兔脑炎原虫引起的脑组织细胞凋亡

为了调查兔脑炎原虫引起脑组织细胞的凋亡情况,本研究用特殊染色、TUNEL染色、凋亡蛋白免疫组化染色和Western blot,对40只家兔的脑组织进行了详细研究。结果表明,病兔的脑组织中均检出了肉芽肿和脑炎原虫。脑炎原虫所引起的脑细胞凋亡主要发生于脑血管的内皮细胞、星形胶质细胞、巨噬细胞和上皮样细胞,其次为病变所累及的神经细胞。用TUNEL的免疫酶-荧光染色和抗凋亡蛋白的免疫组化染色,凋亡细胞均呈强阳性反应,被染成棕褐色。对脑组织蛋白提取物进行Western blot检测,病兔脑组织中P~(53)、Bcl-2、Bax和c-Myc凋亡基因蛋白表达量明显高于对照兔,差异非常显著(P0.01)。结果表明,兔脑炎原虫在脑组织细胞内寄生时可以引起细胞凋亡。     

兔脑炎原虫引起肾上皮凋亡的研究

对 16只具有兔脑炎原虫病的示病症状 ,即出现不同程度的头颈歪邪、震颤、平衡失调和转圈运动等运动障碍症状的獭兔 ,运用原位末端标记技术和基因染色技术 ,着重对病兔肾组织损伤的发生进行了研究。结果表明 :肾远曲小管和集合管是脑炎原虫主要的寄生部位 ,在此常能检出虫体或假囊 ;凋亡的细胞多见于集合小管的上皮细胞。用TUNEL染色 ,不同阶段的凋亡细胞可出现不同的病理形态学变化。初期的凋亡细胞 ,其胞核浓缩 ,胞膜增厚 ,着色较均匀 ;后期的凋亡细胞 ,其胞核的体积明显变小 ,胞浆减少 ,胞膜呈皱襞状 ,紧紧地包绕着皱缩而浓染的细胞核 ,形成典型的凋亡小体。用 P53和 Bcl- 2染色 ,由于基因表达产物的扩散 ,不仅受损细胞的核染色较深 ,而且胞浆染色也较深。研究证明 ,TUNEL 染色是一种检测由脑炎原虫引起肾细胞凋亡的灵敏、可靠的方法 ;P53和 Bcl- 2基因参与了肾细胞的凋亡过程 ;临床上病兔多尿与脱水可能主要与肾远曲小管和集合管的上皮细胞凋亡有关。     

兔的脑炎原虫病与儿茶酚胺的关系

１引言微孢子虫是隶属于微孢子门的一类真性细胞内寄生原虫。脑炎原虫病是众所周知的兔和其它动物的微孢子虫病,其病原为家兔脑胞内原虫,其特征是肉芽肿性肾炎和脑炎。在急性期,病变主要表现在肺、肾、肝,但在慢性期,仅累及脑、肾和心脏。以前的试验性研究已经证实宿...     

兔脑炎原虫性脑肉芽肿的病理学发生及形态特点

为了研究兔脑炎原虫(EC)性脑肉芽肿的病理学发生及形态特点,通过特殊染色、TUNEL染色、anti-GFAP染色和anti-NGF染色对26只病兔和10只健康对照兔的脑组织进行了详细地观察与分析。结果显示,EC能侵入血管内皮细胞引起血管损伤,可被单核细胞吞噬但不被消灭,并随之进入脑组织,导致大量星状胶质细胞增生,包围脑炎原虫集落或带虫的巨噬细胞,从而形成肉芽肿。EC性肉芽肿主要有3种形态,即细胞性肉芽肿、增生性肉芽肿和坏死性肉芽肿。构成脑肉芽肿的主要细胞为上皮样细胞、小胶质细胞、星状胶质细胞及内皮细胞,而淋巴细胞较少。结论,EC可侵入血管内皮破坏血脑屏障或随单核细胞的浸润而进入脑组织;脑肉芽肿的形成限制了EC的扩散;3种形态的脑肉芽肿实际上是一个病理过程的不同发展阶段。     

兔脑炎原虫致脑细胞凋亡的信号转导通路的研究

为探讨兔脑炎原虫引起脑组织细胞凋亡的信号转导通路,本试验用普通染色、特殊染色、免疫组化染色和Western blot检测等方法,对40只病兔和10只对照兔的脑组织进行了研究。结果显示,病兔的脑组织中均检出了形态不一的肉芽肿和脑炎原虫。兔脑炎原虫可引起巨噬细胞和肉芽肿中的上皮样细胞表达TNF-α,anti-TNF-α抗体染色呈阳性反应。细胞凋亡信号转导通路的关键蛋白caspase-8和caspase-3在血管内皮细胞、星形胶质细胞和上皮样细胞中呈强阳性或阳性反应,被anti-caspase-8和anti-caspase-3抗体染成淡棕色或深棕色。对脑组织蛋白提取物进行Western blot检测,病兔脑组织中TNF-α,caspase-8和caspase-3的表达量明显高于对照兔,差异极显著(P0.01)。结果表明,兔脑炎原虫可刺激脑组织中的巨噬细胞和上皮样细胞产生大量TNF-α,后者与细胞膜上的TNFR结合,从而激活死亡受体通路,引起胞浆内的caspase家族发生级联反应,导致细胞凋亡。     

兔脑炎原虫病脑组织的病理形态学观察

兔患脑炎原虫病时脑组织的病损主要是特异性肉芽肿和非化脓性脑炎。肉芽肿有３种类型：即上皮细胞性、增生性和坏死性肉芽肿。非化脓性脑炎有局灶性和弥漫性之分。隐性感染病兔的肉芽肿主要位于脑白质，肉芽肿周围有局灶性非化性脑炎变化。有症状病兔的肉芽肿不仅存在于白质，而且累及灰质；非化脓性脑炎弥漫性发生。在脑血管的内皮细胞中发现假囊，小血管中有血栓形成；受累的神经细胞中发现有较多量的脑炎原虫。     

兔脑炎原虫的分离与鉴定

3只临床表现斜颈、麻痹和打滚的病兔,经病理组织学检查诊断为脑炎原虫病.取其脑组织制成乳剂,接种于兔肾细胞、Vero细胞、猫肾细胞和兔脉络丛细胞.用前3种细胞均分离出原虫.该虫体表现为多种形态,呈杆状、圆形或卵圆形;Gram染色呈阳性,Goodpasture氏染色呈红色.用20%H_2O_2处理虫体,在相差显微镜下见到虫体极丝的伸展.通过虫体的形态学、染色特征和极丝的突出实验,鉴定该虫体为脑炎原虫.兔肾细胞、Vero细胞和猫肾细胞的感染率分别为40%、40%和5%,而在兔脉络丛细胞原代培养物中未检查到虫体.     

屠宰兔脑炎原虫病的快速检验

脑炎原虫病是一种人畜共患的寄生虫病,其病原为小孢子虫目(Microsporidia)、微粒子虫科(Nosematae)的兔脑炎原虫(En-cephalitozoon Cuniculi)。病原侵害的主要靶器官为脑组织和肾脏。据报道脑炎原虫的感染范围较广,可使鼠、兔、犬、猫、猴、     

兔脑炎原虫的超微形态与发育

用电镜连续７代动态地观察了培养细胞中兔脑炎原虫的超微结构与发育状态。脑炎原虫含有细胞核，但无线粒体、内质网和高尔基复合体等细胞器，其表面有几根极丝。脑炎原虫在培养细胞中除二分裂增殖外，还有裂体增殖和配体增殖。由于脑炎原虫有３种增殖方式，故在光学显微镜下呈多形态结构。     

Immune response in mice infected by Encephalitozoon cuniculi and suppressed by dexamethasone

Several indicators of immune response were observed in immunocompetent mice of the ICR line and those suppressed by dexamethasone upon their experimental infection with the microsporidia of Encephalitozoon cuniculi. The mice were infected by one-shot intraperitoneal administration of 5 x 10(7) pathogenic spores. On Days 7, 14, 28 and 42 after infection, peripheral blood leukocyte phagocytic activity was determined and compared, including phagocytic index and the blastogenic response in spleen cells to mitogenic activation by concanavalin A and phytohaemagglutinin. The results point to the fact that E. cuniculi itself can cause a significant decrease in phagocytic activity of phagocytic leukocytes in the early stages of infection as well as a remarkable decrease in the proliferative response of spleen cells to T-cellular mitogens.     

脑炎微孢子虫属3种微孢子虫的虫株未能感染食用动物

研究了脑炎微孢子虫属最常见的3种微孢子虫的虫株对于食用动物包括猪,牛,鸡,和火鸡的感染力.动物经口接种孢子后用2种方法来检测是否被感染,一种方法是在每日粪样中检测孢子,另一种方法是在动物接种21d后的器官组织学检查.尽管每种虫种的接种量高迭2×10~6至2×10~7个孢子,但是在每种动物都没有检测到感染.结果表明,本试验中所用的脑炎微孢子虫属的3种微孢子虫虫株缺乏对猪,牛,鸠和火鸡的感染力.     

Prevention and treatment of Encephalitozoon cuniculi infection in rabbits with fenbendazole

The efficacy of fenbendazole for preventing an experimental infection of Encephalitozoon cuniculi and for eliminating the spores from the central nervous system of naturally infected rabbits was investigated. Fenbendazole (20 mg/kg bodyweight daily) was administered from seven days before until two or 21 days after rabbits had been infected orally with 10(6) spores of E. cuniculi. Both regimens were effective in preventing the establishment of the parasites, as demonstrated by negative parasitic-specific serology and by the failure to isolate the parasite from brain tissue. In naturally infected, seropositive rabbits, parasites were successfully isolated from seven of nine untreated animals, but not from the brain tissue of eight animals treated with fenbendazole-medicated pellets for four weeks.     

Prevalence of antibodies to Encephalitozoon cuniculi in stray dogs as determined by an ELISA

An ELISA, using Encephalitozoon cuniculi spores as antigen, was used to determine the prevalence of specific anti-E cuniculi IgG in a group of stray dogs. In a preliminary survey 51 of 248 sera were classified as positive with titres of 1:400 to 1:3200. The 18 sera with titres of 1:400 were reclassified as negative when no IgG binding to the spores could be detected by comparison with a standard curve of anti-E cuniculi IgG. The remaining 33 sera (13.3 per cent) were classified as low, moderate or strong positives. Comparison of total IgG and specific IgG showed that specific IgG was greatly increased in the moderately and strongly positive sera. E cuniculi may be of importance as one cause of fading puppy syndrome when transmitted transplacentally, and as a complicating infection in human immunodeficiency diseases.