In vitro Observation on the Apoptosis Induced by H_2O_2 in Protoscolex of Echinococcus granulosus / 中国寄生虫学与寄生虫病杂志

ABSTRACT

Objective To explore the apoptosis induced by hydrogen peroxide ( H2O2) in protoscolex of Echinococcus granulosus. Methods Protoscoleces were cultured in vitro, and used for the experiment in 2 groups RPMI 1640 medium and RPMI 1640 medium added with glutamine. They were then treated with different concentrations of H2O2 to induce apoptosis. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay (TUNEL) was employed to observe the apoptosis. Protein expression of caspase-1, caspase-3 and Fas was detected by SP immunohistochemical technique, stained with DAB restained with hematoxylin. A yellow or brown color nucleus revealed positive apoptosis cells in protoscolex, a brown reaction product in cytoplasm showed positive cells of caspase-1 and caspase-3, and brown cell membrane and cytoplasm revealed Fas product; otherwise it was judged as negative. According to the percentage of positive cells in a protoscolex, the expression level was divided as 4 grades. The percentage of less than 5% was regarded as "-", 5%-25% as "+", 26%-50% as "++", more than 50% as "+++". The experiments were repeated 2 times with controls. Results In RPMI 1640 group, positive TUNEL was found in the protoscolex induced by 1 mmol/L H2O2 inducing for 12 hours. Induced by 1 mmol/L H2O2 for 4 h, the "+ -++" expression rate of caspase-1 and caspase-3 in the protoscoleces was 86.6% and 77.8% , and for 8 h, 86.6% and 80.0% respectively, a significant increase in comparison to the control (P