Fas系统参与介导烧伤后心肌细胞凋亡及牛磺酸的影响

目的观察Fas系统在烧伤后心肌细胞凋亡中的作用及牛磺酸的影响。方法选健康Wistar大鼠,随机分成对照组(Sham)、烧伤组(造成40%TBSAⅢ度烧伤)和牛磺酸保护组(烫伤后即刻腹腔注射牛磺酸400 mg/kg)。用原位末端标记(TUNEL)法检测凋亡细胞,RT-PCR检测Fas mRNA表达,免疫组化检测Fas/FasL和Caspase-8/3蛋白表达和荧光法分析Caspase-3活性。结果烧伤组大鼠伤后6 h和24 h心肌细胞凋亡指数分别为8.96±2.10和18.67±2.48,较对照组(0.92±0.34)有显著性升高,Fas蛋白阳性表达指数分别为13.51±1.56和14.55±1.89,也显著性高于对照组(2.46±0.75);Caspase-3活性分别为1.38±0.16和1.96±0.71,较对照组(0.35±0.06)有显著性差异。烧伤组凋亡指数与Fas表达之间有良好的相关性(r=0.86)。牛磺酸保护组细胞凋亡指数为2.14±0.68,Fas蛋白表达为3.71±0.82,Fas mRNA表达为0.17±0.03,Caspase-3活性为0.88±0.16,较烧伤组均有显著性降低。结论Fas系统参与了介导烧伤后心肌细胞凋亡,牛磺酸对烧伤后心肌细胞Fas表达及其信号转导有较好的拮抗作用。     

牛磺酸对实验性高血压大鼠脑脊液和血浆内皮素含量的影响

目的探讨牛磺酸对实验性高血压大鼠脑脊液、血浆内皮素-1(ET-1)含量的影响.方法Wistar大鼠36只,随机分为高血压组,牛磺酸组和对照组3组,高血压组和牛磺酸组建立大鼠主动脉狭窄-高盐摄入性高血压模型,牛磺酸组饲料中加牛磺酸,观察3组大鼠脑脊液、血浆ET-1含量及血压的变化,测定脑组织和主动脉组织牛磺酸含量及主动脉肌条的舒缩功能.结果应用牛磺酸后,高血压大鼠pMA,脑脊液和血浆ET-1水平均下降(P<0.05),血管舒缩功能得以改善.结论牛磺酸可降低脑脊液、血浆ET-1水平,从而降低血压.     

Immunocytochemistry of Amino-Acids in the Rodent Pituitary Using Extremely Specific, Very High Titre Antisera

The compartmental interrelationships of the metabolically related amino-acids glutamate, GABA and glutamine and the metabolically unrelated amino-acids taurine and glycine in the rodent pituitary, were investigated by light microscopic immunocytochemistry using highly specific antisera. Glutamate-like immunoreactivity was abundant in astrocytes in the posterior pituitary. Glutamine immunoreactivity was present only at low levels in the posterior pituitary, but was abundant in astrocytes within the intermediate lobe. Other glia-like ceils in the anterior pituitary were also glutamine-immunoreactive. GABA immunoreactivity was abundant in the intermediate lobe but absent from anterior and posterior lobes. The GABA immunoreactivity mainly took the form of small punctata, the majority of which were in intimate apposition to the glutamine-immunoreactive glia. Strong taurine immunoreactivity was present in astrocytes in the posterior pituitary but only weak labelling was present in intermediate and anterior lobes of the pituitary. Specific glycine immunoreactivity was not detected in the pituitary. These results suggest that glutamate-immunoreactive astrocytes in the posterior pituitary, unlike glia in loci such as the retina, do not convert much, if any, of their glutamate content into glutamine (or if they do, it is rapidly further metabolized to another compound), whereas those astrocytes in the intermediate lobe do contain glutamine. The spatial association of GABAergic fibres with glutamine-positive astrocytes raises the possibility that astrocytes in the intermediate lobe receive a GABAergic innervation. Glutamate, glutamine and taurine (or their metabolites) may have roles as neuroactive substances regulating pituitary secretion.     

Differential effect of taurine and serotonin on the outgrowth from explants or isolated cells of the retina

The sulfur amino acid taurine and the indoleamine serotonin increases and decreases, respectively, the outgrowth from goldfish retinal explants. Taurine seems to be acting, at least partially, through an increase in calcium fluxes, and the serotonin-inhibiting effect appears to be mediated by serotonin_1A receptors and cAMP. Isolated cells of postcrush goldfish retina and of retina from 5-day-old rats were cultured in the presence of taurine or serotonin. In the goldfish, the classical morphology of postcrush ganglion cells was observed. An antibody against the glycoprotein Thy-1 labelled three types of cells in the cultures of goldfish retina. The number of cells outgrowing and the length of the main neurite was measured at 5 days in culture in both species. The number of cells presenting neurites was increased in the goldfish retina by the addition of taurine, and decreased by serotonin. However, the length of the neurites was unaffected by the addition of the modulators. In the rat, only a slight decrease in the number of cells outgrowing was observed in the presence of serotonin. The incorporation of [³H]thymidinewas not modified after 5 days in culture in the presence of taurine or serotonin, either in the goldfish or in the rat retina. The antibody Thy 1.1 can label retinal cells of the goldfish invitro, one of them being ganglion cells. The trophic effect exerted by taurine in the postcrush goldfish retina needs the integrity of the tissue favoring the interaction of cells and factors, because outgrowth increases in retinal explants, but not in isolated cells.     

牛磺酸与大脑发育关系的初步探讨——牛磺酸与行为

本实验将断乳大鼠随机分成三组。补充0.6％牛磺酸组(ST组);未补充牛磺酸组(TF组);及5703大鼠常备膳组(5703组)。用水迷宫及食物偏爱性试验观察补充牛磺酸对大鼠学习、记忆能力的影响。结果表明,三组大鼠在水迷宫试验总潜伏期,总错误次数,无误率及持续时间四项指标上均存在高度显著差异。ST:TF P<0.01;ST:5703 P<0.01;5703:TF P<0.05。ST与TF在食物偏爱性试验上存在显著差异(P<0.05)。上述结果表明:牛磺酸与大脑发育有关,表现为补充了牛磺酸的大鼠在学习、记忆等方面的提高。而牛磺酸缺乏对幼鼠大脑及智力发育有不利影响,表现为学习、记忆能力的不足。     

急性分离的大鼠骶髓后连合核神经元由抑制性氨基酸诱导的电流反应(英文)

应用制霉菌素穿孔全细胞电压钳技术．在急性分离的大鼠骶髓后连合核（SDCN）神经元上，研究抑制性氨基酸诱导的反应的电生理学和药理学特性。当钳制电压为-40mV时，γ-氨基丁酸（GABA）、甘氨酸（Gly）和牛磺酸（Tau）均诱导产生内向电流。它们的EC50值分别是GABA5．2×10-5M，Gly4．0×10-5M及Tau1．6×10-4M。其Hill系数分别为GABA1．21，Gly1．27和Tau1．23。所有这些电流均在膜电位为-1．8mV左右时翻转。此外．Tau和Gly反应问还存在很强的交叉脱敏。结果提示，GABAA，Gly和Tau作为递质，通过受体Cl-通道复合体．在调节SDCN社经元伤害性传递中可能有重要作用。     

gamma-Aminobutyric acid and taurine release in the striatum of the rat during hypoglycemic coma, studied by microdialysis

Extracellular levels of striatal gamma-aminobutyric acid (GABA) and taurine were monitored during insulin-induced hypoglycemia using microdialysis. At the onset of isoelectricity in the electroencephalogram (EEG), a transient 5-fold increase in the levels of GABA occurred. Taurine levels increased 5 min following the onset of isoelectricity and continued to increase during the entire isoelectric period. The results demonstrate that events associated with the onset of isoelectricity during hypoglycemia trigger an increase in extracellular concentrations of GABA and taurine. The discrepancy in time-course of these changes may reflect differences in compartmentation, function and metabolism of the two amino acids.     

牛磺酸治疗通过激活自噬介导对老年大鼠骨量和骨强度的保护作用

目的探讨牛磺酸(NHS)对老年大鼠骨量流失的影响,并探讨可能的机制。方法将30只大鼠随机分为对照组(CON)、模型组(MOD)以及牛磺酸组(NHS),每组10只;其中NHS组大鼠每天接受牛磺酸(2 g/kg)治疗12周;待治疗结束后通过Micro-CT检测、HE染色切片、血清指标、蛋白质印迹观察治疗效果,探讨可能的机制。结果治疗12周后,与MOD组相比,三点弯曲试验、Micro-CT和HE染色切片结果显示NHS组大鼠的骨小梁数量、骨强度和骨密度(bone mineral density,BMD)得到明显改善。NHS组大鼠最大载荷和弹性模量、BMD、TV/BV、Tb.N、Tb.Th和Tb.Sp较OVX组明显改善(P<0.05)。和MOD组比较,NHS治疗后大鼠血清BLAP、P1NP、TRACP-5b和β-CTX水平明显降低,组间差异有统计学意义(P<0.05)。和MOD组比较,NHS组Runx2、BMP2、Beclin-1和LC3Ⅱ/LC3-Ⅰ表达水平明显上调,而P62表达水平显著下调,比较差异有统计学意义(P<0.05)。结论NHS可能通过激活自噬,从而对年龄引起的骨量丢失起到保护作用。     

牛磺酸对大鼠心脏模拟缺血再灌注损伤的保护作用

在离体大鼠心脏模拟缺血再灌注(I/R)损伤的模型上观察了牛磺酸的心肌保护作用。实验结果发现预先给大鼠牛磺酸灌胃(300mg/kg)三日或再灌注同时给药(20mmol/L),对心肌均有保护作用,明显减少心肌细胞内的Mb、LDH的漏出,降低心肌MDA的生成,减轻细胞内钙的聚集,促进心肌ATP含量的恢复。在本实验条件下预防应用牛磺酸较再灌注的同时应用更为有效,表现为更大程度地减少LDH漏出,抑制心肌MDA生成和钙聚集。结果证明牛磺酸具有心肌保护作用,对于防治心肌I/R损伤可能具有临床应用价值。     

牛磺酸对大鼠生长和智力发育的影响

1目的　探讨牛磺酸对大鼠生长及智力发育的影响。2方法　 Wistar大鼠自受孕开始分别喂以不同的饲料 :基础饲料 (A组 ) ,基础饲料添加牛磺酸 (B组 ) ,低蛋白饲料 (C组 ) ,低蛋白饲料添加牛磺酸 (D组 )。断乳后的仔鼠仍继续按原饲料分别喂养并检测体质量、观察体态及辨别学习能力。3结果　 A,B,D组出生 16 d,平均体质量无显著差异 ;至 44 d,D组平均体质量明显低于 A,B组 (F =381.83,q=18.87,18.45 ,P<0 .0 1) ,C组则出现明显营养不良 ,体质量低于 D组 (q=2 1.41,P<0 .0 1)。到 6 0 d时 ,A ,B组体质量均已达到 15 0 g左右 ,而 D组的大鼠仅为80 g左右。A组大鼠亮度辨别学习实验的达标时间为 (4.70± 0 .94) d,B组大鼠达标时间为 (3.5 4± 0 .75 ) d,两者具有显著差异 (t=2 .2 5 ,P<0 .0 5 )。4结论　营养不良的情况下 ,自胚胎期开始补充牛磺酸 ,仍有助于仔鼠的生长发育 ,对智力发育也具有明显的促进作用。