黄芪多糖对红斑狼疮小鼠6种抗磷脂抗体的影响

目的 :观察黄芪多糖 (PG2 )对红斑狼疮小鼠抗心磷脂 (anticardiolipin ,aCL)、抗磷脂酰胆碱 (antiphosphatidylcho line ,aPC)、抗磷脂酰丝氨酸 (antiphosphatidylserine,aPS)、抗磷脂酰肌醇 (antiphosphatidylinositol,aPI)、抗磷脂酸 (antiphosphatidicacid ,aPA)和抗磷脂酰乙醇胺 (antiphosphatidylethanolamine ,aPE) 6种自身抗体的影响。方法 :19只雌性NZB×NZWF1小鼠随机分为黄芪I组 (2 5mg kg) 7只 ,黄芪II组 (5 0mg kg) 6只及生理盐水组 (0 2ml d) 6只 ,日一次腹腔注射 ;雌性BXSB及C5 7BL 6小鼠作对照 ,用酶联免疫吸附 (ELISA)法测定各组小鼠的 6种抗磷脂抗体A值进行比较。结果 :NZB×NZWF1小鼠黄芪II组各种抗磷脂抗体A均值比生理盐水组明显降低 (P <0 0 5或P <0 0 1) ,与BXSB ,C5 7BL 6小鼠比无统计学差异 ;黄芪I组与生理盐水组比有所升高 ;黄芪I组及生理盐水组与BXSB、C5 7BL 6比明显升高 (P <0 0 5或P <0 0 1)。结论 :黄芪多糖低剂量有使抗磷脂抗体升高的趋势 ,高剂量可明显抑制抗磷脂抗体的产生     

Inhibition of resistance to hemopoietic allo-grafts in granulocyte colony-stimulating factor transgenic mice

Transplanted allogeneic marrow cells often fail to engraft in a lethally irradiated host. This phenomenon, termed resistance to allogeneic marrow grafts or allo-resistance, is well documented, although its mechanism is not yet understood. Transplantation of major histocompatibility complex disparate allogeneic marrow cells into mice transgenic for granulocyte colony-stimulating factor (G-CSF) showed donor-derived spleen colonies (CFU-S) and resulted in stable allogeneic chimerism with excellent survival (100% up to 40 days and 89% up to 120 days). Under the same experimental conditions, all the littermate controls failed to show CFU-S and died shortly after marrow transplantation. Thus, resistance to allogeneic marrow cells appeared to be severely impaired in this transgenic mouse. The observation that neutralizing antibody against G-CSF restored allo-resistance in G-CSF transgenic mice and that CFU-S was inducible upon administration of recombinant G-CSF using a mini-osmotic pump in non-transgenic recipients, suggests that an elevated level of this cytokine is important for the inhibition of allo-resistance. Thus, G-CSF was found to play a role in allogeneic resistance to marrow grafts and the G-CSF-transgenic mice provide a useful model to study the inhibition of the resistance. The inhibition of allo-resistance may be useful in preparing allogeneic bone marrow chimeras in both experimental and clinical settings.     

Germinal center formation in mice lacking αβ T cells

T cells are essential for inducing clonal B cell expansion in germinal centers during T cell-dependent antibody responses. However, class-switched antibodies are readily detectable in TCRα-deficient mice that congenitally lack αβ T cells, including those such as IgG1 that are considered to be dependent on collaboration between B cells and αβ T cells. This observation suggests that a novel form of B:T collaboration may be evident in TCRα^?/? mice. We report that germinal centers develop spontaneously in mice lacking T cell receptor α genes (TCRα^?/?), despite the absence of αβ T cells. They are not seen in TCRβ^?/? mice kept in similar conditions. Both strains of mice have γδ T cells, but it is a subset of T cells expressing TCRβ and CD4 that is dominant in the germinal centers of TCRα^?/? mice. Exceptionally, germinal centers were associated with CD4⁺ γδ T cells. The expression of CD4 seems to be important, for few extrafollicular T cells have CD4 and CD4 is largely absent from TCRβ^?/? T cells. The CD4⁺ TCRβ cells may help B cells produce autoantibodies that have been identified in TCRα^?/? mice.     

Influence of glycosylphosphatidylinositol-linked H-2Dd molecules on target cell protection and natural killer cell specificity in transgenic mice

The expression of certain major histocompatibility complex (MHC) class I ligands on target cells is one important determinate of their susceptibility to lysis by natural killer (NK) cells. NK cells express receptor molecules that bind to MHC class I. Upon binding to their MHC class I ligand, the NK cell is presumed to receive a signal through its receptor that inhibits lysis. It is unclear what role the MHC class I molecules of the effector and target cells play in signaling to the NK cell. We have investigated the role of the cytoplasmic and transmembrane domains of MHC class I molecules by producing a glycosylphosphatidylinositol (GPI)-linked H-2D^d molecule. The GPI-linked H-2D^d molecule is recognized by H-2D^d-specific antibodies and cytotoxic T lymphocytes. Expression of the GPI-linked H-2D^d molecule on H-2^b tumor cells resulted in protection of the tumor cells after transplantation into D8 mice (H-2^b, H-2D^d) from rejection by NK cells. In addition, NK cells from mice expressing the GPI-linked H-2D^d molecule as a transgene were able to kill nontransgenic H-2^b lymphoblast target cells. The GPI-linked MHC class I molecule was able to alter NK cell specificity at the target and effector cell levels. Thus, the expression of the cytoplasmic and transmembrane domains of MHC class I molecules are not necessary for protection and alteration of NK cell specificity.     

Thymic Medulla Epithelial Cells Acquire Specific Markers by Post-Mitotic Maturation

The development of thymocyte subsets and of the thymic epithelium in SCID and RAG-2^-/– mice was monitored after normal bone-marrow-cell transfer. The kinetics of thymic reconstitution and their relationships with cell proliferation were investigated by using bromodeoxyuridine to detect DNA-synthesizing cells among lymphoid cells by 3-color flow cytometry, and in epithelial compartments by staining frozen sections. Thymocytes started to express CD8 and CD4 10 days after transfer, simultaneously with extensive proliferation. The first mature CD4⁺ single-positive cells were generated, from resting CD4⁺CD8⁺ cells after day 15. During this day 10–15 period, many epithelial cells positive for cortexspecific or panepithelial markers were labeled with BrdUrd after pulse-injection. Organized medullary epithelium also developed after day,15, that is, synchronously with the appearance of mature thymocytes, but medullary cells were never found BrdUrd⁺. These results suggest that, in these models, the reconstitution of the thymic epithelial network proceeds through expansion of preexisting cortical or undifferentiated cells and by later maturation (acquisition of specific markers) of medullary cells. This last process is dependent of the presence of mature thymocytes.     

Regional distribution of the 5-HT innervation in the brain of normal and lurcher mice as revealed by [H]citalopram quantitative autoradiography

The neurological cerebellar mutant lurcher is characterized by a primary degeneration of Purkinje cells as well as a retrograde secondary partial degeneration of cerebellar granule cells and inferior olivary neurons. Since serotonin (5-HT) has been implicated in the modulation of excitatory amino acid systems of the cerebellum, the 5-HT innervation of the normal and lurcher mice was examined by quantifying uptake sites using [³H]citalopram autoradiography, and by biochemical assays of the indoles 5-HT, 5-hydroxy- -tryptophan and 5-hydroxyindole-3-acetic acid using high-performance liquid chromatography. Comparable results were found between [³H]citalopram binding and 5-HT tissue concentrations in different brain regions. The highest [³H]citalopram labelling was observed in defined structures of the mesencephalic and upper pontine regions, in limbic structures, in hypothalamus and in discrete thalamic divisions, while the lowest labelling of uptake sites was documented in cerebellum and brainstem reticular formation. In lurcher mutants, the histology confirmed cell degeneration and the reduction in width, leading to 65%, 45% and 25% atrophies of total cerebellum, deep nuclei and inferior olivary nucleus, respectively. The [³H]citalopram labelling corrected for surface loss was 45% and 20% higher in cerebellar deep nuclei and red nucleus, respectively, but remained unchanged in the cerebellar cortex and inferior olivary nucleus. Moreover, higher labelling was found in nucleus raphe dorsalis, ventral tegmental area, inferior colliculus, locus coeruleus, pontine central grey and anterior thalamic nuclei, areas known to be part of cerebellar afferent and efferent systems. The present results indicate that in such pathological conditions as described for the lurcher mutant, the 5-HT system may modulate motor function not only at the level of the cerebellum, but also in other forebrain structures functionally related to the motor system.     

Histological Method for Evaluation of the Efficiency of Enerlit-Clima

We propose a method of evaluation of anticlimacteric efficiency of a drug by its effect on the estrous cycle. The study was carried out on 9-month-old mice with retained, but notably reduced reproductive function. Analysis of the cell components of the estrous cycle was carried out on histological preparations of vaginal smears.     

1-磷酸鞘氨醇对烧伤后血管通透性的作用研究

目的探讨1-磷酸鞘氨醇（sphingosine 1-phosphate，SIP）对小鼠烧伤后血管通透性的影响。方法BABL／c雄性小鼠，90℃（假烧伤组为37℃）水烫背部体表面积约30％致Ⅲ度烧伤后补液1ml，复制烧伤模型。实验分为6组：假烧伤组、假烧伤＋S1P组、假烧伤4-DMS组、烧伤组、S1P＋烧伤组、烧伤＋S1P组。连续观察小肠系膜微静脉烧伤后20～50min的荧光白蛋白渗出情况，用荧光密度比值Pa表示血管通透性，Pa越大通透性越高。结果假烧伤组4-DMS组Pa值在50min时为0．8160±0．0713，明显高于单纯假烧伤组（0．6575±0．1154，P〈0．05）。烧伤后血管通透性显著增加，S1P＋烧伤组Pa值自烧伤25min后明显低于烧伤组（P〈0．01），维持在正常水平，而烧伤＋S1P组Pa值与烧伤组比较无明显统计学差异。结论S1P对正常的内皮屏障功能具有保护作用。烧伤后血管通透洼显著增加，S1P能预防烧伤后血管通透性的增加，但对烧伤后已经升高的血管通透性没有明显治疗作用。     

The role of muscarinic receptor subtypes in acetylcholine release from urinary bladder obtained from muscarinic receptor knockout mouse

We investigated the subtype of prejunctional muscarinic receptors associated with inhibition of acetylcholine (ACh) released from the mouse bladder. We measured endogenous ACh release in the bladder obtained from the wild-type mice and muscarinic 1-5 (M1-M5) receptor knockout (KO) mice. Electrical field stimulation increased ACh release in all bladder preparations obtained from wild-type and M1-M5 receptor KO mice. The amount of ACh released from M1-M3 and M5 receptor KO mice was equal to that in the wild-type mice. In contrast, the amount of electrical field stimulation-induced ACh release in M4 receptor KO mice was significantly larger than that in the wild-type mice, but the extent of increase was small. Atropine increased electrical field stimulation-induced ACh release to levels found in wild-type mice in all M1-M5 receptor KO mice. In M2/M4 receptor double KO mice, the amount of electrical field stimulation-induced ACh release was equivalent to that in the M4 receptor KO mice. The cholinergic component of electrical field stimulation-induced contraction (in the presence of alpha,beta-methylene ATP) in the detrusor of M4 receptor KO mice was no different from that in the detrusor of wild-type mice. M4 receptor immunoreactivity was located between smooth muscle cells, colocalized with choline acetyltransferase immunoreactivity. These results indicate that the prejunctional inhibitory muscarinic receptors are of the M4 and non-M2 receptor subtypes. The nature of the non-M2 receptors remains unknown.     

Object recognition memory and BDNF expression are reduced in young TgCRND8 mice

The TgCRND8 mouse model of Alzheimer's disease exhibits progressive cortical and hippocampal β-amyloid accumulation, resulting in plaque pathology and spatial memory impairment by 3 months of age. We tested whether TgCRND8 cognitive function is disrupted prior to the appearance of macroscopic plaques in an object recognition task. We found profound deficits in 8-week-old mice. Animals this age were not impaired on the Morris water maze task. TgCRND8 and littermate controls did not differ in their duration of object exploration or optokinetic responses. Thus, visual and motor dysfunction did not confound the phenotype. Object memory deficits point to the frontal cortex and hippocampus as early targets of functional disruption. Indeed, we observed altered levels of brain-derived neurotrophic factor (BDNF) messenger ribonucleic acid (mRNA) in these brain regions of preplaque TgCRND8 mice. Our findings suggest that object recognition provides an early index of cognitive impairment associated with amyloid exposure and reduced brain-derived neurotrophic factor expression in the TgCRND8 mouse.