The in vitro effect of mefloquine and praziquantel against juvenile and adult Schistosoma japonicum

Abstract

Mefloquine, an antimalarial drug, has been found to be effective against various stages of schistosomes in vivo. The purpose of the study is to explore the in vitro effect of mefloquine against adult and juvenile Schistosoma japonicum and to compare its efficacy with praziquantel. Three-hour-old schistosomula were prepared by penetrating the mouse skin with schistosome cercariae, while schistosomes 7-, 14-, and 35-day-old were collected from mice infected with S. japonicum cercariae for 7, 14, and 35 days by perfusion. Schistosomes were placed to each of 24 wells of a Falcon plate and maintained in Hanks' balanced salt solution-20% calf serum. Besides observation on the direct in vitro effect of mefloquine and praziquantel, adult worms exposed to mefloquine and praziquantel for 1 and 4 h were transferred to the medium without the drugs and incubated continuously for another 72 h. The reversible effect of mefloquine and praziquantel was assessed by the recovery of the worm motor activity and parasite survival. The minimal effective concentration of mefloquine against adult schistosomes in vitro was 10 microg/mL, which revealed that the worm motor activity was first stimulated, then decreased significantly, followed by bleb formation, focal swelling and elongation of the worm body, cessation of gut peristalsis, and death of 56.3% (18/32) worms within 24-72 h. Similar appearance was seen in the adult worms exposed to higher mefloquine concentration of 20 and 30 microg/mL, but all worms died within 4-24 h. The adult schistosomes exposed to praziquantel 1-30 microg/mL showed fast spasmodic contraction of the worm body, followed by bleb formation along the tegument, feeble movement of oral sucker, and death of a part of males and females 72 h after incubation. When male and female schistosomes exposed to mefloquine 10 and 20 microg/mL for 1 and 4 h were transferred to the medium without the drug, no apparent recovery of worm motor activity and survival was seen. In case of worms exposed to praziquantel at the same concentration for 1 and 4 h before replacement of drug-free medium, a well recovery of worm motor activity, looseness of worm body, and reduction or disappearance of blebs along the tegument were observed. Mefloquine also exhibited in vitro effect against 3-h-old and 7- and 14-day-old schistosomula which was similar to that seen in adult worms, but all or parts of worms showed decrease in motor activity or even death (3-h-old and 7-day-old schistosomula) at a lower mefloquine concentration of 5 microg/mL. In 14 day-old schistosomula exposed to praziquantel 1-30 microg/mL, spasmodic contraction and significant decrease in motor activity of the worm body with movement of oral and ventral suckers were observed, but no death of worm was seen during a 3-day incubation period. The results indicate that in vitro mefloquine exhibits a direct killing effect against adult and juvenile S. japonicum which is different from that of praziquantel. Meanwhile, the juvenile schistosomes are more susceptible to mefloquine than ...

Efficacy and side effects of praziquantel in the treatment of Schistosomiasis mansoni in schoolchildren in Shesha Kekele Elementary School, Wondo Genet, Southern Ethiopia

“…A cross sectional study was carried out in which 304 children were randomly selected from 8 sections (grade 3 to 8) in the study in Shesha Kekele elementary school in April 2010. However, only 299 children volunteered to take part in the study.…”

“…Among children randomly selected from Shesha Kekele Elementary School (grades 3 to 8) in Wondo Genet, southern Ethiopia, 299 children volunteered and provided stool sample. The mean age of the study population was 11.4 (age range: 6 to 22 years) with the highest proportion of individuals lying in the [10][11][12][13][14] Most of the S. mansoni infected children were either cured or the intensity of infection became significantly reduced.…”

“…Recently, schistosomicidal compounds such as artemether and mefloquine have been studied for their efficacy against schistosomes [6][7][8][9] . However, praziquantel (PZQ) remains the drug of choice in the treatment of schistosomiasis since the 1970s [10][11][12] .…”

Curcuma longa extract nanoemulsion preparation and demonstration of its in vitro activity against Schistosoma mansoni cercariae, schistosomules and adult stages

“…The maintenance and care during experimentation of animals was compliant with international guidelines for the human use of laboratory animals. Adult worms were removed from portal and mesenteric veins of infected mice after 90 days [29] , sexed and counted [30] . Six to ten mature worms including both sexes were cultured per well in 24-well plates containing RPMI medium at 37°C and 5% CO 2 , immediately after animal perfusion to ensure their vitality.…”

“…Negative control wells contained adults incubated in culture media. All experiments were performed in duplicates and read at 24, 48 and 72 h post treatment [30] . The effect of Cl nanoemulsion concentrations on S. mansoni adult worms were monitored every 24 h during 96 h for evaluation of their motor activity.…”