早期运动训练对脑梗死后缺血半暗带GAP-43、Nogo-A及GFAP表达的影响*

目的： 探讨早期运动训练对脑梗死缺血半暗带区轴突生长相关蛋白43 （ GAP-43）、神经突起生长抑制因 子A（ Nogo-A）和神经胶质纤维酸性蛋白（ GFAP）表达的调控作用,及其对大鼠神经功能恢复的影响。方法 ： 健康成年雄性Wistar 大鼠,按随机数字表法分为假手术组、模型组、训练组。采用线栓法建立大脑中动脉闭塞 （ MCAO）大鼠模型,术后24 h 进行强度渐增的跑台运动训练14 d 和28 d。采用改良神经功能缺损评分（ mNSS） 评估神经功能;平衡木行走试验评估大鼠神经行为学改变;H-E 染色观察各组缺血半暗带区神经元病理形态学变 化;免疫印迹检测大鼠脑缺血半暗带GAP-43、Nogo-A 和GFAP蛋白表达变化;结果： 与假手术组相比,模型组 大鼠mNSS评分和平衡木试验评分均显著升高,脑缺血半暗带区GAP-43 和GFAP蛋白表达上调,而Nogo-A 的表 达下调。与模型组比较,跑台训练组大鼠mNSS评分与平衡木试验评分均显著降低,脑缺血半暗带区GAP-43 表 达上调,而Nogo-A 和GFAP表达下调。结论： 早期跑台训练可以促进轴突再生,抑制胶质瘢痕形成,最终改善 脑梗死大鼠神经功能障碍。     

血管紧张素Ⅱ对心肌细胞缝隙连接蛋白Cx43表达的时相性调控

目的研究血管紧张素Ⅱ(AngⅡ)诱导心肌细胞肥大后缝隙连接蛋白Cx43表达的变化规律和机制。方法分离培养大鼠心肌细胞后分为正常对照组、AngⅡ组和缬沙坦组,用Westernblot和免疫荧光法观察不同时间(12、24、48、72h)和不同浓度(1.0×10-9～1.0×10-5mol/L)下心肌细胞Cx43表达的变化,采用免疫荧光法检测3组心肌细胞24和72hCx43的表达。结果AngⅡ组心肌细胞较正常对照组明显肥大,蛋白含量增加。AngⅡ组心肌细胞在24～48hCx43表达上调,72h则明显下调,较正常对照组减少30%,而且在AngⅡ作用下呈浓度依赖性下调,24hAngⅡ组荧光阳性细胞数较正常对照组和缬沙坦组明显上调,72h则较其他组明显下调。缬沙坦可拮抗AngⅡ对Cx43表达的作用。结论AngⅡ诱导心肌细胞肥大过程中Cx43的表达出现一定时相性变化,并和AngⅡ呈明显的量效关系,提示AngⅡ可能通过AT1受体调控Cx43的表达而参与心肌细胞缝隙连接重构。     

Protein kinase Cε mediates salutary effects on electrical coupling induced by ischemic preconditioning

BACKGROUND: Ischemic preconditioning delays the onset of electrical uncoupling and prevents loss of the primary ventricular gap junction protein connexin 43 (Cx43) from gap junctions during subsequent ischemia. OBJECTIVE: To test the hypothesis that these effects are mediated by protein kinase C epsilon (PKCepsilon), we studied isolated Langendorff-perfused hearts from mice with homozygous germline deletion of PKCepsilon (PKCepsilon-KO). METHODS: Cx43 phosphorylation and distribution were measured by quantitative immunoblotting and confocal microscopy. Changes in electrical coupling were monitored using the 4-electrode technique to measure whole-tissue resistivity. RESULTS: The amount of Cx43 located in gap junctions, measured by confocal microscopy under basal conditions, was significantly greater in PKCepsilon-KO hearts compared with wild-type, but total Cx43 content measured by immunoblotting was not different. These unanticipated results indicate that PKCepsilon regulates subcellular distribution of Cx43 under normal conditions. Preconditioning prevented loss of Cx43 from gap junctions during ischemia in wild-type but not PKCepsilon-KO hearts. Specific activation of PKCepsilon, but not PKCdelta, also prevented ischemia-induced loss of Cx43 from gap junctions. Preconditioning delayed the onset of uncoupling in wild-type but hastened uncoupling in PKCepsilon-KO hearts. Cx43 phosphorylation at the PKC site Ser368 increased 5-fold after ischemia in wild-type hearts, and surprisingly, by nearly 10-fold in PKCepsilon-KO hearts. Preconditioning prevented phosphorylation of Cx43 in gap junction plaques at Ser368 in wild-type but not PKCepsilon-KO hearts. CONCLUSION: Taken together, these results indicate that PKCepsilon plays a critical role in preconditioning to preserve Cx43 signal in gap junctions and delay electrical uncoupling during ischemia.     

Sj43B基因编码蛋白的日本血吸虫虫体组织定位

目的确定Sj43B基因编码蛋白在日本血吸虫成虫体内组织及亚细胞水平定位。方法取新鲜日本血吸虫成虫标本,按电镜生物样品制备方法常规固定、包埋,制成超薄切片,与鼠源纯化的抗重组Sj43B基因编码蛋白的IgE抗体(对照组试验为正常鼠血清)反应,再与大鼠抗小鼠IgE的IgG抗体结合,最后与蛋白A-胶体金连接,透射电镜下观察胶体金颗粒的分布。结果用正常鼠血清处理虫体切片,从皮层、肌层到皮层细胞体,未见有明显的电子致密的胶体金颗粒分布。用特异性IgE抗体处理的样品上,胶体金颗粒分布较广泛,见于皮层、肌层、胞质、核膜和核质内。结论Sj43B基因编码蛋白在血吸虫成虫体内的分布无组织和亚细胞结构特异性。     

扶正化瘀胶囊对心肌梗死大鼠心肌缝隙连接蛋白43表达的影响

目的研究扶正化瘀胶囊对心肌梗死大鼠心肌缝隙连接蛋白43(connexin43,CX43)表达的影响。方法SD雄性大鼠随机分为假手术组、模型组以及扶正化瘀胶囊组和卡托普利组,每组各6只,采用结扎左冠状动脉前降支造成心肌梗死。术后10d开始灌胃给药,持续8周。用免疫组织化学方法观察心肌CX43表达的变化。结果在心肌梗死区域内,模型组与假手术组比较,CX43排列紊乱,阳性表达面积、平均光密度值和积分光密度均显著低于假手术组(P<0.01)。在梗死边缘区,扶正化瘀胶囊组CX43平均光密度值高于模型组(P<0.01),积分光密度高于模型组(P<0.05),CX43排列紊乱有所减轻,阳性表达面积与模型组无统计学意义。卡托普利组CX43平均光密度值高于模型组(P<0.01),积分光密度和阳性表达面积均高于模型组(P<0.05),CX43排列紊乱也有减轻。结论扶正化瘀胶囊能够部分改善心肌梗死大鼠心肌的CX43重构。     

Is synaptic loss a unique hallmark of Alzheimer's disease?

Synapses may represent a key nidus for dementia including Alzheimer's disease (AD) pathogenesis. Here we review published studies and present new ideas related to the question of the specificity of synapse loss in AD. Currently, AD is defined by the regional presence of neuritic plaques and neurofibrillary tangles in the brain. The severity of involvement by those pathological hallmarks tends to correlate both with antemortem cognitive status, and also with synapse loss in multiple brain areas. Recent studies from large autopsy series have led to a new standard of excellence with regard to clinical–pathological correlation and to improved comprehension of the numerous brain diseases of the elderly. These studies have provided evidence that it is the rule rather than the exception for brains of aged individuals to demonstrate pathologies (often multiple) other than AD plaques and tangles. For many of these comorbid pathologies, the extent of synapse loss is imperfectly understood but could be substantial. These findings indicate that synapse loss is probably not a hallmark specific to AD but rather a change common to many diseases associated with dementia.     

间隙连接蛋白43在舌黏膜癌变过程中的表达

目的 研究间隙连接蛋白43(connexin 43,Cx43)在口腔黏膜癌变过程中的表达变化,探寻其与口腔黏膜癌变的关系及意义.方法 用4亚基硝氧喹啉(4-nitroquinoline-1-oxide,4NQO)诱导SD大鼠口腔黏膜癌变,应用免疫组化方法检测Cx43在口腔黏膜癌变过程中各阶段的动态变化,分析Cx43与口腔黏膜癌变的关系.结果 Cx43蛋白主要表达于大鼠舌黏膜上皮细胞的胞膜、上皮基底层、棘层和颗粒层呈阳性染色,角质层未见表达.随着舌黏膜上皮异常增生程度的增加,Cx43的表达明显下降.在口腔鳞状细胞癌组织中,Cx43染色分布于癌细胞胞质以及鳞癌组织的角化珠内.Cx43在正常舌黏膜、轻度上皮异常增生、中度上皮异常增生、重度上皮异常增生、口腔鳞癌组织中阳性表达率分别为100.00％(10/10)、85.71％(12/14)、66.67％(8/12)、40.00％(4/10)、33.33％(4/12),差异有统计学意义(P＜0.05).结论 4NQO诱发舌黏膜癌变的过程中,Cx43蛋白表达水平随病变程度加重而显著下降,提示Cx43表达异常参与了口腔黏膜的癌变过程.Cx43表达下降是口腔黏膜癌变的早期事件.     

Maturational changes in connexin 43 expression in the seminiferous tubules may depend on thyroid hormone action

Introduction

Connexin 43 (Cx43) mediates the effect of thyroid hormone on Sertoli cell maturation in vitro. We investigated the influence of triiodothyronine (T3) administration on Cx43 expression in relation to the progress in seminiferous tubule maturation.

Material and methods

Male rats were daily injected with 100 µg T3/kg body weight from birth until postnatal day (pnd) 5 (transient treatment – tT3) or until pnd 15 (continuous treatment – cT3) or solvent – control (C). On pnd 16 serum hormone levels, body and testes weight, seminiferous tubule morphometry, Cx43 immunostaining and germ cell degeneration were investigated. Cx43 expression was also assessed in six 50-day-old adult untreated rats.

Result

tT3 increased 2.6-fold serum level of T3, testes weight, and seminiferous tubule diameter, and induced maturation-like dislocation of Cx43 expression from the apical to the peripheral region of Sertoli cell cytoplasm. In addition, incidence of Cx43-positive tubules declined from 86% in C to 46% after tT3, being similar to the adult value (30% of tubules Cx43-positive). In turn, cT3 increased serum T3 level 12-fold, and decreased body weight. Seminiferous tubules became shortened and distended, Sertoli cell cytoplasm vacuolated, Cx43 expression had minimal intensity and germ cell degeneration increased.

Conclusions

Cx43 might intermediate a short and transient stimulatory effect of T3 on seminiferous tubule maturation that disappeared together with exposure to the toxic effect of a continuously high level of the hormone.