Hepatic cellular and tissue pathologic response in the mosquito fish, Gambusia affinis, to different time exposure of diethylnitrosamine

• Published in: Marine environmental research 1996-10, Vol.42 (1), p.108-109
• Main Authors: Couch, J.A., Diamant, A.
• Format: Article
• Language: English
• ISSN: 0141-1136; 1879-0291
• DOI: 10.1016/0141-1136(96)87049-8

In order to determine the range of response to different times of exposure, different groups of the mosquito fish, Gambusia affinis, were exposed to 80 mg/l diethylnitrosamine (DEN) for three different time periods: 4, 15 and 28 days. Three different samples of fish from each exposure group were taken within a 365-day period during holding in clean water. The incidence of hepatic lesions, kinds of lesions induced, and severity of lesions were studied. Four-day exposed fish showed minimal necrotic neoplastic response during the 365-day holding period. After 727 days (2 years) holding, however, a minimal hepatic, neoplastic response occurred in long-term survivors of the four-day exposure group. Fifteen-day exposed fish had moderate to strong necrotic and neoplastic responses, including adenomas (A), cholangiocellular carcinoma (CC), and hepatocellular carcinomas (HCC). Twenty-eight day exposed fish demonstrated the most severe necrotic, degenerative, and neoplastic responses (A, CC, HCC), including invasive HCC. This study demonstrated the importance of relative exposure period in response potential of this species to a known carcinogen. It further demonstrated the broad qualitative response potential in terms of various lesion types induced. The mosquito fish may be an excellent field and laboratory model for carcinogen studies.