Dynamic observation on liver and spleen morphology and serum antibody levels in mice with Schistosoma japonicum infection after praziquantel treatment

Abstract

Objective To investigate the dynamic morphology changes of liver and spleen,as well as soluble egg antigen (SEA)specific IgG antibodies in mice with S.japonicum infection after treatment by praziquantel.Methods 60 BALB/c mice were randomly divided into three groups,including infection,treatment and negative control groups. The infection and treatment mice were infected with S.japonicum cercaria on the abdomen.6 weeks post infection,mice in treatment group were given praziquantel for 4 consecutive days at dose of 150 mg/kg,and then were given praziquantel 3 consecutive days again at dose of 300 mg/kg at the 8 weeks post infection.4,12,20,30 weeks after treatment with praziquantel,four mice of each group were weighted and then sacrificed to take liver and spleen for observation of the morphology changes,meanwhile the liver index ( the ratio of liver weight over body weight of mice) and spleen index (the ratio of spleen weight over body weight of mice) were calculated respectively.SEA-specific IgG level was detected weekly by ELISA for serum in treatment group before treatment and 2-30 weeks after treatment.Experimental results were analyzed by GRAPHPAD PRISM 5.0 (GraphPad Software,San Diego,CA )statistical analysis software.Results Four weeks after treatment with praziquantel,the morphology of liver and spleen were significantly improved,and the spleen index of treatment group (0.01 1 ± 0.002) is reduced than infection group (0.022 ± 0.007).20 weeks after treatment,the spleen index(0.007 ± 0.001 ) return to levels of negative control group (0.005 + 0.002).12 weeks after treatment,SEA-specific IgG levels ( 1.327 ±0.189)in serum of treatment group,which were diluted 2000 times,significantly reduced than that before treatment( 1.850 ± 0.157 ).Conclusion Joint detection of morphology of liver and spleen and SEA-specific IgG levels can be used for preliminary evaluation of the therapeutic effect of praziquantel. Key words: Schistosoma japonicum; BALB/c mice; Praziquantel; Spleen index; Liver index; IgG antibody