Acute toxic effects of lead (Pb2+) exposure to rare minnow (Gobiocypris rarus) revealed by histopathological examination and transcriptome analysis.

Lead (Pb) is a toxic heavy metal that can cause significant damage to the aquatic ecosystem. In this study, acute toxicity test of lead in rare minnow (Gobiocypris rarus) was conducted. The average LC50 for 96 h of Pb2+ is 423.01 μg/L (95 % CI: 338.41-531.92 μg/L). The order of bioaccumulation of Pb2+ was gills > kidney > intestine > liver > muscle > brain. A number of cellular and tissue alterations were observed in the gill, liver, kidney and intestine tissues of Pb2+-treated rare minnows through the histological examination performed by H&E and TEM analyses. Furthermore, we investigated the Pb2+-induced toxicity mechanisms in rare minnow based on transcriptome analyses, and a panel of immune-related genes were identified and evaluated by real-time quantitative PCR. In summary, our work indicates that rare minnow could be a valuable model for studying the mechanisms of lead acute toxicity in fish.