阿魏酸对创伤性脑损伤小鼠的神经保护作用

目的本研究利用创伤性脑损伤(traumatic brain injury,TBI)小鼠模型观察阿魏酸(FA)对TBI的神经保护作用,为防治TBI继发性损伤的药物开发提供新思路。方法利用C57/BL6小鼠采用小鼠重复轻度脑损伤模型进行造模。通过干湿重比值法检测脑组织水肿、水迷宫实验检测小鼠学习记忆能力、HE染色法观察小鼠脑组织形态学变化、采用免疫组化法检测小胶质细胞的激活情况。结果与TBI组小鼠比较,阿魏酸组小鼠:脑含水量明显降低(P<0.05),Morris水迷宫实验中逃避潜伏期较TBI模型组明显缩短,原象限停留时间明显延长,活化的小胶质细胞减少。结论阿魏酸可改善TBI小鼠的空间学习记忆能力,降低TBI小鼠脑含水量,改善TBI小鼠的脑组织形态学变化,其机制与阿魏酸抑制小胶质细胞活化有关。     

Evidence for motility and pinocytosis in ramified microglia in tissue culture

Ramified microglial cells were investigated in primary cultures of dissociated cerebral cortical tissue from rats. The identification of these cells was confirmed through immunohistochemical staining with 7 monoclonal antibodies selective for microglia. While there was significant variation in staining intensity with different antibodies, all stained the identified ramified cells; the antibodies OX-42 and ED1 yielded the most intense immunoreactivity. Based on distinctive morphological features, the microglia could be identified in living cultures where they were monitored using time-lapse video recording. This technique revealed extremely dynamic features of cellular plasticity and motility. Ramified microglia exhibited constant and rapid alterations in the size and shape of their cell body with an associated extension and retraction of processes; concomitantly, the cells moved about in a circumscribed area. These features of plasticity and motility were unique to this cell type, and correlated with OX-42 immunostaining. The microglia also possessed a differentially high level of pinocytotic activity; this too was correlated with OX-42 staining. From the nature of their morphological plasticity and motility, high pinocytosis, and cellular distribution, it is hypothesized that the ramified microglia specifically function as a system of fluid cleansing in normal brain tissue.     

Imaging of activated microglia with PET and [11C]PK 11195 in corticobasal degeneration.

Positron emission tomography (PET) using [(11)C]PK 11195, a ligand for peripheral benzodiazepine receptor binding sites, offers the opportunity to image activated microglia in vivo. This tool may therefore be used to display the occurrence of microglial activation in the course of neurodegeneration. A patient with the clinical diagnosis of corticobasal degeneration (CBD) and left-sided symptoms was studied using fluorodeoxyglucose (FDG) and [(11)C]PK 11195 PET. We found a marked right hemispheric hypometabolism and asymmetric microglial activation in corresponding areas of the basal ganglia and right temporal and parietal cortex. [(11)C]PK 11195 PET suggests involvement of microglial activation in the pathogenesis of CBD.     

The effects of maternal inflammation on neuronal development: possible mechanisms

That maternal inflammation adversely affects fetal brain development is well established. Less well understood are the mechanisms that account for neurodevelopmental disorders arising from maternal inflammation. This review seeks to begin an examination of possible sites and mechanisms of action whereby inflammatory cytokines - produced by the mother or by the fetal brain - could impact the developing fetus. We focus first on the placenta where cytokines maintain the immunological environment that prevents maternal rejection of the fetus. Following a brief examination of placental transfer of maternal cytokines, the focus turns on embryonic microglia, early and ubiquitous residents of the developing brain. Finally, a more intense examination of interleukin-6 (IL-6) and bone morphogenetic proteins (BMPs) provides examples of glial- or maternal-derived cytokines that are known to have profound effects on developing systems and that could, if dysregulated, have undesirable consequences for brain development.     

Characterization of ramified microglia in tissue culture: pinocytosis and motility

Functional properties of ramified microglia were investigated in primary cultures of rat cerebral cortical cells. These microglia could be readily identified in both fixed and living cultures through previously established features. Based on their destruction by 5 mM L-leucine methyl ester, a high level of intrinsic endocytotic activity was established. When cultures were incubated with fluorescent latex beads to assess phagocytosis, little or no such activity was exhibited by ramified cells. However, when cultures were incubated with dyes or other soluble tracer compounds, these cells always exhibited labeling. This labeling was selective for ramified microglia in the cultures and was demonstrated using a variety of compounds, including trypan blue, lucifer yellow, horseradish peroxidase (HRP), and India ink. Intracellular label could be observed in vesicular structures; this localization corresponded to an active cellular process. Also, cellular labeling was inhibited by the presence of colchicine. These features supported the inference that the labeling was attributable to pinocytosis, and this process appeared to account for the vast majority of endocytotic activity in the ramified microglia. Possible physiological significance of this pinocytotic activity was indicated by the accumulation of various neurotransmitters/modulators: gamma-aminobutyric acid and vasoactive intestinal polypeptide (VIP). Ramified cells in these cultures have been previously noted to exhibit a constant and rapid pattern of motility, which was consistently observed here through time-lapse video recording; pinocytosis and rapid motility were shown to concur in individual cells. Based on their high intrinsic pinocytotic activity and pattern of cellular motility, the ramified microglia specifically are suggested to serve a constitutive function of fluid cleansing within the interstitial spaces of brain tissue.     

Axotomy of the rat facial nerve leads to increased CR3 complement receptor expression by activated microglial cells

Axotomy of the rat facial nerve leads to mitotic divisions of microglial cells without developing into phagocytes. In order to study the functional characteristics of those activated, i.e., proliferating but nonphagocytic, microglia we investigated the expression of monocyte/macrophage antigens by these cells. Our results show that activated microglia lack monocyte/macrophage antigens recognized by the monoclonal antibodies Ox-41, ED1, ED2, and Ki-M2R but express high levels of CR3 complement receptors in situ.     

Feline Immunodeficiency Virus Neuropathogenesis: From Cats to Calcium

Invasion of human immunodeficiency virus (HIV) into the central and peripheral nervous system produces a wide range of neurological symptoms, which continue to persist even with adequate therapeutic suppression of the systemic viremia. The development of therapies designed to prevent the neurological complications of HIV require a detailed understanding of the mechanisms of virus penetration into the nervous system, infection, and subsequent neuropathogenesis. These processes, however, are difficult to study in humans. The identification of animal lentiviruses similar to HIV has provided useful models of HIV infection that have greatly facilitated these efforts. This review summarizes contributions made from in vitro and in vivo studies on the infectious and pathological interactions of feline immunodeficiency virus (FIV) with the nervous system. In vivo studies on FIV have provided insights into the natural progression of CNS disease as well as the contribution of various risk factors. In vitro studies have contributed to our understanding of immune cell trafficking, CNS infection and neuropathogenesis. Together, these studies have made unique contributions to our understanding of (1) lentiviral interactions at the blood–cerebrospinal fluid (CSF) barrier within the choroid plexus, (2) early FIV invasion and pathogenesis in the brain, and (3) lentiviral effects on intracellular calcium deregulation and neuronal dysfunction. The ability to combine in vitro and in vivo studies on FIV offers enormous potential to explore neuropathogenic mechanisms and generate information necessary for the development of effective therapeutic interventions.     

Effect of curcumin on nitric oxide synthase expression in Iipopolysaccharide-activated microglia cells and the anti-oxidative effect of curcumin

BACKGROUND: It has been demonstrated that curcumin can increase the activities of various anti-oxidase in blood and tissue, effectively eliminate various free radicals, reduce the production of peroxisome, and alleviate oxidative stress reaction. Whether it has the same effect on microglia? OBJECTIVE: To observe the effects of curcumin on the expressions of inducible nitric oxide synthase (iNOS), nuclear factor-κB (NF-κB), and superoxide dismutase (SOD) in microglial cell line BV stimulated by lipopolysaccharide (LPS). DESIGN: An observational comparative study. SETTING: Research Room of Biochemistry, Medical College of Nantong University. MATERIALS: Mice microglia cell line BV, iNOS and NF-κB reporter gene plasmids were presented by Dr. Bhat.NR. from the Medical University of South Carolina (USA). Curcumin was produced by the Xi'an Branch of China Chengdu Scholar Bio-Tech. Co.,Ltd.; LPS (E.Coli O26:B6), anti-mice iNOS monoclonal antibody, horseradish peroxidase labeled goat-anti-mice IgG were the products of Sigma Company (USA). METHODS: The experiments were carried out in the Research Room of Biochemistry, Medical College of Nantong University from May 2006 to April 2007. ① Detection of iNOS: The cells were seeded onto 24-well plate at the density of 1×105, After the cells had adhered to the cover glasses, the cells were grouped as negative control group (the primary antibody was replaced by phosphate buffered solution PBS); normal control group (the cells were normally cultured); LPS-treated group (the cells were treated with LPS for 24 hours); curcumin+LPS group (the cells were treated with curcumin for 1 hour and LPS for 24 hours). The expressions of iNOS protein were detected with immunocytochemical staining. ② Determination of iNOS and NF-κB gene activities: According to the introduction of the kit for transfection, iNOS or NF-κB report gene plasmids were transiently transfected with LipofectamineTM2000 liposomes into the cells in the 24-well plate for 24 hours. The cells were divided into normal control group (the cells were normally cultured after transfected with report gene plasmids); blank plasmid group (the cells were normally cultured after transfected with blank plasmids); LPS-treated group (the cells were treated with LPS for 4 hours after transfected with report gene plasmids); curcumin+LPS group (the cells were treated with curcumin for 1 hour and LPS for 24 hours after transfected with report gene plasmids). The content of luciferase in the cell lysis buffer was determined after cell lysis. ③ Determination of SOD activity: The cells were seeded into culture bottle at the density of 1×106, and the divided into four groups, including normal control group (the cells were normally cultured); LPS-treated group (the cells were treated with LPS for 24 hours); curcumin+LPS group (the cells were treated with curcumin for 1 hour and LPS for 24 hours); vitamin C+LPS group (the cells were treated with vitamin C for 1 hour and LPS for 24 hours). The SOD activity was determined with xanthine oxidase and quantitative colorimetric assay. MAIN OUTCOME MEASURES: The expressions of iNOS protein, iNOS and NF-κB, and the activity of SOD were observed. RESULTS: ① Expression of iNOS protein in microglia: The expression of iNOS protein in the LPS-treated group was obviously higher than that in the negative control group (P < 0.01); Those in the curcumin+LPS group were significantly decreased as compared with that in the LPS-treated group (P < 0.01). ② Expressions of iNOS and NF-κB genes: The expressions of iNOS and NF-κB genes in the LPS-treated group were significantly higher than those in the normal control group (P < 0.01); Those in the curcumin+LPS group were significantly lower than those in the LPS-treated group (P < 0.01). ③ SOD activity: The activity of SOD in the LPS-treated group was significantly lower than those in the normal control group (P < 0.01). It in the curcumin+LPS group and vitamin C +LPS group was significantly higher than that in the LPS-treated group (P < 0.01). CONCLUSION: Curcumin could inhibit the expression of iNOS in the activated microglia, and it also has the abilities in eliminating free radicals and antagonizing lipid peroxidation.