Effects of mebendazole, albendazole, and praziquantel on glutathione S-transferase and superoxide dismutase of Echinococcus granulosus cyst wall harbored in mice

AIM: To explore the existence of glutathione S-transferase (GST) and superoxide dismutase (SOD) in Echinococcus granulosus cyst, and the effect of anthydatid drugs on these 2 enzymes, mice infected with E granulosus protoscoleces for 10-12 months were used. METHODS: The activity of GST was measured by conjugation rate of 1-chloro-2,4-dinitrobenzene with glutathione (reduced form), while the activity of SOD was measured by a modified autoxidation of 1, 2, 3-trihydroxy-benzene method. RESULTS: Activities of both GST and SOD in the cyst wall were 12.3 +/- 4.3 to 13.5 +/- 4.8 mumol min-1/mg protein and 4.4 +/- 2.9 to 6.1 +/- 1.4 U min-1/mg protein, respectively. When infected mice were treated ig with mebendazole (Meb) 25 mg kg-1 d-1 for 14 d, the GST activity of both collapsed and full cyst walls were inhibited by 30.1% and 26.8%, respectively. Whereas SOD activity of the cyst walls were activated by 105%-163%. Albendazole 300 mg kg-1 d-1 for 14 d and praziquantel 500 mg kg-1 d-1 for 14 d had no apparent effect on both GST and SOD of E granulosus cyst wall. CONCLUSION: The results suggested that the inhibition of GST activity in the cyst wall induced by Meb might damage the defence system of the parasite.