Establishment and characterization of fibroblast cell lines from the skin of the Yangtze finless porpoise

The Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis), as the sole freshwater subspecies of N. phocaenoides, is endemic to the Yangtze River and its adjacent lakes. Its population has declined significantly over recent decades. In this study, we established a skin-derived finite fibroblast cell line of the Yangtze finless porpoise, named YFP-SF1, using primary cell culture methods, and an immortalized cell line, T-YFP-SF1, through co-transfection (GFP and SV40 T antigens) techniques. YFP-SF1 proliferated continuously with a minimum population doubling time of 31 h and exhibited age-dependent changes in growth rate. T-YFP-SF1 cells exhibited fibroblast morphology and were characterized by a shorter doubling time, higher attachment efficiencies, colony formation at a low seeding density, and growth in low serum concentrations. Anchorage independence and foci formation in the cell monolayer were observed from passage 36. The chromosome number of YFP-SF1 and T-YFP-SF1 remained stable at 2n = 44 in the early passages, and the viability of thawed cells remained above 90% after cryopreservation in liquid nitrogen. Taken together, we have established fibroblast cell lines of Yangtze finless porpoise for the first time, which might assist as an in vitro model for this endangered mammal.