Patterns of growth inhibitory factor (GIF) and glial fibrillary acidic protein relative level changes differ following left middle cerebral artery occlusion in rats

Growth inhibitory factor (GIF) has been identified as a new metallothionein-like protein, the level of which is decreased in the Alzheimer's disease brain. GIF and glial fibrillary acidic protein (GFAP) have been reported to be expressed in reactive astrocytes in the rat brain following stab wounds. Moreover, strong expression of GIF mRNA in reactive astrocytes after ventricular injection of kainic acid has been demonstrated. To clarify the biological functions of GIF and GFAP in repair of the CNS, we examined changes in their relative levels to sham control using a Western blotting technique in the rat left hemisphere following occlusion of the left middle cerebral artery, for 28 days after surgery. The GIF relative level declined to 56% of the sham-operated control value on day 7. Thereafter the GIF relative level increased and returned to the normal relative level by days 21–28. The GFAP relative level increased from day 3 and reached a maximum of 120% of the sham-operated control value on days 14–21. While GIF and GFAP were both detected in reactive astrocytes, an increase in the GFAP relative level occurred prior to an increase in GIF relative level following the ischemia. The patterns of changes in relative expression levels of GIF and GFAP were quite similar to those in our previous studies on effects of cerebral stab wounds in rats, although the changes were more rapid in the previous studies. GIF and GFAP appear to play different roles in the repair of the CNS. The present results also indicated that GIF could play an important role in CNS repair after cerebral ischemia and provide new insights into the mechanism of gliosis investigated mainly from the viewpoint of GFAP.     

胶质纤维酸性蛋白在老年痴呆大鼠海马中的表达

为探讨慢性缺血痴呆鼠学习减退与海马内星形胶质细胞表达的关系,基于老年大鼠慢性脑缺血痴呆模型,采用免疫组化技术及迷宫实验,定量分析海马星形胶质细胞变化与学习能力、记忆能力的关系。结果发现,慢性缺血痴呆鼠海马CAl区GFAP阳性细胞数目明显增多,胞体肥大,突起增粗、变长,与对照组相比有显著意义(P<0.05),Y型迷宫测试结果显示,痴呆组大鼠的学习、记忆能力与对照组相比,明显下降。提示海马星形胶质细胞可能参与慢性缺血痴呆大鼠的学习记忆功能。     

Development of glial fibrillary acidic protein immunoreactivity in thyroidectomized rats

The majority of astroglia develop postnatally in rats. GFAP (glial fibrillary acidic protein)-immunoreactivity appears mainly during the 2nd and 3rd postnatal weeks throughout the brain. Hypothyroidism inhibits, among others, the cell proliferation, maturation, and migration of neurons. However, hardly any data on the effect of hypothyroidism on GFAP-immunoreactivity are available in the literature. In our experiments, thyroidectomy was performed between the 3rd and 5th postnatal days. Operated and control animals from the same litter were perfused transcardially and processed for immunohisto-chemistry in parallel after 2, 3, and 4 wk. On the basis of serial sections, the development of GFAP-immunoreactivity was not generally affected by hypothyroidism. We could observe only two phenomena that showed a tendency of retardation in the operated animals: (1) the decrease of the strong GFAP-immunopositivity of white matter tracts (for example, internal capsule and pyramidal tract) and (2) the gradual disappearance of the GFAP-immunoreactive radial fibers (for example, in the neocortex, in the olfactory bulb, and around the 3rd ventricle).     

缺血后海马高迁移率族蛋白与星形胶质纤维酸蛋白表达及相关性

目的研究大鼠局灶性脑缺血再灌注星形胶质纤维酸蛋白(GFAP)与高迁移率族蛋白(HMGB1)在海马CA1区表达变化,探讨二者之间的关系。方法采用大脑中动脉栓塞2h制备SD大鼠脑缺血模型,60只雄性SD大鼠随机分为假手术组、缺血再灌注组,按1d、3d、7d、14d、28d时间点再分5个亚组,各时间点处死取脑,用免疫组化和荧光双标结合共聚焦扫描的方法来检测高迁移率族蛋白和星形胶质纤维酸蛋白在脑内海马CA1区表达变化。结果不同时间点缺血再灌注组GFAP、HMGB1表达均高于同时期的假手术组(P<0.05)。缺血再灌注组星形胶质细胞1d、3d、7d逐渐激活增生,7d达到高峰,14d开始下降;HMGB1在1d、3d、7d、14d是表达增加,14d达高峰,28d下降(与前一时间点比较P<0.05)。缺血再灌注组GFAP和HMGB1表达具有相关性(P<0.05),存在HMGB1和GFAP共定位细胞。结论脑缺血再灌注后,海马CA1区HMGB1增加与星形胶质细胞激活成正相关,过度表达的HMGB1和增殖的星形胶质细胞可能与缺血再灌注后神经元的迟发性损伤有关。     

Cerebrospinal fluid neurofilament and glial fibrillary acidic protein in patients with cerebral vasculitis

Few diseases in clinical medicine cause as much diagnostic consternation as central nervous system (CNS) vasculitis because of its varying modes of presentation and frequently overlapping clinical and pathological features. There are no pathognomonic clinical or laboratory findings. The purpose of the present retrospective study was to validate the use of the light subunit of neurofilament triplet protein (NFL) and glial fibrillary acidic protein (GFAP) as markers of CNS tissue damage for patients with systemic or isolated CNS vasculitis. Levels of cerebrospinal fluid (CSF) NFL and GFAP were measured using ELISAs. Both CSF NFL and CSF GFAP concentrations were significantly higher in a patient group diagnosed with CNS vasculitis (P < 0.01 and P < 0.05, respectively) than in a patient group for whom CNS vasculitis was excluded. In the future, analysis of CSF NFL in particular, but also GFAP, may be a useful complement in the difficult clinical task of diagnosing CNS vasculitis.     

Developmental changes of glial fibrillary acidic protein in cerebral white matter

Developmental changes were observed in the glial fibrillary acidic protein (GFAP)--positive glia of cerebral white matter (including myelination glia) in the frontal lobes of 38 normal cases. With age, GFAP-positive processes gradually became larger and their location shifted from preponderantly in the deep white matter to mostly in the superficial white matter. This shift in pattern of GFAP-positive glia may be related to the parallel changes in perinatal brains in the localization of leukomalacic lesions. However, the shift is a normal developmental phenomenon on which such lesions are superimposed.     

中药薏苡仁和100Hz电针干预脊髓半横断性大鼠可降低损伤后胶质纤维酸性蛋白表达

实验建立正常对照组、假手术组、高低频电针组和中药薏苡仁干预组,横断T10左半侧的脊髓损伤模型大鼠,4h后使用5,100Hz电针刺激环跳(GB30)、足三里(ST 36)、至阳(DU9)及悬枢(DU5)或腹腔注射0.4μL中药薏苡仁粗提液(与生药比例为1:1),连续8周,观察发现低高频电针刺激及薏苡仁治疗能改善脊髓组织损伤区域形态,促进运动诱发电位的恢复,抑制损伤区胶质纤维酸性蛋白表达,改善半横断性脊髓损伤大鼠运动功能,以100Hz电针刺激和薏苡仁干预效果明显。     

Phosphorylation of the glial fibrillary acidic protein

The glial fibrillary acidic protein (GFAP) was found to be phosphorylated in vivo after intracerebral injection of [³²P]-orthophosphate, in brain Slices, and in a cell free system. The phosphorylated proteins were separated by two-dimensional gel electrophoresis and then transferred to nitrocellulose sheets. Two isoelectric variants of GFAP were immunochemically identified by monoclonal antibodies. Autoradiography demonstrated that only the more acidic isoelectric variant of GFAP was phosphorylated. Phosphoamino acid analysis revealed that under all conditions GFAP was phosphorylated at serine and threonine residues. Incubation of brain slices with[³²P]-orthophosphate and the protein kinase C activator phorbol 12-myristate 13-acetate or forskolin, an activator of cyclic AMP-dependent protein kinase, stimulated phosphorylation of GFAP. Likewise phosphorylation of GFAP was also accentuated by calcium/phosphatidylserine/diolein and by exogenous cyclic AMP-dependent kinase in a cell free system. These findings announce that protein kinase C and cyclic-AMP dependent kinase may play physiologic roles in the in situ phosphorylation of GFAP. When isolated cytoskeletal preparations were incubated with [γ-³²P] ATP, GFAP was phosphorylated in vitro by two additional protein kinases, a Ca⁺⁺/calmodulin-depen-dent kinase and an effector-independent kinase. The results of these investigations strongly suggest that phosphorylation of GFAP appears to be regulated by multiple second messenger pathways.     

An increase in glial fibrillary acidic protein follows brain hyperthermia in rats

Previously, we have demonstrated that an increase in the astrocyte-associated protein, glial fibrillary acidic protein (GFAP), accompanies brain injury induced by a variety of chemical insults. In the present study we examined the effects of microwave-induced hyperthermia of the CNS on the concentration of GFAP in several brain regions of the Long-Evans rat. Irradiation resulted in a time-related increase in GFAP in olfactory bulbs and cortex, areas of maximum heating. The increase in GFAP following a brain temperature increase suggests that heating of brain tissue may be sufficient to provoke an injury response comparable to that induced by chemical and physical insult.     

Effect of erhuangfang on cerebral and spinal demyelination and regeneration as well as expression of glial fibrillary acidic protein in rats with experimental allergic encephalomyelitis

BACKGROUND: It demonstrates that erhuangfang can improve clinical symptoms of multiple sclerosis and relieve side effects of hormone. However, whether erhuangfang can improve experimental allergic encephalomyelitis (EAE) or not needs a further study. OBJECTIVE: To observe the effect of erhuangfang on neuro-pathology and astrocyte in EAE rats and compare with the effect of hormone. DESIGN: Randomized controlled animal study. SETTINGS: Department of Traditional Chinese Medicine, Beijing Tiantan Hospital, Capital Medical University; College of Traditional Chinese Medicine, Capital Medical University. MATERIALS: The experiment was carried out in the Laboratory Center of Capital Medical University from August to October 2005. Ten adult guinea pigs (SPF grade, weighing 400–450 g) and 70 adult Lewis rats (SPF grade, weighing 200–220 g) were selected in this study. Erhuangfang consisted of jiudahuang, shengdi, shuizhi, dabeimu, etc. METHODS: ① Experimental intervention: Rats were randomly divided into normal group (n=10), model group (n=20), western medicine group (n=20) and Chinese herb group (n=20). Mixed emulsion, which was consisted of Freund's adjuvant and spinal cord homogenate of guinea pigs, was subcutaneously injected into palms of the two hindfeet of rats in the latter three groups to establish EAE models. Foot pads were injected with saline and then rats were perfused with saline in the normal group. In the model group, models were established as the same as those mentioned above, and rats were also perfused with saline. Rats in the western medicine group were perfused with saline and then 5 mg/kg prednisone acetate suspension. Rats in the Chinese herb group were perfused with erhuangfang decoction (15 g raw materials per kilogram) at 5 days before model establishment. The dosage in the four groups was 3 mL/day per rat. ② Experimental evaluation: At 28 days after model establishment, rats were randomly selected for cerebral (mainly surrounding cerebral ventricle) and spinal cord (cervical enlargement and lumbar enlargement) collections, and then haematine-eosin (HE) staining and SLG myelin staining were used to observe demyelination and regeneration; meanwhile, immunohistochemical staining was used to observe the expression of glial fibriliary acidic protein (GFAP). MAIN OUTCOME MEASURES: Cerebral and spinal demyelination and regeneration as well as expression of GFAP in EAE rats. RESULTS: All 70 Lewis rats were involved in the final analysis. ① Demyelination and regeneration: Infiltration of inflammatory cells surrounding cerebrum and small venous vessels of spinal cord white matter, demyelination surrounding vessels and plentiful foam cells at myelinolysis sites were observed in the model group. Symptoms were relieved in the western medicine group and the Chinese herb group as compared with those in the model group. While, numbers of inflammatory infiltrated cells and vascular cuffs were decreased in focal region as compared with those in the model group; in addition, areas of softening focus and demyelination were decreased. ② Expression of GFAP: Volumes and numbers of positive cells of GFAP in white matter region were respectively bigger and higher than those of normal cells in the model group. Plentiful positive cells of GFAP were disorderly aggregated in hippocampus and surrounding small vessel cuffs. While, expression of GFAP was mildly increased surrounding focus in the Chinese herb group; however, GFAP did not express surrounding focus in the western medicine group. In addition, expressions of GFAP were not increased in non-focal region in both Chinese herb group and western medicine group. CONCLUSION: Both erhuangfang and hormone can relieve inflammatory reaction of central nervous system and demyelination of EAE rats. On one hand, erhuangfang can regulate reaction of astrocyte in two ways, relieve reaction and proliferation of astrocyte in non-focal region and maintain the protective effect of astrocyte on brain tissue in focal region; on the other hand, hormone can overall inhibit reaction of astrocyte.     

亚低温对大鼠脑缺血再灌注损伤后热休克蛋白70及胶质纤维酸性蛋白表达的影响

目的观察亚低温对大鼠脑缺血再灌注损伤后热休克蛋白70(HSP70)及胶质纤维酸性蛋白(GFAP)表达的影响。方法将雄性Wistar大鼠30只分为假手术组、常温组和亚低温组。制作右侧大脑中动脉阻塞(MCAO)模型,观察缺血2h再灌注48h后各组大鼠脑组织学改变和HSP70及GFAP的表达。结果常温组大鼠脑皮质下神经元严重坏死,亚低温组皮质下神经元坏死严重程度明显较常温组轻,假手术组未见神经元坏死。常温组大鼠脑组织GFAP和HSP70阳性细胞较多,假手术组、亚低温组GFAP和HSP70阳性细胞少于常温组,假手术组偶见HSP70阳性细胞;图像分析显示,常温组大鼠脑组织GFAP、HSP70表达的平均光密度较假手术组和亚低温组明显增高(均P<0.01)。结论亚低温能减轻大鼠脑缺血再灌注损伤,降低脑组织HSP70及GFAP蛋白的表达。     

5,7-Dihydroxytryptamine injections increase glial fibrillary acidic protein in the hypothalamus of adult rats

The distribution and levels of glial fibrillary acidic protein (GFAP) were determined in the adult rat hypothalamus following axotomy of serotonin (5-HT) neurons. Seven days after unilateral intrahypothalamic injection of the 5-HT neurotoxin, 5,7-dihydroxytryptamine, there was a marked increase in the number of GFAP-labelled astrocytes in the ipsilateral hypothalamus of 5,7-DHT-treated as compared to sham-treated rats. In addition, levels of GFAP were significantly increased 7 days after 5,7-DHT injection.     

辛醇预处理对红藻氨酸诱导的癫疒间大鼠海马神经元凋亡和胶质纤维酸性蛋白表达的影响

目的观察缝隙连接阻断剂辛醇预处理对红藻氨酸(KA)诱导的癫疒间大鼠海马神经元凋亡和胶质纤维酸性蛋白(GFAP)表达的影响。方法 160只雄性SD大鼠随机分为KA组、辛醇组、生理盐水(NS)组和二甲基亚砜(DMSO)组,应用KA右侧杏仁核注射制作癫疒间大鼠模型;制模前30 min辛醇组腹腔注射辛醇溶液;制模后3 h、6 h、12 h、24 h和7 d应用原位末端标记(TUNEL)法和免疫组化染色法分别检测各组大鼠海马CA3区TUNEL和GFAP阳性细胞数。结果 KA组制模后6 h海马CA3区有TUNEL阳性细胞表达,并逐渐增多,7 d达高峰;辛醇组制模后在6 h～7 d TUNEL阳性细胞数明显少于KA组(均P<0.01);KA组海马CA3区GFAP阳性细胞数随时间而逐渐增多,各时间点明显多于辛醇组(均P<0.01)。结论辛醇神经保护作用的机制可能与抑制细胞缝隙连接间通讯,切断凋亡信号传播,以减少神经元凋亡有关。     

辛醇预处理对红藻氨酸诱导的癫(癎)大鼠海马神经元凋亡和胶质纤维酸性蛋白表达的影响

目的 观察缝隙连接阻断剂辛醇预处理对红藻氨酸(KA)诱导的癫(癎)大鼠海马神经元凋亡和胶质纤维酸性蛋白(GFAP)表达的影响.方法 160只雄性SD大鼠随机分为KA组、辛醇组、生理盐水(NS)组和二甲基亚砜(DMSO)组,应用KA右侧杏仁核注射制作癫(癎)大鼠模型;制模前30 min辛醇组腹腔注射辛醇溶液;制模后3h、6h、12 h、24 h和7d应用原位末端标记(TUNEL)法和免疫组化染色法分别检测各组大鼠海马CA3区TUNEL和GFAP阳性细胞数.结果 KA组制模后6h海马CA3区有TUNEL阳性细胞表达,并逐渐增多,7d达高峰;辛醇组制模后在6 h～7 d TUNEL阳性细胞数明显少于KA组(均P＜0.01);KA组海马CA3区GFAP阳性细胞数随时间而逐渐增多,各时间点明显多于辛醇组(均P＜0.01).结论 辛醇神经保护作用的机制可能与抑制细胞缝隙连接间通讯,切断凋亡信号传播,以减少神经元凋亡有关.     

Expression of mRNA for glial fibrillary acidic protein after experimental cerebral injury.

This study was undertaken to determine whether a mRNA for glial fibrillary acidic protein (GFAP) was present in increased amounts as a response to injury and, if so, how was its temporal expression related to the demonstration of GFAP by immunocytochemical techniques. A cerebral freeze-injury was produced in mice and at intervals thereafter the animals were anesthetized, perfused with formalin and histological sections of the brain through the injured area were prepared. A riboprobe for GFAP mRNA labeled with S35 and an immunocytochemical probe for GFAP were utilized to localize mRNA and GFAP immunoreactivity, respectively. For mRNA studies, the histological slide exposed to either sense or antisense probe was overlaid with x-ray film or dipped in photographic emulsion. The developed film was quantitated by digital image analysis. Emulsions were examined by dark-field microscopy. The results indicate that mRNA for GFAP is increased in the cortex in the environs of the injury by 6 hours, becomes maximal at 4-5 days, and is present in increased amounts up to 14 days. The message is enhanced in the adjacent cortex, the subpial region, the adjacent corpus callosum and in the ipsilateral and contralateral callosal radiations. This pattern of enhancement follows the distribution of post-injury edema. Glial fibrillary acidic protein is demonstrable at 24-48 hours after injury. Thus, there is a rapid response of the astrocyte to injury with increased mRNA expression that is followed by expression of GFAP immunoreactivity.     

脊髓损伤模型大鼠神经胶质细胞增殖与胶质纤维酸性蛋白的表达

背景：星形胶质细胞可以通过细胞裂解释放各种神经营养因子,并可促进损伤脊髓的修复。 目的：观察脊髓损伤模型大鼠神经胶质纤维酸性蛋白的表达及对其后肢功能恢复的影响。 方法：将SD大鼠采用Allen's法撞击T9~10节段致脊髓损伤,造模成功后蛛网膜下腔移植骨形态发生蛋白7,并设置仅蛛网膜下腔移植His蛋白的正常SD大鼠做对照。用BBB评分法评估两组大鼠后肢的运动功能,用免疫组织化学染色法和Western-blot法观察各组神经胶质纤维酸性蛋白的表达。 结果与结论：BBB评分结果显示,模型组大鼠脊髓损伤后下肢功能自行恢复率达68%。模型组脊髓损伤3和7 d,损伤区域神经胶质纤维酸性蛋白表达逐渐增加(P < 0.05),随后逐渐下降,于脊髓损伤28 d后逐渐恢复到对照组水平(P > 0.05)。脊髓损伤后1~14 d两组胶质纤维酸性蛋白表达逐渐升高(P > 0.05)。结果证实,脊髓损伤后蛛网膜下腔移植骨形态发生蛋白7可诱导星形胶质细胞增殖,神经胶质纤维酸性蛋白的表达增强,进而促进脊髓损伤大鼠后肢功能的恢复。