Comparative studies on animal models for Opisthorchis viverrini infection: host interaction through susceptibility and pathology

Abstract

Syrian hamsters and gerbils are animal models for Opisthorchis viverrini infection. In both models, the parasites develop into adults with different pathologies of the hepatobiliary system. However, no comparative pathological studies have yet been completed. We therefore investigated host interaction through the susceptibility and pathological changes of Syrian hamsters and gerbils infected with 50 O. viverrini metacercariae for 30, 60, and 90 days post-infection. Animals were sacrificed at each time point for comparative study. Susceptibility and infectivity were investigated through worm burden. Parasite morphology and reproductive organs were stained with carmine and observed under light microscopy. Reproductive organs and eggs per worm were counted to confirm worm maturity. Bile acid components of both animal groups were analyzed by thin-layer chromatography. The results showed that infection in gerbils was of greater severity than in Syrian hamsters by observation of bile obstruction, enlargement of the gallbladder and common bile duct, and generation of fibrosis and cirrhosis. The worm burden of infected gerbils was lower than that observed in Syrian hamsters. Infectivity in both Syrian hamsters and gerbils was 100% with infection by 50 metacercariae; whereas with 10 metacercariae, the infectivity in gerbils was zero to very low, but still 100% in Syrian hamsters. The largest body size of worms, and the largest ovary and testes areas, was correlated with eggs per gram of feces and eggs per worm. The bile acid components cholic acid and chenodeoxycholic acid were undetectable in gerbils. The present study suggests that although Syrian hamsters, usually the host selection for an animal model, are susceptible to O. viverrini infection, infected gerbils produce worms that mature more rapidly, have larger body sizes, and more fully developed reproductive organs; this may be caused by the difference in bile acid components.

The Carcinogenic Liver Fluke Opisthorchis viverrini is a Reservoir for Species of Helicobacter

“…It has been suggested that the ‘acidification’ of bile through reflux into the low pH of the stomach precipitates inhibitory bile acids, thereby allowing colonization by H. pylori (Hynes et al, 2003; Shao et al, 2008). In case of opisthorchiasis, the infection by the flukes can disturb bile acid composition (Wongpaitoon et al, 1988; Wonkchalee et al, 2012) that may reduce alkalinity of the bile, leading to damage to biliary epithelia and inflammation (Strazzabosco et al 2000). All these phenomena may facilitate conditions that favor colonization by Helicobacter during concurrent infection with liver flukes.…”

Infection with the carcinogenic liver fluke Opisthorchis viverrini modifies intestinal and biliary microbiome

“…Biliary inflammation has been linked with ulcerative colitis and hence O. viverrini ‐induced perturbations of microbial communities could contribute to inflammation by exposing the cholangiocytes to microbes or metabolites of enteric or parasite‐associated microbes (7, 8) and recruitment of mucosal lymphocytes to the biliary system (69). In addition, perturbations in the microbiota may be responses to bile constitution, since O. viverrini infection affects composition and concentration of bile acids (70, 71). Bile acid composition influences gut microbiota (72) and can promote pathobiont expansion and inflammation (73).…”

Histopathological Changes in Tissues of Bithynia siamensis goniomphalos Incubated in Crude Extracts of Camellia Seed and Mangosteen Pericarp

“…After 24 hr exposure, only live B. siamensis goniomphalos snails from each group (untreated control, camellia-treated, mangosteen-treated, and niclosamide-treated), were processed for analysis of histopathological changes by hematoxylin and eosin staining, following previous reports [22-24]. In brief, B. siamensis goniomphalos snails were fixed with buffered 10% formalin solution for 1 week and then washed with PBS solution for 15 min 3 times.…”