-2 in modulating brain inflammation was examined utilizing NS-398, a COX-2 selective inhibitor. Our results indicate that COX-2 is significantly induced in astrocyte and microglial cultures by radiation injury as well as in brain. Increased levels of prostaglandin E(2) in irradiated brain were reduced by NS-398. Moreover, NS-398 administration significantly attenuated levels of induction for the majority of inflammatory mediators examined, including TNFalpha, IL-1beta, IL-6, iNOS, ICAM-1, and MMP-9. In contrast, the chemokines MIP-2 and MCP-1 showed enhanced levels of induction following NS-398 administration. These results indicate that COX-2 modulates the inflammatory response in brain following radiation injury, and suggest the use of COX-2 selective inhibitors for the management of CNS inflammation.     

Oxidative brain injury from extravasated erythrocytes after intracerebral hemorrhage

Intracerebral infusion of lysed erythrocytes causes brain edema without inducing ischemic cerebral blood flow. Reports have indicated that oxidative damage contributes to secondary brain injury in stroke. In the present study, we investigated whether erythrocyte lysis after intracerebral hemorrhage (ICH) might result in oxidative brain damage. This study had four parts. Male Sprague-Dawley rats received an infusion of autologous lysed erythrocytes into the right striatum. Control rats only had a needle insertion. Neurological deficits, brain water and ion contents were determined in the first part. In the second part, hemoxygenase-1 (HO-1), manganese superoxide dismutase (Mn-SOD), copper/zinc SOD (CuZn-SOD) and protein carbonyl levels were determined by Western blot analysis. In the third part, immunohistochemistry was performed for HO-1. DNA damage was examined using DNA polymerase I-mediated biotin-dATP nick-translation (PANT) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) in the fourth part. Infusion of lysed RBCs induced marked edema in the ipsilateral striatum and profound neurological deficits. Western blot analysis and immunohistochemistry indicated that HO-1 was upregulated 24 h after infusion of lysed red blood cells. Both Mn-SOD and CuZn-SOD contents decreased, protein carbonyl levels increased in the ipsilateral striatum, and there was the appearance of PANT- and TUNEL-positive cells suggesting oxidative mechanisms in the erythrocyte-induced brain injury. In conclusion, oxidative stress caused by components of the lysed erythrocytes contributes to the brain injury after ICH.     

Celecoxib induces functional recovery after intracerebral hemorrhage with reduction of brain edema and perihematomal cell death.

The selective cyclooxygenase-2 (COX-2) inhibitor has been reported to have antiinflammatory, neuroprotective, and antioxidant effects in ischemia models. In this study, the authors examined whether a selective COX-2 inhibitor (celecoxib) reduces cerebral inflammation and edema after intracerebral hemorrhage (ICH), and whether functional recovery is sustained with longer treatment. ICH was induced using collagenase in adult rats. Celecoxib (10 or 20 mg/kg) was administered intraperitoneally 20 minutes, 6 hours, and 24 hours after ICH and then daily thereafter. Seventy-two hours after ICH induction, the rats were killed for histologic assessment and measurement of brain edema and prostaglandin E2. Behavioral tests were performed before and 1, 7, 14, 21, and 28 days after ICH. The brain water content of celecoxib-treated rats decreased both in lesioned and nonlesioned hemispheres in a dose-dependent manner. Compared with the ICH-only group, the number of TUNEL-positive, myeloperoxidase-positive, or OX42-positive cells was decreased in the periphery of hematoma and brain prostaglandin E2 level was reduced in the celecoxib-treated group. Celecoxib-treated rats recovered better by the behavioral tests at 7 days after ICH throughout the 28-day period, and the earlier the drug was administered, the better the functional recovery. Evidence of similar effects in an autologous blood-injected model showed that direct collagenase toxicity was not the major cause of inflammation or cell death. These data suggest that celecoxib treatment after ICH reduces prostaglandin E2 production, brain edema, inflammation, and perihematomal cell death in the perihematomal zone and induces better functional recovery.     

脑出血后脑水肿经时变化机制的探讨

目的 研究脑出血(mtracerebral hemorrhage，ICH)后血肿周围脑水肿与血脑屏障(blood-brain barrier，BBB)随时间变化的机制，从而为预防脑水肿提供依据。方法90只大耳白兔随机分为3组。1组：在立体定向仪下将300μl生理盐水注入兔左侧基底节；2组：注入200μl自身动脉血与100μl生理盐水；3组：注入200μl自身动脉血与100μl水蛭素。每组每时相(6h、12h、24h、48h、72h)各6只兔。脑组织含水量采用干湿重法测量，血脑屏障的通透性测定采用伊文思兰法。结果动脉血组及水蛭素干预组血肿周围脑组织含水量均在48h达到高峰．此后逐步降低。动脉血组伊文思兰(EB)于24h到达高峰，水蛭素干预组伊文思兰(EB)于48h达高峰。结论脑出血后脑水肿是多种因素综合作用的结果。早期可能和血块凝缩、流体静力压有关；至中期时凝血酶是主导因素；后期则主要由于红细胞裂解物的损害。     

Cerebroprotective action of a Na/Ca channel blocker NS-7: I. Effect on the cerebral infarction and edema at the acute stage of permanent middle cerebral artery occlusion in rats

The effect of a novel Na⁺/Ca²⁺ channel blocker NS-7 [4-(4-fluorophenyl)-2-methyl-6-(5-piperidinopentyloxy)pyrimidine hydrochloride] on the cerebral infarction, edema and brain energy metabolism was investigated in rats after permanent middle cerebral artery occlusion (MCAO). The infarction and brain water content were evaluated at 48 h and 24 h after MCAO, respectively. A single bolus injection of NS-7 (0.03125–0.25 mg/kg) immediately after MCAO produced a dose-dependent reduction in the infarct volume as well as edema both in the cerebral cortex and striatum. Glycerol (4 g/kg) also decreased water content both in the occluded and non-occluded brain, but it did not reduce the size of cerebral infarction. Unlike glycerol, NS-7 did not change the water content in non-occluded brain. Moreover, a significant protective action was still observed even when NS-7 was injected once at 12 h after occlusion. In addition, NS-7 significantly reversed the decrease in tissue ATP content observed at 3 h but not at 0.5 h after MCAO. These findings suggest that a Na⁺/Ca²⁺ channel blocker NS-7 protects cerebral tissues against ischemic insults by improving the disturbance of cerebral energy metabolism and suppressing the cerebral edema.     

微创清除血肿和重组水蛭素治疗脑出血后脑水肿的实验研究

目的探讨微创清除血肿和局部应用重组水蛭素对大鼠出血性脑水肿的治疗作用。方法成年雄性SD大鼠随机分为生理盐水组、脑出血组、微创组、水蛭素组、微创 水蛭素组,治疗时间点统一为出血后3h,以自体血注入大鼠尾状核方法建立脑出血模型,应用干-湿重法观察脑水肿变化,HE染色观察水肿细胞形态。每组每时相点(12h、24h、48h、72h、7d)6只大鼠。结果脑出血组和各治疗组脑含水量与生理盐水组在12h、24h、48h比,P<0.05;7d时各组间无明显差异(P>0.05);微创组与脑出血组组间比较,P>0.05;微创 水蛭素组与脑出血组组间比较,P<0.05。结论脑出血后早期(<3h)分别予以微创清除血肿、局部应用水蛭素及二者联合治疗可显著改善脑水肿,尤其微创与凝血酶抑制剂联合应用为脑出血治疗开辟新途径。     

脑出血后脑水含量变化及铁络合剂的作用

目的探讨脑出血后脑水肿的发生机制及铁络合剂的作用。方法将0．3ml自体血和0．3ml自体血 100mg去铁胺分别注入兔的两侧额叶,测定血肿周围脑组织的水含量。结果自体血注射后4h开始出现水肿,72h达高峰;去铁胺可减轻其水肿程度。结论红细胞在脑出血后脑水肿的形成中起重要作用;铁络合剂可减轻脑出血后脑水肿。     

Df—521巴曲酶对大鼠脑出血后脑水肿形成的影响

目的:观察Df-521巴曲酶对大鼠脑出血后脑水肿对血肿周边区脑组织ICAM-1表达的影响。方法:一侧基底节注射自体血制作大鼠脑出血模型,用干湿重法,测定脑组织含水量;用免疫组化法检测血肿周边水肿带ICAM-1的表达情况。结果:大鼠脑出血后,血肿侧脑组织含水量上升,同时水肿区ICAM-1的表达量增加;给予Df-521巴曲酶制剂处理后,血肿侧脑水肿减轻,脑组织ICAM-1的表达有所下降。结论:Df-521巴曲酶能下调脑出血后血肿周边组织ICAM-1的表达并减轻脑水肿的程度。     

NF-κB在大鼠实验性大脑内出血脑组织表达的研究

目的研究大鼠实验性大脑内出血后脑组织核转录因子κB(NF-κB)的表达及变化规律。方法采用立体定向技术将自体不凝血注入大鼠尾状核区制备不同时间段的大脑内出血模型,用免疫组化染色法检测不同出血时间脑组织NF-κB的表达。结果 NF-κB在神经元、神经胶质细胞及星形胶质细胞足突广泛表达。表达的阳性细胞数在出血后12 h上升,2 d达高峰,之后下降。结论 NF-κB可能参与了出血后脑水肿的形成。     

Cerebroprotective action of a Na+/Ca2+ channel blocker NS-7. I. Effect on the cerebral infarction and edema at the acute stage of permanent middle cerebral artery occlusion in rats

The effect of a novel Na+/Ca2+ channel blocker NS-7 [4-(4-fluorophenyl)-2-methyl-6-(5-piperidinopentyloxy)pyrimidine hydrochloride] on the cerebral infarction, edema and brain energy metabolism was investigated in rats after permanent middle cerebral artery occlusion (MCAO). The infarction and brain water content were evaluated at 48 h and 24 h after MCAO, respectively. A single bolus injection of NS-7 (0.03125-0.25 mg/kg) immediately after MCAO produced a dose-dependent reduction in the infarct volume as well as edema both in the cerebral cortex and striatum. Glycerol (4 g/kg) also decreased water content both in the occluded and non-occluded brain, but it did not reduce the size of cerebral infarction. Unlike glycerol, NS-7 did not change the water content in non-occluded brain. Moreover, a significant protective action was still observed even when NS-7 was injected once at 12 h after occlusion. In addition, NS-7 significantly reversed the decrease in tissue ATP content observed at 3 h but not at 0.5 h after MCAO. These findings suggest that a Na+/Ca2+ channel blocker NS-7 protects cerebral tissues against ischemic insults by improving the disturbance of cerebral energy metabolism and suppressing the cerebral edema.     

Efficacy of the lipid-soluble iron chelator 2,2'-dipyridyl against hemorrhagic brain injury

Previous studies have indicated that 2,2′-dipyridyl, a lipid-soluble ferrous iron chelator, can reduce brain injury after cerebral ischemia and reduce cerebral vasospasm after subarachnoid hemorrhage. In this study, we examined the efficacy of 2,2′-dipyridyl after intracerebral hemorrhage (ICH) in 12-month-old mice. ICH was modeled by intrastriatal injection of collagenase or autologous whole blood. 2,2′-Dipyridyl or vehicle was administered intraperitoneally 2 h before ICH (pretreatment) or 6 h after ICH (post-treatment) and then once daily for up to 3 days. Mice in the pretreatment group were sacrificed 1 or 3 days after ICH and examined for iron deposition, neuronal death, oxidative stress, microglial/astrocyte activation, neutrophil infiltration, and white matter damage. Mice in the post-treatment group were examined for brain lesion volume and edema on day 3 and for neurologic deficits on days 1, 3, and 28 after ICH. Pretreatment with 2,2′-dipyridyl decreased iron accumulation and neuronal death, attenuated production of reactive oxygen species, reduced microglial activation without affecting astrocytes or neutrophil infiltration, and attenuated white matter damage. Post-treatment reduced brain lesion volume and edema and improved neurologic function. These results indicate that the lipid-soluble ferrous iron chelator 2,2′-dipyridyl can reduce brain injury and improve functional outcome after ICH.     

Minocycline protects the blood-brain barrier and reduces edema following intracerebral hemorrhage in the rat

Intracerebral hemorrhage (ICH) results from rupture of a blood vessel in the brain. After ICH, the blood–brain barrier (BBB) surrounding the hematoma is disrupted, leading to cerebral edema. In both animals and humans, edema coincides with inflammation, which is characterized by production of pro-inflammatory cytokines, activation of resident brain microglia and migration of peripheral immune cells into the brain. Accordingly, inflammation is an attractive target for reducing edema following ICH. In the present study, BBB damage was assessed by quantifying intact microvessels surrounding the hematoma, monitoring extravasation of IgG and measuring brain water content 3 days after ICH induced by collagenase injection into the rat striatum. In the injured brain, the water content increased in both ipsilateral and contralateral hemispheres compared with the normal brain. Quantitative real-time RT-PCR revealed an up-regulation of inflammatory genes associated with BBB damage; IL1β, TNFα and most notably, MMP-12. Immunostaining showed MMP-12 in damaged microvessels and their subsequent loss from tissue surrounding the hematoma. MMP-12 was also observed for the first time in neurons. Dual-antibody labeling demonstrated that neutrophils were the predominant source of TNFα protein. Intraperitoneal injection of the tetracycline derivative, minocycline, beginning 6 h after ICH ameliorated the damage by reducing microvessel loss, extravasation of plasma proteins and edema; decreasing TNFα and MMP-12 expression; and reducing the numbers of TNFα-positive cells and neutrophils in the brain. Thus, minocycline, administered at a clinically relevant time, appears to target the inflammatory processes involved in edema development after ICH.     

大鼠实验性脑出血后脑组织中c-fos基因的表达与局部脑血流的改变

目的 探讨大鼠实验性脑出血后脑组织中即刻早期基因c-fos的表达和局部脑血流的变化。方法 采用Nath改良法建立大鼠脑出血模型；免疫组化法及RT－PCR法测定其脑组织中fos蛋白和c-fos mRNA的表达；氢清除法测定其局部脑血流。结果 大鼠血肿周围区（基底节）在脑出血后1小时即出现fos蛋白的表达，至3小时达高峰；c-fos mRNA于出血后1小时达表达高峰,至3小时后仍有较高水平的表达；出血后1小时全脑的的血流量均下降，4小时恢复至对照组水平，并维持至出血后24小时，随着的24小时内再次出现脑血流下降。结论 大鼠脑出血后，血肿周围区和双侧皮质区的脑组织中存在着c-fos基因的快速而长久的诱导表达。局部脑血流的下降相对短暂，且脑血流的下降在时程上与c-fos基因的表达不相一致。     

Acute gastric changes after intracerebral hemorrhage in rats

Severe intracerebral hemorrhage (ICH) produces gastric pathology in about 30% of the patient population, even after the standard treatment of H2 receptor blockers or proton pump inhibitors. This study was undertaken to establish a rat model of ICH-induced gastric ulcer. Adult male Sprague-Dawley rats (300-350 g) were divided into two hemorrhage groups and a sham control group. ICH was produced either by injection of 100 microl of autologous arterial blood or by injection of 4 microl saline containing 0.6 unit of bacterial collagenase VII into the right basal ganglia. Rats were sacrificed at 24, 48, 72 h, and 7 days after ICH to harvest brains and stomachs. Greater degrees of hemorrhage and brain edema were observed in collagenase-induced ICH. Motor behavior decreased significantly after 24 h in both models. The incidence of acute ulceration with destruction of the forestomach epithelium was extremely low at 8.7% in the collagenase injection model and 4.8% in the blood injection rats. Small, pinpoint hemorrhages (petechiae) were noticed in 38% of rats after blood injection and 22% after collagenase injection, in the glandular portion of the gastric mucosa with penetration of red blood cells and inflammatory cells into the gastric mucosa. Enhanced tumor necrosis factor alpha (TNFalpha) and cyclooxygenase 2 (COX-2) expressions were observed in gastric tissues after ICH with more intense staining occurring at 24 and 48 h. Due to the low incidence of ulceration, ICH-induced gastric ulceration in rodents may not appropriate for evaluating the potential human risk of gastric ulceration after ICH.     

Cyclooxygenase-2 selective inhibitors aggravate kainic acid induced seizure and neuronal cell death in the hippocampus.

Cyclooxygenase-2 (COX-2) in the brain is expressed constitutively and also increased in pathological conditions such as seizure, cerebral ischemia, and inflammation. This study examined the role of COX-2 in kainic acid-induced seizure and in the following neuronal death by using selective inhibitors. Systemic kainate injection (50 mg/kg; i.p.) in mice evoked seizure within 15 min and led to 29% mortality within 2 h. TUNEL-positive neuronal death peaked at 3 days after injection and was prominent in CA(3a) regions of the hippocampus. NS-398 or celecoxib (10 mg/kg, COX-2 selective inhibitor) and indomethacin (5 mg/kg, nonselective inhibitor) exaggerated kainic acid-induced seizure activity and mortality. COX-2 selective inhibitors induced the seizure at earlier onset and more severe mortality within the first hour than indomethacin and aspirin. NS-398 also aggravated kainic acid-induced TUNEL positive neuronal death and decreased Cresyl violet stained viable neurons, and extended lesions to CA(1) and CA(3b). Kainic acid increased the levels of PGD(2), PGF(2a) and PG E(2) in the hippocampus immediately after injection. Indomethacin attenuated the production of basal and kainic acid-induced prostaglandins. In contrast, NS-398 failed to reduce until the first 30 min after kainic acid injection, during which the animals were severely seizured. It has been challenged the endogenous PGs might have anticonvulsant properties. Thus, COX-2 selective inhibitor, including nonselective inhibitor such as indomethacin, aggravated kainic acid-induced seizure activity and the following hippocampal neuronal death even with variable prostaglandin levels.