The Effect of Hydrocortisone on Milk Fat Synthesis in Bovine Mammary Epithelial Cells

Abstract: The aim of this study was to explore the effects of hydrocortisone (HYD) on proliferation， synthesis of triglyceride， formation of lipid droplets and expression of genes involved in milk fat synthesis of bovine mammary gland epithelial cells (BMECs). A single factor randomized trial design was applied. Different concentrations (0， 1， 10， 100， 1 000 ng/mL) of HYD were added in culture medium of BMECs for 24 h. Cell viability was detected by thiazoly blue tetrazolium (MTT). Triglyceride (TAG) content was measured by TAG determination kit. Expression of genes involved in milk fat synthesis were measured by real time quantitative PCR (RT-qPCR). The results showed that the activity of cell proliferation was not influenced by supplementation of HYD (P>0.05). Compared with the control group， 100 ng/mL HYD significantly increased the concentration of TAG and the formation of intracellular fat droplets， the expression of peroxisome proliferator activated receptor γ (PPARγ) was also upregulated (P<0.05). 10 ng/mL and 100 ng/mL HYD significantly increase the gene expressions of acetyl-CoA carboxylase (ACC) and diacylgycerol acyltransferase (DGAT) (P<0.05); 1， 10， 100 ng/mL HYD significantly upregulated the mRNA level of fatty acid synthase (FASN)， whereas 1 000 ng/mL HYD was significantly downregulated the mRNA level of FASN (P<0.05). In conclusion， HYD treatment can promote milk fat synthesis in BMECs and the 100 ng/mL HYD is an optimal level considering its improvement effects on milk fat synthesis of BMECs.

CSTR: 32200.14.cjcb.2017.09.0004