Abstract
Myokine abundance and function have not been thoroughly evaluated in beef cattle. Many myokines have been shown to have a substantial impact on the health and well-being of mammals. While interleukin 6 (IL-6) is a known immune cytokine, it is also classified as a myokine and in mice is produced from muscle contraction post-exercise. IL-6 is linked to muscle hypertrophy through the action of increasing glucose uptake and stimulating satellite cell proliferation. The objective of this study is to characterize temporal IL-6 production by cultured primary bovine satellite cells (BSCs) in 11-month-old beef steers. IL-6 abundance was quantified in in vitro cultured undifferentiated primary BSCs isolated from 11-month-old steers. This experiment had 3 experimental replicates where cells were plated in triplicate with 10% Fetal Bovine Serum in DMEM. At 70% confluency the growth media was changed, and this was classified as time zero. The media then remained unchanged and was collected temporally at 0, 12, 24, and 48 hours. Media was assayed using Bovine IL-6 ELISA’s to quantify myokine abundance. Cells were also harvested for mRNA extraction and analyses at a future time. We are in the initial stages of the analyses, though preliminary data indicate no difference in IL-6 abundance between the BSC pools isolated from different steers. Temporally, we report that at hour 0 there is undetectable IL-6 concentration, but at 12, 24, and 48 hours there is a steady concentration of IL-6 released into the growth media by the BSCs. This confirms that IL-6 is being produced by BSCs from post-weaned, beef steers. We conclude that myokine; IL-6 is involved in post-natal skeletal muscle growth of beef cattle.