Fig. 2

Opisthorchis viverrini (OV)-induced cholangiocarcinoma and 8-nitroguanine formation. a Life cycle of OV. Eggs laid from adult worms in bile ducts are passed through the bile into the duodenum and excreted with feces. Eggs hatch in the digestive tracts of Bithynia snails (first intermediate host). Free-living cercariae transform to metacercariae encysted mainly in the muscle of fish (second intermediate host). Metacercariae are infective to humans, when they ingest raw or inadequately cooked fish. Metacercariae are digested and excysted juvenile flukes migrate up through the bile duct. b 8-Nitroguanine formation in bile duct epithelium of an OV-infected hamster. Male Syrian hamsters were infected with OV for 30 days, and praziquantel was given orally 7 days before sacrifice. Paraffin sections of liver tissues were incubated first with rabbit polyclonal anti-8-nitroguanine antibody and then with Alexa 594-labeled goat anti-rabbit immunoglobulin G (IgG). The immunoreactivity of 8-nitroguanine was seen in the nucleus of bile duct epithelial cells, and its formation diminished after praziquantel treatment [38]. Scale bar 25 μm