Progress has been made over the last decade with the development
and clinical use of artemether as an agent against major human schistosome
parasites. The tegument has been identified as a key target of artemether,
implying detailed studies on ultrastructural damage induced by this compound.
We performed a temporal examination, employing a transmission electron microscope
to assess the pattern and extent of ultrastructural alterations in adult
Schistosoma mansoni
harboured in mice treated with a single dose of 400 mg/kg artemether. Eight
hours post-treatment, damage to the tegument and subtegumental structures
was seen. Tegumental alterations reached a peak 3 days after treatment and
were characterized by swelling, fusion of distal cytoplasma, focal lysis
of the tegumental matrix and vacuolisation. Tubercles and sensory organelles
frequently degenerated or collapsed. Typical features of subtegumental alterations,
including muscle fibres, syncytium and parenchyma tissues, were focal or
extensive lysis, vacuolisation and degeneration of mitochondria. Severe
alterations were also observed in gut epithelial cells and vitelline cells
of female worms. Our findings of artemether-induced ultrastructural alterations
in adult
S. mansoni
confirm previous results obtained with juvenile
S. mansoni
and
S. japonicum
of different ages.
