Establishment and application of a brain cell line derived from Plectropomus leopardus

Plectropomus leopardus is an economically valuable marine farmed fish. However, diseases have seriously restricted the healthy development of its breeding industry. Cell line is an important in vitro research system in the fields of disease control, environmental toxicology, nanotechnology, and so on. However, the application of marine fish cell lines is far from the expected level, and many species have not yet been reported to establish cell lines. In our study, we developed a brain cell line derived from P. leopardus, designated as PLB, and investigated its susceptibility to bacterial agents and heavy metal exposure. The findings indicated that PLB cell lines grew fastest in L-15 medium supplemented with 20 % fetal bovine serum (FBS) at 26 °C. The established cell line was identified by 18 S rRNA gene sequencing as being derived from P. leopardus. Chromosome analysis revealed that the PLB cell line had a chromosome count of 48. The transfection efficiency of PLB cells was about 27 % by liposome transfection method, indicating that PLB cell lines offer utility for conducting functional investigations of exogenous genes. In addition, the bacterial sensitivity analysis results indicated that PLB cells exhibited susceptibility to both Vibrio harveyi and Edwardsiella tarda, furthermore, PLB cells displayed heightened sensitivity towards V. harveyi in comparison to E. tarda. The outcomes from the heavy metal toxicity experiments demonstrated significant toxicity of three heavy metals (Hg²⁺, Cu²⁺ and Cd²⁺) towards PLB cells, with Hg²⁺ exhibiting the highest degree of toxicity among them. Moreover, there was a dose-dependent relationship between cell survival rate of PLB and heavy metal concentration. In summary, PLB cell lines represent a promising tool for conducting in vitro analyses of foreign gene functionality, bacterial susceptibility, and heavy metal toxicity. It helps ensure the safety of aquatic breeding environments and also supports genetic enhancements in fish fry, promoting the development of traits such as increased growth and disease resistance, which are vital for aquaculture progress.