Short communication: Localization and expression of monocyte chemoattractant protein-1 in different subcutaneous and visceral adipose tissues of early-lactating dairy cows

The present study aimed to examine the mRNA abundance of the monocyte chemoattractant protein-1 (MCP-1) and to localize the MCP-1 protein in different subcutaneous (s.c.) and visceral (v.c.) fat depots in high-yielding dairy cows. Early-lactating German Holstein cows (n = 25) were divided into a control (CON) and a conjugated linoleic acids (CLA)-supplemented group to investigate potential effects of dietary CLA treatment on MCP-1. The MCP-1 was localized in different s.c. and v.c. adipose tissue (AT) by immunohistochemistry, whereas the mRNA abundance was investigated using quantitative PCR. Albeit the infiltration of immune cells into bovine AT has been demonstrated to be only marginal, both MCP-1 protein and mRNA could be detected in bovine AT depots. The MCP-1 protein was localized both in the cytoplasm of adipocytes and in the cytoplasm of cells from the stromal vascular fraction; however, the number of MCP-1-positive cells was low. The mRNA abundances of MCP-1 were higher in v.c. compared with s.c. AT. Moreover, neither mRNA abundance nor protein expression of MCP-1 was seriously influenced by CLA supplementation of early-lactating dairy cows.