EVALUATION OF TNF-a, IL-8 AND IL-10 TRANSCRIPTIONAL ACTIVITY IN MILK FROM HEALTHY DAIRY COWS DURING LACTATION PERIOD

In milk cells from 50 healthy Holstein cows, expression levels of tumor necrosis factor-alpha (TNF-a), interleukin-8 (IL-8), and interleukin-10 (IL-10) were investigated by Real-Time TaqMan® polymerase chain reaction (PCR) systems. Samples from early- and late-lactation stages tended to express lower levels of TNF-a and IL-8 than did those from mid-lactation. On the contrary, the IL-10 expression level in samples from early- and late-lactation tended to be higher than in mid-lactation samples. Cytokines transcription in late-lactation was more co-ordinated in their transcriptional activity. The results suggest that the lactation stage-dependent changes of the quantitative cytokine mRNA profiles are crucial for monitoring the well-being of the mammary gland.