UV-induced Nucleotide Excision Repair (NER) and Photoreactivation Repair (PER) in two trout fish cell lines used in ecotoxicological assessment studies

• RTL-W1 and RTG-W1 show the same sensitivity profile to low UVC doses.
• Modified T4-PDG comet assay allowed to detect cyclobutane pyrimidine dimer repair kinetics in the two cell lines.
• Both cell lines express efficient PER but rather slow NER, with gill cells repairing slightly faster than liver cells.

A better knowledge of DNA repair capacities in permanent fish cell lines would contribute to establish their interest in genotoxicity testing for environmental risk assessment studies including the effects of an increase in solar UV radiations on aquatic organisms. NER (Nucleotide Excision Repair) and PER (Photoreactivation Repair) are the two repair pathways of choice for UV-induced photo-lesions. In the present paper, these repair processes were characterized in the two rainbow trout cell lines, RTGill-W1 and RTL-W1 (liver), by means of a T4-modified comet assay which allowed to follow the cyclobutane pyrimidine dimers repair kinetics specifically. Both repair processes have been found in the cell lines, PER repairing much faster UV lesions than NER, and NER being slightly more efficient in the gill cell line than in the liver one.