小胶质细胞与胶质瘤免疫

目前,恶性胶质瘤治疗效果不佳,死亡率极高,特别是多形性胶质母细胞瘤,即使给予综合治疗,中位生存期也只有14个月^[1]研究^[2]发现,胶质瘤中浸润有大量的小胶质细胞,这些小胶质细胞既出现在未受损的肿瘤组织中,也出现在坏死区域,并且他们的浸润程度与胶质瘤的级别和侵袭性密切相关。     

小胶质细胞活化在脑缺血耐受中的双重作用

目的 观察局灶性缺血预处理对小胶质细胞活化的影响,探讨小胶质细胞在内源性神经保护机制中的作用.方法 48只SD大鼠按随机数字表法分为空白对照组(SS+SS)、缺血预处理组(IPC+SS)、假手术+缺血组(SS+MCAO)、缺血预处理+再缺血组(IPC+MCAO),每组各12只.运用TTC染色、组织化学染色、透射电镜和图像方法分析比较各组大鼠梗死灶体积、超微结构及小胶质细胞活化的变化.结果 与SS+MCAO组相比,IPC+MCAO组脑梗死灶体积明显缩小,比较差异有统计学意义(P＜0.05),超微结构改变较轻.IPC+MCAO组及SS+MCAO组的小胶质细胞活化水平均较IPC+SS组增高,但二者相比,IPC+MCAO组明显低于SS+MCAO组,比较差异有统计学意义(P＜0.05).结论 小胶质细胞活化在脑缺血耐受中具有双重作用,其介导的轻微炎性过程可能是局灶性缺血预处理启动内源性神经保护的重要分子机制.     

大鼠束缚后脑内小胶质细胞的反应

目的　 探讨大鼠束缚后脑内小胶质细胞的反应及其时程变化。 方法　 将大鼠束缚于小的塑料桶内 1,3或 6h ,于解束后 30min被处死 ,脑组织进行抗OX4 2 (小胶质细胞的特异性标记物 )免疫组织化学染色。结果 　正常大鼠脑内的小胶质细胞一般为静息状态 (静息型 ) ,其特点是OX4 2为阴性或浅染 ,在切片上不易发现或细胞形态不清晰。束缚 1h后 ,小胶质细胞为轻度反应 ,OX4 2浅染 ,细胞形态隐约可见 ,仅于下丘脑的视上核、室旁核和弓状核有散在的表达。束缚 3h后 ,小胶质细胞的反应达到高峰 ,由静息状态变为早期反应状态 (早期反应型 ) ,OX4 2深染 ,细胞形态清楚 ,突起上可见到小棘。早期反应型小胶质细胞广泛分布于前脑 :扣带回、新皮质浅层、隔外侧核、海马CA3、齿状回、杏仁中央核 ;间脑 :下丘脑视前区、视上核、室旁核、第三脑室周区、弓状核、丘脑室旁核、外侧膝状体、内侧膝状体 ;脑干 :中脑的上丘视性层、中脑导水管周围灰质、下丘的皮质部 ;脑桥的外侧臂旁核、蓝斑、A5区 ;延髓的延髓内脏带 (MVZ)和三叉神经脊束核等处 ;束缚 6h后 ,小胶质细胞反应减弱 ,OX4 2浅染 ,分布范围减少 ,主要出现于扣带回、隔外侧核、海马、视上核、室旁核、中脑导水管周围灰质、脑桥的臂旁外侧核、蓝斑、延髓的延髓内脏带 (M     

实验性自身免疫性脑脊髓炎的小胶质细胞和星形胶质细胞反应

目的确定小胶质细胞和星形胶质细胞在实验性自身免疫性脑脊髓炎（ＥＡＥ）发病及病变发展中的作用。方法用牛脊髓髓鞘碱性蛋白（ＭＢＰ）免疫豚鼠发生ＥＡＥ,用免疫组化法观察ＥＡＥ不同病期小胶质细胞和星形胶质细胞对炎性脱髓鞘病灶的反应。结果发生ＥＡＥ的前３天,小胶质细胞即开始激活,在临床症状出现时其数量及激活程度达高峰,并持续至高峰期。恢复期数量逐渐减少,激活程度逐渐减弱。星形胶质细胞在症状高峰期开始激活并围绕在浸润细胞和病变血管周围,似有隔离小胶质细胞与病灶接触的作用,至恢复期激活明显。结论小胶质细胞激活在ＥＡＥ的发病及进展中起重要作用,而星形胶质细胞主要与疾病的恢复有关。     

大鼠脑创伤后小胶质细胞激活的时程及形态变化研究

目的探讨大鼠脑创伤后小胶质细胞激活的时程及形态变化。方法采用改良的Feeney等人的方法造成大鼠颅脑损伤模型,21只SD大鼠随机分为对照组和创伤组,后者根据伤后处死时间点不同,再分为伤后1h,6h,12h,24h,48h和72h组,每组动物3只,在伤后不同时间点处死动物,取伤区脑组织行抗OX-42免疫组织化学染色。结果正常大鼠脑内小胶质细胞一般为静息状态,OX-42为阴性,在切片上不易发现或细胞形态不清晰;伤后1h,小胶质细胞为轻度反应,OX-42浅染,细胞形态隐约可见,不规则;伤后6h,小胶质细胞反应明显,由静息状态变为早期反应状态,OX-42深染,细胞形态清楚;伤后12h,小胶质细胞反应达高峰,细胞形态更清楚,突起上可见到小棘;24h以后,反应减弱,OX-42浅染,细胞数量减少。结论大鼠脑创伤后小胶质细胞被激活,细胞形态发生改变,海马区亦有激活改变;反应的时程变化是伤后1h出现激活,6h反应明显,12h达高峰,以后逐渐减弱。     

LPS激发大鼠前脑神经元Fos和小胶质细胞OX42表达改变

目的 探讨单次腹腔注射LPS后前脑神经元和小胶质细胞的可塑性变化和相互关系。方法 应用抗Fos、抗TH或抗OX42单一、以及抗Fos／抗TH／抗OX42三重免疫组化标记方法，观察大鼠单次腹腔注射LPS后，Fos阳性神经元、Fos／TH阳性神经元、OX42阳性小胶质细胞在脑内的表达分布及时程变化，以及Fos阳性神经元或Fos／TH阳性神经元与OX42阳性小胶质细胞之间的关系。结果：Fos阳性神经元分布在额、顶皮质，扣带回和梨状皮质，外侧隔核腹侧部，杏仁中央核，海马CA2区、CA3区、齿状回，下丘脑室旁核、视上核、下丘脑外侧区和第三脑室周围灰质等。Fos阳性神经元在注射后30min出现表达，注射后1～3h为表达高峰。反应阳性小胶质细胞首先于脑室周围灰质出现，注射后6h达到高峰，胞体变大，突起变粗，OX42呈阳性深染，密集分布于Fos阳性神经元的表达区域。下丘脑Fos／TH／OX42三重染色切片显示：由LPS激活的Fos／TH阳性神经元周围被OX42阳性细胞包绕并接触，表明神经元和小胶质细胞在对LPS刺激的反应中关系密切。结论 在外周免疫刺激下，下丘脑、扣带回、梨状皮质和海马内的神经元和小胶质细胞可能参与免疫调节。     

芹黄素抑制小胶质细胞活化作用研究

目的探讨芹黄素对小胶质细胞活化的抑制作用。方法原代培养SD大鼠小胶质细胞,实验随机分为空白对照组、脂多糖组(LPS组)、LPS+芹黄素(10μM)组、LPS+芹黄素(20μM)组、LPS+芹黄素(50μM)组。MTT法检测芹黄素对小胶质细胞活性的影响;ELISA法检测IL-1、IL-10等炎症相关因子以及BDNF、PDNF等神经营养因子的表达;RTPCR、western blot检测炎症相关基因i NOS转录以及表达水平。结果 MTT检测结果表明,芹黄素对小胶质细胞活性无明显抑制。LPS刺激后,芹黄素预处理组IL-1等炎症因子表达水平明显低于单独LPS组(P0.05);而芹黄素预处理组IL-10的表达则高于单独LPS组(P0.01);与此同时,BDNF、PDNF等神经营养因子的分泌也有相同趋势(P0.05)。芹黄素预处理组i NOS表达和转录水平也低于单独LPS组(P0.05)。结论芹黄素可抑制活化状态小胶质细胞炎症因子以及炎症相关蛋白的表达,并可同时促进与神经元分化成熟相关神经营养因子的分泌。     

ROCK抑制剂Y27632对小胶质细胞活化增殖和细胞周期的影响

目的观察ROCK抑制剂Y27632对小胶质细胞活化增殖和细胞周期的影响。方法采用小胶质细胞系BV2细胞复苏后传代培养,分为对照组和Y27632干预组;在不同时间点(0、3、6、12、和24h),采用brdu标记法和流式细胞术检测各实验组细胞增殖率变化及细胞周期进展情况。结果干预3h后各组的S期细胞率都逐渐增加,但Y27632干预组的S期细胞率较正常组明显增加,6h时达高峰(P<0.01);Brdu掺入法显示干预6h时BV2细胞的增殖活力最高,在各个时间点Y27632干预组的Brdu阳性率都较对照组高,6h时最为显著(P<0.01)。结论 ROCK抑制剂Y27632可促进小胶质细胞系BV2细胞的活化增殖和细胞周期进展,提示Rho/ROCK信号通路在小胶质细胞的增殖过程中起着重要的作用。     

小鼠脑出血后不同时间点小胶质细胞极化状态的实验研究

目的 观察小鼠脑出血后不同时间点小胶质细胞M1及M2型的转化,为促炎型M1型小胶质细胞向抗 炎修复型M2型小胶质细胞的转化,减轻脑出血后神经功能损伤提供理论依据。 方法 选取健康雄性ICR小鼠48只,随机分为假手术组、脑出血组,每组按术后时间点不同随机 分为1 d、3 d、7 d三个时间点,每个时间点8只。通过立体定位仪用微量注射器向尾状核注射Ⅳ型胶 原酶0.5 U制备脑出血模型,假手术组注射等量生理盐水。各组于术后对应时间点参照改良Garcia 评分量表进行神经功能缺损评分后灌注取脑,采用蛋白免疫印迹检测M1型小胶质细胞标志物肿瘤 坏死因子α（tumor necrosis factor-α,TNF-α）、白细胞介素6（interleukin-6,IL-6）,M2型小胶质细胞 标志物脑源性神经营养因子（brai n-derived neurotrophic factor,BDNF）、胰岛素样生长因子1（insulinlike growth factor 1,IGF-1）的含量;采用免疫荧光染色标记小胶质细胞M1型（Iba1+CD80）、M2型 （Iba1+CD206）,评价出血后血肿周围组织小胶质细胞活化状态。 结果 脑出血组1 d、3 d、7 d各时间点Garci a评分均较假手术组低,TNF-α、IL-6、BDNF及I GF-1的蛋白 表达量均较假手术组增多（均P＜0.01）。脑出血后1 d时M1型高于M2型小胶质细胞数量（38.33±1.53 vs 23.00±3.00,P =0.01）;3 d时M1型同样高于M2型（66.33±3.06 vs 57.33±2.52,P =0.02）;7 d时M1 型低于M2型（33.67±1.15 vs 52.33±0.58,P＜0.01）。 结论 脑出血急性期（1～3 d）以M1型小胶质细胞为主,脑出血亚急性期（7 d）以M2型小胶质细胞 为主。     

小鼠脑出血后不同时间点小胶质细胞极化状态的实验研究

目的 观察小鼠脑出血后不同时间点小胶质细胞M1及M2型的转化，为促炎型M1型小胶质细胞向抗
炎修复型M2型小胶质细胞的转化，减轻脑出血后神经功能损伤提供理论依据。
方法 选取健康雄性ICR小鼠48只，随机分为假手术组、脑出血组，每组按术后时间点不同随机
分为1 d、3 d、7 d三个时间点，每个时间点8只。通过立体定位仪用微量注射器向尾状核注射Ⅳ型胶
原酶0.5 U制备脑出血模型，假手术组注射等量生理盐水。各组于术后对应时间点参照改良Garcia
评分量表进行神经功能缺损评分后灌注取脑，采用蛋白免疫印迹检测M1型小胶质细胞标志物肿瘤
坏死因子α（tumor necrosis factor-α，TNF-α）、白细胞介素6（interleukin-6，IL-6），M2型小胶质细胞
标志物脑源性神经营养因子（brai n-derived neurotrophic factor，BDNF）、胰岛素样生长因子1（insulinlike
growth factor 1，IGF-1）的含量；采用免疫荧光染色标记小胶质细胞M1型（Iba1+CD80）、M2型
（Iba1+CD206），评价出血后血肿周围组织小胶质细胞活化状态。
结果 脑出血组1 d、3 d、7 d各时间点Garci a评分均较假手术组低，TNF-α、IL-6、BDNF及I GF-1的蛋白
表达量均较假手术组增多（均P＜0.01）。脑出血后1 d时M1型高于M2型小胶质细胞数量（38.33±1.53
vs 23.00±3.00，P =0.01）；3 d时M1型同样高于M2型（66.33±3.06 vs 57.33±2.52，P =0.02）；7 d时M1
型低于M2型（33.67±1.15 vs 52.33±0.58，P＜0.01）。
结论 脑出血急性期（1～3 d）以M1型小胶质细胞为主，脑出血亚急性期（7 d）以M2型小胶质细胞
为主。     

Tubulization Increases Axonal Outgrowth of Rat Sciatic Nerve after Crush Injury

It is important to develop methods which increase nerve regeneration since restoration of function following injury to peripheral nerves often requires outgrowth of the injured axons over long distances. In this study, axonal outgrowth after bilateral crush injury to the sciatic nerve of the rat was measured. One group with large-diameter nonpermeable silicone tubes and one group with large-diameter permeable silicone tubes applied around the crush site on one side had regeneration following nerve injury compared to controls on the other side. The length of regeneration of the regenerating axons were then measured 4, 5, and 6 days following the crush injury using the “pinch reflex test.” The presence of axons at the pinch level was confirmed by immunocytochemical staining for neurofilaments. The length of regeneration for rats with nonpermeable tubes was significantly greater than that of the contralateral control side and was so at all times (p < 0.05). The effect was present but not that pronounced where permeable tubes were used. We conclude that the outgrowth of regenerating sensory axons after sciatic nerve crush injury in the rat can be increased by enclosing the regeneration site in a silicone tube. The observed effect may be due to local mechanisms such as macrophage invasion or prevention of rapid wash-out of fluid from the crush zone.     

猫慢性视神经压迫性损伤模型的构建

BACKGROUND： An animal model of chronic optic nerve injury is necessary to further understand the pathological mechanisms involved. OBJECTIVE： To establish a stabilized, chronic, optic nerve crush model, which is similar to the clinical situation to explore histopathological and optic electrophysiological changes involved in this injury. DESIGN, TIME AND SETTING： A randomized and controlled animal trial was performed at Shanghai Institute of Neurosurgery from May to October 2004, MATERIALS： A BAL3XRAY undetachable balloon and Magic-BD catheter were provided by BLAT, France; JX-2000 biological signal processing system by Second Military Medical University of Chinese PLA, China; inverted phase contrast microscopy by Olympus, Japan. METHODS： A total of twenty normal adult cats were randomly assigned to control （n = 5） and model （n = 15） groups, according to different doses of contrast agent injected through balloons as follows： 0.2 mL injection, 0.25 mL injection, and 0.35 mL injection, with each group containing 5 animals. Imitating the clinical pterion approach, the optic nerves were exposed using micro-surgical methods. An engorged undetachable balloon was implanted beneath the nerve and connected to a catheter. Balloon size was controlled with a contrast agent injection （0.1 mL/10 min） to form an occupying lesion model similar to sellar tumors. MAIN OUTCOME MEASURES： The visually evoked potential examination was used to study optical electrophysiology changes in pre-post chronic optical nerve injury. Ultrastructural pathological changes to the optic nerve were analyzed by electron microscopy. RESULTS： During the early period （day 11 after modeling）, visually evoked potential demonstrated no significant changes. In the late period （day 51 after modeling）, recorded VEP demonstrated that P1 wave latency was prolonged and P1 wave amplitude was obviously reduced. Following injury, the endoneurium, myelin sheath, lamella, axolemma, and axon appeared disordered. CONCLUSION： Results demonstrated that the chronic, intracranial, optical nerve crush model was stable and could simulate optic nerve lesions induced by sellar tumors. Under the condition of chronic optical nerve crush, visually evoked potentials were aggravated.     

Hyperbaric Oxygen Treatment Enhances Regeneration of the Rat Sciatic Nerve

The effect of hyperbaric oxygen (HBO) treatment on regeneration of the rat sciatic nerve was studied. The sciatic nerve was crushed with a pair of pliers and the animals were either left untreated or subjected to a series of 45-min exposures to 100% O₂at 3.3 atm absolute pressure at 0, 4, and 8 h postoperatively and then every 8 h. Regeneration was evaluated using the pinch-reflex test at 3, 4, or 5 days following surgery and with neurofilament staining at 4 days. The regeneration distances at all time points were significantly longer in animals exposed to hyperbaric oxygen treatment independent of the evaluation procedure. A short initial period of the same HBO treatment schedule, with no more treatments after 25 h, appeared as effective as when treatments were maintained being given every 8 h until evaluation. We conclude that HBO treatment stimulates axonal outgrowth following a nerve crush lesion.     

Submodality-Selective Hyperalgesia Adjacent to Partially Injured Sciatic Nerve in the Rat is Dependent on Capsaicin-Sensitive Afferent Fibers and Independent of Collateral Sprouting or a Dorsal Root Reflex

We studied submodality dependence of sensory changes produced by unilateral ligation of the sciatic or the saphenous nerve in the rat. We focused especially on sensory changes in the skin area adjacent to the innervation area of the injured nerve. Moreover, we examined the roles of capsaicin-sensitive nociceptive fibers, collateral sprouting and a dorsal root reflex in sensory changes observed behaviorally. Assessment of sensory changes was performed by a pattern of behavioral tests: hot-plate test and hindlimb withdrawal responses induced by radiant heat, hot-water bath, innocuous mechanical stimuli, and noxious mechanical stimuli. In one group, the saphenous nerve ipsilateral to the sciatic ligation was topically treated with capsaicin (1%) at the time of the surgery. A proximal stump of a saphenous nerve strand was orthodromically stimulated to induce a dorsal root reflex (an antidromic volley) in nociceptive fibers of the saphenous nerve trunk. For visualization of plasma extravasation induced by a dorsal root reflex, a dye-labeling (Evans blue) technique was used. A collateral sprouting of nociceptive fibers of the uninjured saphenous nerve was evaluated by determining the plasma extravasation response induced by antidromic stimulation of the saphenous nerve. Three and 10 days following the sciatic constriction injury, the hindlimb withdrawal threshold evoked by noxious mechanical stimulation of the medial side of the paw (the innervation are of the intact saphenous nerve) was significantly decreased. There was no corresponding thermal hyperalgesia adjacent to the injured sciatic nerve. Chronic constriction of the saphenous nerve did not produce any significant hyper- or hypoalgesia to mechanical or thermal stimulation of the uninjured sciatic nerve area. Topical treatment of the ipsilateral (intact) saphenous nerve at the time of the sciatic nerve ligation completely prevented the development of mechanical hyperalgesia in the medial side of the paw (the innervation area of the saphenous nerve). No dorsal root reflex in nociceptive fibers mediating the adjacent hyperalgesia could be evoked. No collateral sprouting of the uninjured nociceptive fibers of the saphenous nerve was observed. The results indicate that the constriction injury of the sciatic nerve produced a selective hyperalgesia to mechanical stimulation in the innervation area of the neighboring saphenous nerve. At the peripheral level, the mechanical hyperalgesia adjacent to the innervation area of the injured nerve was mediated by capsaicin-sensitive nociceptive fibers. Collateral sprouting of nociceptive fibers from the uninjured to the injured innervation area did not contribute to the present sensory findings. The sciatic nerve injury did not induce a dorsal root reflex in nociceptive fibers innervating the hyperalgesic saphenous nerve area.     

Peripheral Nerve Pathology Following Sciatic Cryoneurolysis: Relationship to Neuropathic Behaviors in the Rat

Sciatic cryoneurolysis (SCN) is an experimental rat mononeuropathy model that produces neuropathic behavioral sequelae distinct from other neuropathy models. Following SCN, there is limited autotomy peaking in severity and incidence at 7-14 days and delayed but sustained allodynia appearing at about 21 days, with no evidence of thermal hyperalgesia. This study quantified peripheral nerve pathology at weekly intervals following SCN to determine the relationship of nerve degeneration and regeneration to the resulting abnormal behaviors. Fiber histograms based on axon diameter and grid morphometry were used to quantify the pathologic state of nerve fibers, activated phagocytic cells, vessels, and edema at the lesion site. Approximately 90% of the axons demonstrated Wallerianlike degeneration by 3 days post-SCN. At 14 days, small diameter axons significantly increased in number from earlier times following SCN (P < 0.05) but were not significantly different from normal values. At 21 days, the number of small diameter axons was significantly increased over both 14 days (P < 0.05) and normal values (P < 0.05). At 28 days, intermediate diameter axons significantly increased in number with respect to all earlier time periods (P < 0.05). These increases in regenerating fibers overlapped with the development of peak autotomy at 7-14 days and the onset of allodynia after 21 days. Autotomy scores at 7 days positively correlated with grid morphometry data of regenerating axons (p = 0.7) and activated macrophages and Schwann cells (p = 0.8) and inversely correlated with edema (p= -0.8) using Spearman's rank correlation analysis. These data suggest a macrophage and Schwann cell involvement in the sensitization of first- and second-order neurons to afferent input which leads to neuropathic behaviors. These results are discussed in the context of a hypothesis for the generation of differential neuropathic behaviors associated with the pathological events of degeneration and regeneration following the chronic constriction injury model of neuropathic pain and SNC.     

Recovery of C-Fiber-Induced Extravasation Following Peripheral Nerve Injury in the Rat

Peripheral nerve injury leads to substantial alterations in injured sensory neurons. These include cell death, phenotypic modifications, and regeneration. Primary sensory neurons have recently been shown not to die until a time beyond 4 months following a nerve crush or ligation and this loss is, moreover, limited to cells with unmyelinated axons, the C-fibers. The late loss of C-fibers may be due to a lack of target reinnervation during the regenerative phase. In order to investigate this, we have used a particular peripheral function, unique to C-fibers, as a measure of peripheral reinnervation: an increase in capillary permeability on antidromic activation of C-fibers, i.e., neurogenic extravasation. This was investigated in rats that had received a nerve crush injury 1 to 50 weeks earlier. Some recovery of the capacity of C-fibers to generate extravasation was detected at 8–10 weeks, which increased further at 12–14 weeks, and then plateaued at this level with no further recovery at 30 or 50 weeks. In intact and damaged sciatic nerves, Aβ-fibers never induced extravasation. These findings are compatible with the hypothesis that those C-fibers which make it back to their peripheral targets do not subsequently die and those that do not, may die.