Wei Lin-lin, Cheng Yan-bin, Si Kai-wei, Gu Ning, Li Xiao-qi, Li Chen, Yuan Yu-kang
Department of Immunology and Pathogenic Biology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi. 2008 Dec 30;26(6):438-41.
To explore the effect of usnic acid on Toxoplasma gondii tachyzoites in vitro.
There are four groups named as (+)-usnic acid group, acetylspiramycin group, DMSO group and normal saline group. Groups of (+)-usnic acid and acetylspiramycin were further divided into 4 subgroups with final concentration of 5, 10, 25, 50 microg/ml respectively. Normal saline group and DMSO group were respectively given equal volume normal saline and 1% DMSO. Each group have 15 parallel tubes with 1 ml (1 x 10(6)/ml) T. gondii tachyzoites aqueous suspension. At 1 h, 2h and 4 h after drug treatment, tachyzoites were counted by light microscope with 0.4% Trypan blue staining. Tachyzoites in aqueous suspension was collected, and washed 3 times by PBS solution. Normal mice were inoculated intraperitoneally and observed for three generations. The cultivated rat cardiofibroblasts were then infected in vitro with T. gondii tachyzoites. At the same time, rat cardiomyocytes invasion by T. gondii tachyzoites was investigated.
At 4 h treated by 10, 25 and 50 microg/ml (+)-usnic acid, 100% T. gondii tachyzoites were stained. Some tachyzoites were swelling, blunt or round in the two ends; and granules appeared in the cytoplasm, the nuclei were deep stained. The changes of tachyzoites in acetylspiramycin group were similar to (+)-usnic acid group, 100% T. gondii tachyzoites were stained in 50 microg/ml acetylspiramycin subgroup. In inoculation tests, mice died at 8th to 9th days in 5 microg/ml (+)-usnic acid subgroup and numerous tachyzoites were detected in ascites. However, most mice survived to be killed in the other (+)-usnic acid subgroups and the tachyzoites were not found in ascites. All mice in acetylespirmycin groups died at 6th to 8th days after inoculation and many tachyzoites or pseudocysts were observed in mice ascites. In infecting cell tests, the cultivated rat cardiofibroblasts were infected in vitro by the tachyzoites after treated with 5 microg/ml (+)-usnic acid for 4 h, and pseudocysts were formed in infected cells. It was negative in the other subgroups of (+)-usnic acid. But the cultivated rat cardiofibroblasts were infected to varying degree in acetylspiramycin groups, normal saline group and DMSO group.
(+)-Usnic acid has a remarkable effect on T. gondii tachyzoites.
探讨松萝酸对体外培养的刚地弓形虫速殖子的作用。
分为（+）-松萝酸组、乙酰螺旋霉素组、二甲基亚砜（DMSO）组和生理盐水组。（+）-松萝酸组和乙酰螺旋霉素组再分别分为4个亚组，终浓度分别为5、10、25、50μg/ml。生理盐水组和DMSO组分别给予等体积的生理盐水和1% DMSO。每组设15支平行管，每管加入1 ml（1×10⁶/ml）刚地弓形虫速殖子悬液。药物处理后1 h、2 h和4 h，用0.4%台盼蓝染色，光学显微镜计数速殖子。收集悬液中的速殖子，用磷酸盐缓冲液（PBS）洗涤3次。正常小鼠腹腔接种，观察三代。然后用刚地弓形虫速殖子体外感染培养的大鼠心肌成纤维细胞。同时，研究刚地弓形虫速殖子对大鼠心肌细胞的侵袭情况。
10、25和50μg/ml（+）-松萝酸处理4 h后，100%的刚地弓形虫速殖子被染色。部分速殖子肿胀，两端钝圆或呈圆形；细胞质内出现颗粒，细胞核染色加深。乙酰螺旋霉素组速殖子的变化与（+）-松萝酸组相似，50μg/ml乙酰螺旋霉素亚组100%的刚地弓形虫速殖子被染色。接种试验中，5μg/ml（+）-松萝酸亚组小鼠于第8至9天死亡，腹水中检测到大量速殖子。然而，其他（+）-松萝酸亚组的大多数小鼠存活至处死，腹水中未发现速殖子。乙酰螺旋霉素组所有小鼠接种后第6至8天死亡，小鼠腹水中观察到许多速殖子或假包囊。在感染细胞试验中，5μg/ml（+）-松萝酸处理4 h后的速殖子可体外感染培养的大鼠心肌成纤维细胞，感染细胞内形成假包囊。（+）-松萝酸其他亚组为阴性。但乙酰螺旋霉素组、生理盐水组和DMSO组培养的大鼠心肌成纤维细胞均有不同程度的感染。
（+）-松萝酸对刚地弓形虫速殖子有显著作用。
