Serious lipid mobilization in adipose tissue of dairy cow is the pathological basis of ketosis and fatty liver. Many Studies demonstrated that pre-adipocytes are unstable and can differentiate into multiple cells in vitro. The aim of this study was to investigate the differentiation process of dairy cow pre-adipocytes and to establish a stable pre-adipocyte induction method. Pre-adipocytes were isolated from dairy cow adipose tissue and were cultured for 15 days. The originally rounded cells converted to a spindle fibroblast-like morphology and accumulated lipids during culturing. The lipid droplets and TG content in the adipocytes gradually increased from 4 to 15 days in culture. The adipocytes reached maximal proliferation after 11 days in culture. Additionally, the expression of peroxisome proliferator-activated receptor γ2 (PPARγ2) and sterol regulatory element binding protein 1c (SREBP-1c) increased during the initial 4 days of differentiation and decreased thereafter. However, the level of SREBP-1c increased after 10 days of differentiation. The PPARγ2 and SREBP-1c proteins levels were significantly higher on day 13 than on day 0. PPARγ2 and SREBP-1c were primarily localized to the cytoplasm on day 0 and to the cytoplasm and nucleus on day 13. In conclusion, a stable dairy cow pre-adipocyte culture was established, and SREBP-1c and PPARγ2 were increased during (demonstrated to be involved in) pre-adipocyte differentiation. Isolated adipocytes can be used as a cellular model to elucidate the process of lipogenesis in dairy cows and to further investigate metabolic diseases.

Key words: Adipocyte differentiation, Dairy cows, Insulin, Pre-adipocyte