Ultrastructural and muscular modifications of adult schistosoma mansoni worms induced by artemether [ART] in vitro

ABSTRACT

Schistosomiasis is one of the most important public health problems worldwide. In spite of two decades of safe and effective widespread chemotherapy with praziquantel, the number of individuals with schistosomiasis remains high with the appearance of drug resistance. So, it diverts the attention to other anti-parasitic drugs like artemesinin derivatives e.g. artemether [ART]. This study was done to assess the effects of ART on the tegument and musculature of adult Schistosoma mansoni worms in vitro. Five groups of S. mansoni coupled adult worms, each of 10 couples, were used. Four groups were tested in vitro using different concentrations of ART [20, 40, 80 and 100microg/ml] for 24 hours of exposure. These adult worms were obtained by hepatic perfusion technique seven weeks postinfection by 100+/-10 S. mansoni cercariae in male white albino mice using tail immersion method. Ultrastructural and muscular modifications of adult S. mansoni worms were assessed using Scanning Electron Microscopy [SEM] and a special device respectively. SEM examination revealed that after 24 hours of exposure to 40microg/ml ART, the tegument showed vesicles and loss of spines. On exposure to 80microg/ml ART, the tegument showed cracking and more loss of spines. After exposure to 100microg/ml ART, tegument appeared mostly distorted with cracking, peeling, bleb formation and the spines covering the tubercles appeared to be partially lost. ART elicited muscle contraction and reached the highest response with 100microg/ml ART. The maximal increase in muscle tension [% shortening of worms] was 44.1 +/- 1.79 % shortening induced by the highest concentration [100microg/ml] of ART