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(22-40) Induction and recovery of intestinal biochemical and quantitative cytological changes in fish by foodborne PAH. Yuen, Bonny*,1, Pollino, Carmel1, Au, Doris1, 1 Center for Coastal Pollution and Conservation, City University of Hong Kong, Kowloon Tong, Hong Kong ABSTRACT- The response of intestinal monooxygenases to dietary benzo[a]pyrene (B[a]P) was evaluated in the juvenile grouper Epinephelus areolatus. Fish were force-fed daily with pellets containing B[a]P dissolved in DMSO at 0.25 mg B[a]P / g body weight (low dose) and 12.5 mg B[a]P / g body weight (high dose). Control fish were given pellets containing DMSO only. Intestinal ethoxyresorufin-O-deethylase (EROD) and aryl hydrocarbon hydroxylase (AHH) activities were measured over a 4-week exposure and a 4-week depuration period. The highest induction in EROD activities was observed after 1 week exposure to BaP, with levels increased 327-fold for low dose and 502-fold for high dose. AHH activities peaked at week 4 with levels increased 69-fold and 23-fold for low dose and high dose, respectively. Both EROD and AHH activities decreased to the control levels after 7 days of depuration. Induction of EROD and AHH activities in intestine and liver will be compared. Parallel ultrastructural study showed that B[a]P induced cytological alterations in absorptive columnar cells and goblet cells in intestine. Major symptoms observed include: i) reduction of brush border in mucosal epithelium, ii) accumulation of inclusion bodies in the apical cytoplasm of columnar epithelium, iii) increase in rough endoplasmic reticulum in basal mucosal cells, iv) swollen mitochrondria with loss of mitochrondrial matrix; v) infiltration of macrophages and lymphocytic cells; and vi) increase in size of goblet cells. Entero-cytological changes will be quantified using stereology and related to EROD and AHH activities, with an objective to link exposure biomarkers for PAHs (i.e. EROD/AHH activities) to significant biological effects (i.e. enterocytological damage). Key words: PAHs, biomarkers, stereology, fish intestine |
