Research on in vitro culture and inducing nacre crystal formation of freshwater pearl mussel mantle epithelial cell Sinohyriopsis cumingii

Abstract

The foundation of natural pearl formation by mussels is calcium carbonate in the form of aragonite crystals, 
secreted essentially by the epithelial cells of mantle tissue as nacre. The in vitro explant culture of nacre secreting 
pallial mantle explants of freshwater pearl mussel was a vital step in the approach to the establishment of quality of 
pearl mussel species, by screening pearl mussel species that are able to form pearls with high efficiency. Moreover, 
the results of this research provide knowledge for the future in vitro colored pearl production. The aims of this 
research were to culture freshwater pearl mussel mantle epithelial cells and to investigate the capacity of their 
nacre-secretion when they were induced by some specific factors such as Ca2+, FGF-2 and EGF. In this research, 
mantle epithelial cells were cultured in four different kinds of medium (DMEM/F12, L15-M199, IMDM, TCM) and 
temperature [(4, 24°C and room temperature (28°C)] to select the suitable environment for pearl mussel mantle 
epithelial cell culture for at least one month. After that, old medium was changed by fresh medium supplemented 
with three inducers (Ca2+, FGF, EGF). Nacre secretion of these cells was evaluated via the nacre formation in culture 
medium. The results showed that the mantle epithelial cells may be cultured in vitro and secrete nacre in DMEM/F12 
medium supplemented with 10% FBS, but the efficiency of secretion was independent with different inducers 
investigated. DMEM/F12 medium is the best for growing of mantle epithelial cells while IMDM medium is suitable for 
heamocyte –like cells.