弓形虫Prugniaud株感染小鼠后脑组织病理学动态观察

Observation for dynamic histopathology of brain in mice infected with Toxoplasma gondii Prugniaud strain

目的观察Prugniaud株弓形虫感染小鼠后脑的组织病理学动态变化及包囊的形成。方法弓形虫Prugniaud株10个包囊/只鼠（0.5mL）经腹腔感染40只ICR小鼠,对照组22只小鼠接种同等量的PBS,观察小鼠的发病情况,并于感染第5d、10d、15d、20d、25d、30d、60d、90d、120d、150d和180d剖杀小鼠,取脑组织制作切片,作HE染色和免疫组织化学检测,同时提取脑组织DNA,用PCR法扩增弓形虫B1基因特异性片段。结果经腹腔感染小鼠从第6d开始出现食欲减退、耸毛、怠惰、抖动、腹泻及死亡等临床症状,死亡率为15%,第20d后症状开始减轻。HE染色镜检在感染第5d未见明显病理变化,第10d起见明显的神经元变性、卫星现象及噬神经现象,第15d起见神经胶质结节及较小的弓形虫包囊,第20d起珠网膜下腔见炎症细胞浸润,第25d起见血管套现象,第90d时珠网膜下腔见肉芽组织,第120~180d观察到弓形虫包囊、神经胶质结节及珠网膜下腔少量炎症细胞浸润共存现象。免疫组织化学显示在感染第10d脑组织细胞胞浆和胞核中发现弓形虫抗原颗粒,以后随着包囊增多抗原开始逐渐减少。PCR法从感染第10d至180d小鼠脑组织中均检测到弓形虫B1基因特异性片段。结论弓形虫Prugniaud株感染小鼠后速殖子可在几天内侵入脑,但出现包囊的时间可晚至15d,该虫可导致小鼠脑组织细胞变性坏死和非特异性脑膜脑炎的病理改变。15d以后随包囊形成脑组织病变逐渐减轻,但包囊可存在于脑组织中达180d。

In order to observe the dynamic histopathology change of the mice brain and the cyst formation after the mice infected by Toxoplasma gondii Prugniaud strain.40 ICR mice were infected intraperitoneally with 10 cysts each（0.5mL）,and 22 mice were injectedby PBS partes aequales.Incidence of the mice was observed.The mice were killed and the brains were detected by using histopathology and immunohistochemistry.DNA was extracted of brain tissue,and then the special sequence of Toxoplasma gondii B1 gene was amptified by PCR at 5-day（5d）,10d,15d,20d,25d,30d,60d,90d,120d,150d and 180d post-infection.The results showed that the mice infected with the cysts began to fall ill at 6d post-infection,and to recover at 20d post-infection.Symptoms contained decreased food appetite,lofty fur,sloth,buffeting and diarrhea,and the mortality rate was 15 percent.Microscopic examination from HE staining didn＇t find obvious histopathology changes at 5d post-infection.Neuronal degeneration,satellitosis and neruonophagia were found since 10d post-infection.We found some neuroglial cell tubercle and a small Toxoplasma gondii cyst since 15d post-infection.Inflammatory cells infiltration could be seen on cavitas subarachnoidealis since 20d post-infection.Sleeve cuffing could be seen since 25d post-infection.Granulation tissue could be seen on cavitas subarachnoidealis at 90d post-infection.Cysts,neuroglial cell tubercle and lesser inflammatory cell infiltration on cavitas subarachnoidealis coexist from 120d to 180d post-infection.Toxoplasma gondii or Toxoplasma antigen particle could be seen in endochylema or nucleus of brain tissue since 10d post-infection by immunohistochemistry,and then cyst began to increase with decrease of antigen.Specificity sequence of Toxoplasma gondii B1 gene could be detected by PCR from 10 days to 180 days post infection.Those results indicated that tachyzoite of Toxoplasma gondii Prugniaud strain would invade the brain after several days post-infection,but the cyst would be found until 15 days post-infection.The strain could lead to some pathology changes,including degeneration and necrosis of brain cells,and non-specificity meningoencephalitis.It＇s suggested that Pathological changes would relieve gradually with the cyst formation after 15d post-infection,but the cyst would exist the brain until 180d post-infection.