Ultrastructural Changes in Ascaris suum Intestine after Mebendazole Treatment In vivo

Abstract

The effect of in vivo treatment with mebendazole on the ultrastructural morphology of Ascaris suum intestine was investigated. Pigs, infected with A. suum, were fed ad libitum a medicated food containing mebendazole at a concentration of 30 ppm. Control and treated animals were killed 6, 9, 15, and 24 hr after the onset of feeding. The parasites were quickly collected from the pig intestinal tract and prepared for ultrastructural and cytochemical examination. Absence of secretory granules in the terminal web, accumulation of secretory granules in the Golgi region, formation of autophagic vacuoles in the apical cell part, and loss of glycogen were the characteristic changes observed after 6 and 9 hr of treatment. Degenerative changes were very pronounced after 15 and 24 hr and involved almost the entire cytoplasm. Microvilli were decreased in number and appeared swollen in the majority of absorptive cells. Some more severely altered cells were completely devoid of microvilli. Cytochemistry revealed that the accumulated secretory granules in the Golgi area contained glycoproteins or polysaccharides. Microvilli, lysosomes, and Golgi apparatus were reactive for acid phosphatase in the control intestinal cells. After treatment, the enzyme activity was localized in numerous autophagic vacuoles, whereas the secretory granules remained unstained. The acid phosphatase activity in the microvilli decreased or was completely absent. The possible significance of these modifications in view of mebendazole's anthelmintic activity is discussed.

A light and electron microscopic study on the synergistic effect of pyrantel and the febantel metabolite febendazole on adult Toxocara canis in vitro

“…The reason for this may be that a portion of fenbendazole is also taken up orally. This observation is in line with results obtained by Borgers and De Nollin (1975) investigating mebendazole effects in Ascaris suum. However, the path of drug uptake can ultimately only be elucidated by autoradiography.…”

Mode of action, selectivity and mutagenicity of benzimidazole compounds

“…Mebendazole induces degenerative changes in the intestinal cells of parasitic worms after treatment of their hosts (Borgers and De Nollin, 1975).…”

Anthelmintic drugs and nematicides: studies in Caenorhabditis elegans

“…Over 40 years ago it was shown that tetramisole (Aceves et al, 1970) and pyrantel (Aubry et al, 1970) both act as nicotinic receptor agonists and elicit spastic muscle paralysis due to prolonged activation of the excitatory nicotinic acetylcholine receptors (nAChRs) on body wall muscle of nematodes. Voltage-clamp studies using A. suum body wall muscle cells have shown that morantel, pyrantel, and levamisole mimic the actions of acetylcholine, with the following order of potency: morantel=pyrantel>levamisole>acetylcholine (Harrow and Gration, 1985).…”