Evaluation of Copper-Induced Cytotoxicity and Transcriptomic Change Using a RTgill-W1 Cell Line as an Alternative Replacing Fish Test

The RTgill-W1 cell line serves as an alternative for acute fish toxicity testing. This study aims to study the reliability of the RTgill-W1 cell line in copper cytotoxicity using transcriptomic analysis followed by comparison with existing literature. As a result, the study found that the average EC50 (375 μg/L ± 181 μg/L) in cell viability was similar to previous literature results (0.093-530 μg/L), suggesting the system's reliability as an alternative. The transcriptome changes of the RTgill-W1 cell line caused by copper exposure are supported by the existing literature on individual fish. For example, osmoregulatory disturbances, regulation of Na⁺/K⁺-ATPase activity, oxidative stress, apoptosis, energy metabolism alterations, metal detoxification, and chaperone protein expression were found in the RTgill-W1 cell line in response to copper exposure, indicating the utility of this cell line for transcriptome analysis. Finally, through RT-PCR confirmation and literature analysis, this study suggests that <i>sirtuin 1</i>, <i>sirtuin 4</i>, <i>Na⁺/K⁺-ATPase</i>, <i>aifm4</i>, <i>bcl2</i>, <i>carbonic anhydrase</i>, <i>hsp70</i>, <i>hsp30</i>, and other biomarkers could be used for detecting copper stress in aquatic organisms. This study is helpful for understanding the toxicity mechanism of copper and can be referred to as scientific data for regulating copper release into the aquatic environment.