血吸虫对吡喹酮抗药性的研究 Ⅵ 吡喹酮对曼氏血吸虫吡喹酮抗性株和敏感株虫卵肉芽肿形成的影响

STUDIES ON RESISTANCE OF SCHISTOSOMA TO PRAZIQUANTEL Ⅵ. EFFECT ON FORMATION OF EGG-GRANULOMAS IN LIVERS OF PRAZIQUANTEL RESISTANT AND SUSCEPTIBLE SCHISTOSOMA MANSONl TREATED IN VIVO

目的 体内比较吡喹酮对曼氏血吸虫吡喹酮抗性株与敏感株肝脏虫卵肉芽肿形成的影响。方法 用抗性株与敏感株尾蚴感染小鼠,在感染第58、59、60天每日以200 mg/kg微粒化吡喹酮悬液灌胃治疗小鼠,治后35 d剖杀小鼠取肝脏做石蜡切片,进行HE染色,显微镜下作病理学观察;以图像分析仪定量测定虫卵肉芽肿的面积。结果 敏感株未治疗组虫卵肉芽肿由大量炎性浸润细胞及少量间质成纤维细胞组成;治疗组则由少量炎性浸润细胞和大量间质成纤维细胞组成;未治疗组肉芽肿的面积明显大于治疗组,两者间差异具有非常显著性。但抗性株治疗组和未治疗组虫卵肉芽肿均由大量炎性浸润细胞和少量间质成纤维细胞组成,两组虫卵肉芽肿的面积间差异无显著性。结论 鼠体内吡喹酮的治疗对曼氏血吸虫吡喹酮敏感株和抗性株肝脏虫卵肉芽肿的形成影响作用具有显著差异;在肝组织中,敏感株虫卵对吡喹酮的敏感性高于抗性株。

Objective To compare the effect of praziquantel on the formation of egg-granulomas in the livers of Schistosoma mansoni worms between praziquantel-resistant and -susceptible parasite isolates in vivo. Methods Two praziquantel-resistant isolates and three praziquantel-susceptible isolates of S. mansoni were used to infect mice with cercariae respectively. On the day 58, 59 and 60 post-infection, the mice were treated with 200 mg/(kg·d) micronized praziquantel by oral gav-age. On day 35 post-treatment the mice were sacrificed and livers were examined pathologically. Liver samples were fixed, embedded in paraffin, cut in sections and stained with haematoxylin and eosin for microscopic observation. The areas of egg-granulomas were measured by using an analytical measuring system. Results Most of granulomas in the livers of mice infected with the susceptible isolates consisted of numerous infiltrating inflammatory cells and a small number of mesenchy-mal fibroblasts in untreated control groups, but most of egg-granulomas consisted of a small number of infiltrating inflammatory cells and mesenchymal fibroblasts in treated groups. The size of egg-granulomas in the liver of untreated groups was larger than that in treated groups. Most of the egg-granulomas in the liver of mice infected with resistant isolates in both untreated and treated groups consisted of numerous infiltrating inflammatory cells and mesenchymal fibroblasts. There were no differences between untreated and treated groups with respect to the size of egg-granulomas in the livers. Conclusion There were significant differences in the effect of praziquantel on the formation of egg-granulomas in the livers of Schistosoma mansoni worms between praziquantel-resistant and -susceptible parasite isolates in vivo. The eggs from susceptible control isolates were more sensitive to praziquantel than those from resistant isolates in the livers.