Target gene expression signatures in neutrophils and lymphocytes from cattle administered with dexamethasone at growth promoting purposes.

ABSTRACT

The glucocorticoid dexamethasone (DEX), when used as a growth promoter, cause morphological and functional alterations in cattle lymphoid organs and cells. In the present experiment, the transcriptional effects of an illicit DEX protocol upon six target genes were investigated in cattle neutrophils (NEU) and lymphocytes (LFC). Blood samples were taken before (T(0)) and 2, 3, 10, 19, 31 and 43 days from the beginning of DEX administration (T(1)-T(6)). Leukocytes were counted and cells isolated by gradient centrifugation; then, glutathione peroxidase 1 and 3 (GPX1 and GPX3), glucocorticoid receptor alpha (GRα), l-selectin, nuclear factor κB, subunit p65 (NFκB) and tumor necrosis factor alpha (TNFα) mRNA amounts were measured through a quantitative Real Time RT-PCR approach. A significant change vs controls in NEU/LFC ratio was noticed from T(3) forward. Compared to T(0), DEX significantly increased to a variable extent all candidate gene mRNAs abundances in NEU; in contrast, only l-selectin, GRα and GPX1 were significantly up-regulated in LFC. Present results suggest that illicit DEX affects transcription in cattle immune cells, that might be considered as a promising surrogate tissue for the screening of DEX abuse in cattle farming.