Abstract: Objective To detect the molecular characterization of polysaccharide purified from Amusium pleuronectes， so as to investigate its role of intervention to the formation of hepatic fibrosis caused by Schistosoma japonicum infection. Methods The crude polysaccharide from A. pleuronectes was extracted and further purified， and the molecular weight and monosaccharide composition were determined by the high pressure size exclusion chromatography and PMP pre?column derivatization method， respectively. A total of 50 female BALB/c mice were randomly divided into five groups： A （normal group）， B （experimental group）， C （polysaccharide group）， D （praziquantel）， and E （polysaccharide + praziquantel group）. The mice in B， C， D， or E groups were attacked on the abdominal skin by using the cercariae of S. japonicum （30 ± 2 for each mouse） respectively. After 8 weeks， the mice in C， D， and E groups were administrated by polysaccharide and/or praziquantel， and the mice in B group were instead of saline. All the livers and sera were collected after 16 weeks. HE staining was employed for the livers， and serum IFN?γ and IL?13 were measured by using ELISA kits. Results The molecular weight of purified polysaccharide from A. pleuronectes was 11.7 kDa. Compared with A and B groups， the serum levels of IFN?γ in C， D， and E groups were significantly increased （F = 63.525， P < 0.01）. However， the serum levels of IL?13 in C， D， and E groups were significantly decreased （F = 99.788， P < 0.01） compared with that in B group. HE staining showed that the egg nodules and hepatic fibrosis were observed in B， C， D， and E groups. The number of egg nodules and fibrosis degree in E group were milder than those in B group （c2 = 7.875， P < 0.05）. Conclusions The polysaccharide from A. pleuronectes has an obvious effect in preventing hepatic fibrosis process induced by S. japonicum infection， particularly combining with the administration of praziquantel.

Key words: Amusium pleuronectes； Polysaccharide； Schistosoma japonicum； Liver fibrosis； Praziquantel； Mouse

摘要： 目的 检测亚洲日月蛤多糖的分子特性，探讨其在干预小鼠日本血吸虫肝纤维化中的作用。方法 提取并纯化亚洲日月蛤多糖，采用凝胶排阻法对其分子量进行测定，应用PMP柱前衍生法对其单糖组成进行检测。取50只雌性BALB/c小鼠，随机分成5组，每组10只小鼠。A组给予生理盐水灌胃，B、C、D、E组小鼠分别经腹部皮肤攻击感染血吸虫尾蚴（30 ± 2）条/只；饲养第8周末，C、D、E组小鼠分别给予多糖、吡喹酮及多糖 + 吡喹酮治疗，B组小鼠给予生理盐水；第16周末，收集小鼠肝脏及血清，通过HE染色观察小鼠肝脏虫卵肉芽肿病变及肝纤维化情况，采用ELISA法检测血清IFN?γ、IL?13水平。结果 亚洲日月蛤多糖相对分子量为11.7 kDa，其多糖主要由葡萄糖组成。C、D组和E组小鼠血清IFN?γ浓度显著高于对照组（F = 63.525，P < 0.01），C、D组和E组小鼠血清IL?13浓度显著低于B组（F = 99.788，P < 0.01）。HE染色显示，B、C、D、E组小鼠肝组织均见不同程度虫卵结节和纤维化改变，A组小鼠肝脏正常，E组虫卵结节较B组少（c2 = 7.875，P < 0.05）。结论 亚洲日月蛤多糖具有明显的抗日本血吸虫肝纤维化作用，与吡喹酮联用效果更好。

关键词: 亚洲日月蛤；多糖；日本血吸虫；肝纤维化；吡喹酮；小鼠