Temporal profile of tissue plasminogen activator (tPA) and inhibitor expression after transient focal cerebral ischemia

Altered tPA expression may influence the fate of neurons after cerebral ischemia. We determined the changes in tPA and plasminogen activator inhibitor (PAI-1) expression in adult rat brain after transient middle cerebral artery (MCA) occlusion. Immunohistology revealed tPA staining in ipsilateral but not contralateral cortex and striatum 6 h after occlusion. This pattern was maintained at 24 h. Staining data was supported by Western blot data which showed no tPA protein in contralateral cortex at 3 h but abundant protein in ipsilateral cortex which increased further at 6 h and 24 h. In contrast there was prominent PAI-1 immunostaining and protein expression in control tissue after MCA occlusion but it diminished progressively at 3, 6 and 24 h in the lesioned cortex.     

大鼠急性脑缺血后Hephaestin的表达变化

目的 研究大鼠急性局灶性脑缺血后皮质和纹状体Hephaestin表达的变化。方法 线栓法制备大鼠急性大脑中动脉阻塞(MCAO)再灌注模型,在再灌注后的不同时间点应用免疫组化、图像分析以及SDS-PAGE Werstern blot方法检测缺血侧皮质和纹状体的表达变化。结果 MCAO再灌注后大鼠出现大脑中动脉梗死的神经系统损害体征,TTC染色有白色梗死区。Hephaestin在正常大鼠的皮质、纹状体有表达,在急性脑缺血再灌注后12h缺血侧皮质、纹状体表达明显增加并持续到再灌注后48h,在24h时到达高峰(P<0.01),至1周时表达较正常明显减少(P<0.01)。结论 大鼠急性脑缺血再灌注后Hephaestin的表达出现明显的变化,在急性脑缺血的病理生理变化中可能起着重要的作用。     

Acidosis causes endoplasmic reticulum stress and caspase-12-mediated astrocyte death.

Endoplasmic reticulum (ER) stress leads to activation of caspase-12, which in turn can lead to activation of caspase-3 and cell death. Here we report that transient acidosis induces ER stress and caspase-12-mediated cell death in mouse astrocytes. After a 3-hour incubation at pH 6.0, astrocytes exhibited delayed cell death associated with nuclear condensation and fragmentation. Cell death was reduced by the protein synthesis inhibitor cycloheximide, further suggesting an active cell death program. Acidosis increased the expression of the ER chaperone protein GRP-78, indicative of ER stress. Acidosis also increased caspase-12 mRNA expression, caspase-12 protein expression, cleavage of caspase-12 to its active form, and activation of caspase-3. Each of these effects was suppressed in astrocytes pretreated with caspase-12 antisense phosphorodiamidate morpholino oligodeoxynucleotides (PMOs). Caspase-12 antisense PMOs also reduced the cell death induced by acidosis. Immunoprecipitation studies showed dissociation of both caspase-12 and Ire1-alpha from GRP-78, thereby suggesting a mechanism by which acidosis can initiate the ER stress response. To evaluate caspase-12 activation in vivo, rats were subjected to middle cerebral artery ischemia-reperfusion. Immunostaining of brain sections harvested 24 hours later showed increased caspase-12 expression and nuclear condensation in astrocytes of the periinfarct region exposed to acidosis during ischemia. These findings suggest that acidosis induces ER stress and caspase-12 activation, and that these changes may contribute to delayed cell death after ischemia.     

大鼠脑缺血时凋亡相关基因bc1-2和bax的分布特点

目的 研究大鼠脑缺血时ｂｃｌ－２和ｂａｘ在神经元凋亡中的作用。方法 阻塞大脑中动脉２ｈ再灌流０．５～４８ｈ制成脑缺血模型,免疫组化法观察ｂｃｌ－２和ｂａｘ的分布。结果 正常组、皮质神经元的胞膜和突起ｂｃｌ－２阳性,纤维束外强了性。０．５～３ｈ,ｂｃｌ－２强表达于缺血区皮质和纹状体的纤维,呈丝网状;６～１２ｈ,丝网状的阳性纤维呈树枝状;２４～４８ｈ,纹状体丝网状纤维和皮质树枝状的突起尤为突出。正常组,ｂａｘ强表达于一些核团如视交叉上核、背内侧核等;０．５～３ｈ,缺血中心区皮质和纹状体ｂａｘ阴性,周边区有少量中等阳性的细胞;２４～４８ｈ,缺血区皮质、尾壳核有少量散在的中等阳性神经元。结论 ｂｃｌ－２和ｂａｘ分别强表达于缺血区和缺血周边区的神经元,在神经元的存活或死亡中起作用。     

细胞外信号调节激酶在NGF/VEGF介导的神经保护作用中的动态变化及其调控机制

目的探讨细胞外信号调节激酶1(ERK1)在局灶性脑缺血/再灌注不同时间、不同脑区的动态时空变化,以及其在NGF/VEGF介导的神经保护作用中的调控表达机制。方法采用兔大脑中动脉阻断(MCAO)局灶性脑缺血再灌注模型,所有动物随机分为假手术组(n=6)、缺血/再灌注组(n=60)、因子干预组(n=40)。应用免疫组化检测ERK1在脑缺血/再灌注损伤不同脑区的动态表达,同时,应用免疫组化、流式细胞术和电镜检测caspase-3表达、凋亡和超微结构的变化。结果免疫组化分析显示,再灌注损伤1hERK1首先在海马CA3和齿状回(DG)表达增加,6h后其它脑区也相继增加,随再灌注时间延长而加剧,1~3d达高峰。再灌注1hcaspase-3活性表达在各脑区迅速增加,3d达高峰。应用神经保护剂(NGF/VEGF)后各脑区ERK1表达呈明显抑制,caspase-3表达同时被抑制。结论ERK信号通路可能通过调节死亡受体途径介导神经保护作用,抑制ERK信号途径可能是减轻脑缺血损伤过程中神经细胞死亡的有效方法。     

Time Course Study of GFRα-1 Expression in an Animal Model of Stroke

Previous studies have shown that intracerebral administration of glial cell line-derived neurotrophic factor (GDNF) reduces ischemia-mediated cerebral infarction. The biological effects of GDNF are mediated by GDNF-family receptor α-1 (GFRα-1) and c-Ret. In this study, we examined the levels of expression of GFRα-1 and c-Ret in a rat model of stroke. Adult Sprague–Dawley rats were anesthetized with chloral hydrate. The right middle cerebral artery was ligated at its distal branch for 90 min. Animals were sacrificed at 0, 6, 12, and 24 h after reperfusion and levels of expression of GFRα-1 and c-Ret mRNA were determined by in situ hybridization histochemistry. We found that GFRα-1 mRNA was up-regulated in CA3, dentate gyrus (DG), cortex, and striatum. The peak of up-regulation in DG was 6 h after reperfusion. GFRα-1 mRNA levels in CA3 were gradually up-regulated over the 24-h reperfusion period. In cortex, GFRα-1 mRNA was up-regulated at all time points; however, the peak of up-regulation was observed at 0 and 24 h after reperfusion. In striatum, an initial up-regulation of GFRα-1 was found at 0 h after ischemia. In striatum, up-regulation of c-Ret mRNA was detected as early as 0 h after reperfusion. A gradual increase was found at 6, 12, and 24 h after reperfusion. In conclusion, our results indicate that there are both regional and temporal differences in up-regulation of GFRα-1 and c-Ret after ischemia. Since GDNF is neuroprotective, up-regulation of GFRα-1 and c-Ret could enhance the responsiveness to GDNF and reduce neuronal damage. The selective up-regulation of GFRα-1 and c-Ret in different brain areas suggests that there may be regional differences in GDNF-induced neuroprotection in stroke.     

Inhibition of Na(+)-K(+)-Cl(-) cotransporter during focal cerebral ischemia decreases edema and neuronal damage

Our previous study demonstrated that pharmacological inhibition of the Na(+)-K(+)-Cl(-) cotransporter isoform 1 (NKCC1) during ischemia and reperfusion attenuated neuronal damage and edema. In this study, we further investigated whether NKCC1 activity contributes to ischemic damage during either ischemia or reperfusion. Immunoblotting revealed that expression of NKCC1 protein was increased following 2-h focal ischemia in cerebral cortex. A sustained up-regulation of NKCC1 in cortex was detected at 4, 8, 12, and 24 h of reperfusion. An increase in the phosphorylated NKCC1 (NKCC1-p) was found at 4 and 8 h of reperfusion. In striatum, a significant increase in NKCC1 expression occurred between 4 and 24 h of reperfusion and no elevation of NKCC1-p signal was observed. Artificial cerebral spinal fluid (aCSF) or 100 microM bumetanide in aCSF were continuously microdialyzed into left cortices either 1 h prior to ischemia plus 2-h ischemia, or only during 24-h reperfusion. Infarction volume was significantly decreased in the pre-ischemic bumetanide-treated group (P<0.05) but not in the post-ischemic treatment group (P>0.05). In addition, pre-ischemic bumetanide treatment reduced the ipsilateral water content increase by 70% (P<0.05). Inhibition of NKCC1 did not attenuate poly (ADP-ribose) polymerase cleavage or the number of TUNEL-labeled apoptotic cells in ischemic brains. These results suggest that inhibition of NKCC1 attenuates cytotoxic edema and necrotic neuronal death during focal ischemia. Activation of NKCC1 activity plays a role in the early stage of ischemic damage.     

Prolonged bihemispheric alterations in unfolded protein response related gene expression after experimental stroke

After ischemia, endoplasmic reticulum (ER) stress pathways are activated that include unfolded protein response (UPR) and protein synthesis inhibition (PSI). Both of these mechanisms aim to restore ER functioning mainly by inhibition of translation and increased processing of excess proteins in ER. We were interested in the role of these pathways during spontaneous recovery after transient middle cerebral artery occlusion (MCAO) in rats. The spontaneous recovery of rats was assessed with a limb-placing test. The expression of ER-stress-related genes (IRE1, ATF6, GRP78, eif2alpha, ATF4, PERK) was studied by using in situ hybridization in different brain areas on post-operative days 2, 7, 14 and 28. Elevated signals were detected in striatum contralateral to the lesion on days 2 (PERK and IRE1) and 14 post-ischemia (IRE1). Gene expression was elevated on day 7 in the striatum ipsilateral to the lesion (ATF6 and GRP78) and on day 14 (GRP78) post-ischemia. Furthermore, elevated levels of GRP78 were detected on day 14 after ischemia in the ipsilateral sensorimotor cortex. These results suggest that altered gene expression related to unfolded protein response may be more long lasting than expected following focal cerebral ischemia. In addition, these results show that the response to ER stress differs ipsi- and contralaterally after MCAO in rats. Since these differences are detected in both hemispheres only in areas adjacent to the lesion, UPR may contribute to spontaneous recovery after MCAO in rats.     

大鼠局灶性脑缺血后再灌注期caspase—9 mRNA及Apaf—1mRNA表达的动态变化

目的探讨大鼠局灶性脑缺血后再灌注期caspase-9 mRNA及Apaf-1 mRNA表达的动态变化.方法采用线栓法制作大鼠局灶性脑缺血后再灌注模型,以逆转录聚合酶链式反应(RT-PCR)技术检测caspase-9 mRNA及Apf-1 mRNA的表达.结果缺血2 h后再灌注,缺血皮质中caspase-9 mRNA的表达在再灌注后24h达高峰,48h仍保持高水平,而Apaf-1 muRNA的表达无明显改变.结论局灶性脑缺血后再灌注48h内caspase-9 mRNA表达增强.     

Necrosis, apoptosis and hybrid death in the cortex and thalamus after barrel cortex ischemia in rats

Focal ischemia in the cerebral cortex results in acute and delayed cell death in the ischemic cortex and non-ischemic thalamus. We examined the hypothesis that neurons in ischemic and non-ischemic regions died from different mechanisms; specifically, we tested whether a mixed form of cell death containing both necrotic and apoptotic changes could be identified in individual cells.Focal barrel cortex ischemia in rats was induced by occlusion of small branches of the middle cerebral artery (MCA) corresponding to the barrel cortex, local blood flow was measured by quantitative autoradiography. Cell death was visualized by 2,3,5-triphenyltetrazolium chloride (TTC) staining, hematoxylin-eosin (H&E) staining, the terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and caspase-3 staining 1 to 10 days after the ischemia. Electron microscopy was used for ultrastructural examination. Cell death occurred in the ipsilateral cortex 24 h after ischemia, followed by selective neuronal death in the ventrobasal (VB) thalamus 3 days later. TUNEL positive neurons were found in these two regions, but with striking morphological differences, designated as type I and type II TUNEL positive cells. The type I TUNEL positive cells in the ischemic cortex underwent necrotic changes. The type II TUNEL positive cells in the thalamus and the cortex penumbra region represented a hybrid death, featured by concurrent apoptotic and necrotic alterations in individual cells, including marked caspase-3 activation, nuclear condensation/fragmentation, but with swollen cytoplasm, damaged organelles and deteriorated membranes. Cell death in the thalamus and the cortex penumbra were attenuated by delayed administration of the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp fluoromethylketone (Z-VAD-FMK). Our data suggest that TUNEL staining should be evaluated with morphological changes, the hybrid death but not typical apoptosis occurs in the penumbra region and non-ischemic thalamus after cerebral ischemia.     

The role of Rho/Rho-kinase pathway and the neuroprotective effects of fasudil in chronic cerebral ischemia

The Rho/Rho-kinase signaling pathway plays an important role in cerebral ischemia/reperfusion injury. However, very few studies have examined in detail the changes in the Rho/Rho-kinase signaling pathway in chronic cerebral ischemia. In this study, rat models of chronic cerebral ischemia were established by permanent bilateral common carotid artery occlusion and intragastrically administered 9 mg/kg fasudil, a powerful ROCK inhibitor, for 9 weeks. Morris water maze results showed that cognitive impairment progressively worsened as the cerebral ischemia proceeded. Immunohistochemistry, semi-quantitative RT-PCR and western blot analysis showed that the expression levels of Rho-kinase, its substrate myosin-binding subunit, and its related protein alpha smooth muscle actin, significantly increased after chronic cerebral ischemia. TUNEL staining showed that chronic cerebral ischemia could lead to an increase in neuronal apoptosis, as well as the expression level of caspase-3 in the frontal cortex of rats subjected to chronic cerebral ischemia. Fasudil treatment alleviated the cognitive impairment in rats with chronic cerebral ischemia, and decreased the expression level of Rho-kinase, myosin-binding subunit and alpha smooth muscle actin. Furthermore, fasudil could regulate cerebral injury by reducing cell apoptosis and decreasing caspase-3 expression in the frontal cortex. These findings demonstrate that fasudil can protect against cognitive impairment induced by chronic cerebral ischemia via the Rho/Rho-kinase signaling pathway and anti-apoptosis mechanism.     

局灶性脑缺血再灌注损伤核心区及半暗带的组织学定位

目的观察局灶性脑缺血1h和2h,再灌注至24h后的组织损伤及核心区和半暗带的组织学定位。方法利用大鼠局灶脑缺血模型及HE染色和图像分析,对损伤进行定量。结果缺血核心区表现为脑组织的完全坏死,半暗带位于核心区周围,表现为选择性神经元死亡,其中缺血1h组的病变变异较大。缺血2h组的皮质、纹体和半球核心区及其半球病变明显大于缺血1h组(P依次<0.02、0.01、0.01和0.05)。依据大鼠脑立体定位图谱,对缺血2h和缺血1h的皮质、纹体核心区和半暗带进行了组织学定位。结论脑缺血损伤时,皮质和纹体均存在核心区和半暗带,其定位相对恒定,为应用脑微透析方法探讨脑缺血损伤机制,提供了组织学依据。     

石杉碱甲、尼莫地平对脑缺血鼠学习记忆障碍与血管内皮生长因子、Caspase-3表达的影响

目的:对脑缺血大鼠采用尼莫地平与石杉碱甲进行药物干预治疗,观察治疗后不同药物组血管内皮生长因子(VEGF)、caspase-3表达水平与学习记忆改善程度。方法:采用免疫组化和Y迷宫检测脑缺血鼠学习记忆功能的变化及VEGF、caspase-3在缺血区的表达。结果:各治疗组VEGF、caspase-3在海马区、大脑皮质、基底节区表达均显著低于脑缺血对照组(A组)P<0.01,尤以海马、大脑皮质区较显著。其中石杉碱甲加尼莫地平干预组(B组)VEGF、caspase-3细胞阳性表达的降低和学习记忆功能的改善,明显好于A、C、D组,P<0.01。结论:石杉碱甲加尼莫地平治疗组与其他药物治疗组比,能有效改善VEGF、caspase-3表达水平和提高学习记忆的能力,为认知障碍早期的治疗提供依据。     

Calpain inhibitor MDL 28170 protects hypoxic-ischemic brain injury in neonatal rats by inhibition of both apoptosis and necrosis

MDL 28170 is a CNS-penetrating calpain inhibitor, and we examined the effects of MDL 28170 on hypoxic-ischemic brain injury in immature brain using the Rice-Vannucci model. Immediately after hypoxic exposure, 24 mg/kg of MDL 28170 was injected intraperitoneally as an initial dose, followed by 12 mg/kg every 4 h for a total dose of 60 mg/kg over 12 h post-HI. A vehicle control group received peanut oil injection instead. Macroscopic evaluation of brain injury revealed the neuroprotective effect of MDL 28170 after 12 h post-HI. Neuropathological quantitative analysis of cell death showed that MDL 28170 significantly decreased the number of necrotic cells in all the examined regions except for cingular cortex, and the number of apoptotic cells in caudate putamen, parietal cortex, hippocampus CA1, and laterodorsal thalamus. Western blots showed that MDL 28170 suppressed 145/150 kDa subunits of alpha-spectrin breakdown products (SBDP) in cortex, hippocampus, thalamus, and striatum, and also 120-kDa subunit of SBDP in all regions except for striatum. This suggests that MDL 28170 inhibited activation of calpain and caspase-3, respectively. Our results indicate that post-hypoxic MDL 28170 injection is neuroprotective in HI newborn rat brain by decreasing both necrosis and apoptosis. SBDP expression also suggests that MDL 28170 injection inhibits both calpain and caspase-3 activation after HI insult.     

亚低温通过抑制两种凋亡通路对大鼠脑缺血再灌注损伤发挥保护作用

目的探讨亚低温对大鼠局灶性脑缺血再灌注后胱冬酶(caspase)依赖性及非依赖性两种凋亡通路的影响。方法线栓法建立大鼠大脑中动脉阻塞(M CAO)及再通模型,分为假手术组、常温及亚低温脑缺血再灌注组,应用RT-PCR技术检测再灌注后不同时相缺血侧皮层凋亡诱导因子(A IF)及caspase-3 mRNA的表达。结果脑缺血2h再灌注2~4h,A IF及caspase-3 mRNA表达开始增加,随着再灌注时间的延长表达逐渐增强,至再灌注24h达高峰。每一再灌注时间点亚低温组与常温组A IF及caspase-3 mRNA表达均有显著差异,亚低温组mRNA表达均低于相应常温组。结论亚低温不仅降低caspase依赖性通路中的关键蛋白酶—caspase-3的mRNA的表达,而且降低caspase非依赖性通路中的关键蛋白—A IF的mRNA的表达,亚低温通过抑制两种凋亡通路对大鼠脑缺血再灌注损伤发挥保护作用。     

Involvement of oxidative stress and caspase-3 in cortical infarction after photothrombotic ischemia in mice.

Apoptosis-related cell death is linked to oxidative stress and caspases in experimental cerebral ischemia. However, the role of oxidative stress in caspase activation and subsequent apoptotic cell death after cerebral ischemia is unknown. The authors evaluated the role of oxidative stress in ischemic cerebral infarction after photothrombosis and the relation between oxidative stress and caspase-related cell death 6 and 24 hours after ischemia with and without U-74389G, a potent free radical scavenger (10 mg/kg, 30 minutes before and after ischemia induction). Reactive oxygen species, detected by hydroethidine oxidation, and cytosolic cytochrome c were detected in early ischemic lesions. Western blot analysis showed the cleaved form and the increased level of the proform of caspase-3 in the ischemic lesion 24 hours after ischemia. Decreased caspase-3 immunoreactivity was detected in the antioxidant-treated group after ischemia. Decreased DNA fragmentation and laddering were detected and the lesion was smaller in the treated group after ischemia compared with the untreated group. Oxidative stress and cytochrome c release occur in the ischemic lesion after photothrombotic ischemia. The free radical scavenger attenuated caspase-3 up-regulation, DNA fragmentation, and the final lesion. The authors concluded that oxidative stress may mediate caspase-related apoptotic cell death and subsequent cortical infarction after photothrombotic ischemia.     

脑缺血再灌注损伤后神经细胞巢蛋白和干细胞因子基因的表达★

背景：干细胞因子是缺氧诱导的神经再生因子，可能刺激动物的神经再生。 目的：观察大鼠脑缺血再灌注损伤后神经细胞巢蛋白和干细胞因子基因表达的变化，分析两者变化的时间规律。 设计：随机对照动物实验。 单位：青岛大学医学院附属医院超声诊断科。 材料：实验选用成年健康雌性SD大鼠36只，由中国科学院上海实验动物中心提供。实验所用巢蛋白和干细胞因子 mRNA原位杂交试剂盒、DAB试剂盒均由武汉博士德生物工程有限公司提供。 方法：实验于2005-01/06在山东省脑病防治重点实验室完成。选取32只大鼠，应用线栓法经左侧颈外一颈内动脉插线建立左侧大脑中动脉阻塞再灌注模型，在缺血1.5 h再灌注后2，6 ，1 2 ，24 h，2，3，7，14 d进行观察，每个时间点4只。其余4只为假手术组：除不插线外，其余步骤同实验组。应用原位杂交技术检测脑缺血再灌注后皮质、纹状体和室旁区巢蛋白和干细胞因子mRNA的表达。 主要观察指标：大鼠皮质、纹状体和室旁区神经细胞巢蛋白和干细胞因子基因表达。 结果：进入结果分析数量保持为36只。①巢蛋白 mRNA表达：假手术组皮质、纹状体和室旁区巢蛋白 mRNA表达很弱。缺血再灌注后，在皮质中的表达除再灌注后2 h、纹状体除再灌注后2,6 h以外，室旁区除2,6 h,14 d以外各时间点均明显高于假手术组，差异有显著性意义（P < 0.05）。②干细胞因子表达:假手术组皮质、纹状体和室旁区干细胞因子表达很弱。缺血再灌注后，在皮质中的表达除2,6,12 h以外，纹状体除2,6 h以外，室旁区除2 h,14 d以外各时间点均明显高于假手术组，差异有显著性意义（P < 0.05）。 结论: 干细胞因子表达的时间规律与神经干细胞增殖的时间规律基本一致，可以提示脑缺血再灌注后干细胞因子 mRNA表达可能具有促进神经干细胞增殖作用。     

Endoplasmic reticulum in the penumbra following middle cerebral artery occlusion in the rabbit

Caspase-12 has been localized to endoplasmic reticulum (ER) and showed to involve ER stress-induced apoptosis. In the present work we investigated the temporospatial alterations of caspase-12 immunoreactivity in the penumbra following cerebral ischemia/reperfusion in rabbit. Transient cerebral ischemia was produced by intraluminal occlusion of the middle cerebral artery for 2 h followed by 1 h, 6 h, 1 day, 3 days, 7 days and 14 days of reperfusion. Caspase-12 immunohistochemistry was first increased in the penumbra 1 h after reperfusion, with a peak at day 1 to day 3, and then gradually decreased to basal level at day 14. The number of TUNEL-positive cells and ultrastructural observation of brain sections in the penumbra showed a similar change at the same time points. ER mediated by caspase-12 participated in apoptosis induced by cerebral ischemia/reperfusion injury, which may provide a new area for therapeutic intervention to ameliorate outcomes following cerebral ischemia.     

Glial Damage After Transient Focal Cerebral Ischemia in Rats

We investigated the immunohistochemical changes of 8-hydroxy-2′-deoxyguanosine (8-OHdG) immunoreactivity as a marker of DNA damage and single-strand DNA (ssDNA) immunoreactivity as a marker of apoptosis in the striatum from 1 up to 15 days after 90 min of focal cerebral ischemia caused by middle cerebral artery occlusion in rats. In the present study, marked loss of MAP2 immunostaining was observed in the ipsilateral striatum 3 days after focal cerebral ischemia. A significant increase in the number of ssDNA-immunoreactive apoptotic neurons was observed in the ipsilateral striatum 1 and 3 days after focal cerebral ischemia. In contrast, a significant increase in densities of 8-OHdG-immunopositive cells was observed in the ipsilateral striatum from 3 up to 15 days after focal cerebral ischemia. Our double-labeled immunochemical study showed that 8-OHdG immunoreactivity was observed in both isolectin B₄-positive microglia and glial fibrillary acidic protein-immunopositive astrocytes in the ipsilateral striatum 7 days after focal cerebral ischemia. These results suggest that focal cerebral ischemia can cause a marked increase in the number of microglia and astrocytes with oxidative DNA damage in the ipsilateral striatum. Furthermore, our results show that most microglia and astrocytes in the ipsilateral striatum after focal cerebral ischemia may not die by apoptosis. Thus, our findings provide novel evidence that focal cerebral ischemia can cause oxidative DNA damage in most microglia and astrocytes.