New insights into the significance of PARP-1 activation: flow cytometric detection of poly(ADP-ribose) as marker of bovine intramammary infection

Bovine intramammary infections are common diseases affecting dairy cattle worldwide and represent a major focus of veterinary research due to financial losses and food safety concerns. The identification of new biomarkers of intramammary infection, useful for monitoring dairy cows’ health and wellness verification, represents a key advancement having potential beneficial effects on public health. In vitro experiments, using bovine peripheral blood mononuclear cells (PBMC) stimulated with the bacterial endotoxin lipopolysaccharide (LPS) allowed to perform a flow cytometric assay to evaluate in vivo poly-ADP-ribose (PAR) levels. Results showed a significant increase of PAR after 1h of treatment, which is consistent with the involvement of PARP activity in the inflammatory response. This study investigated PARP-1 activation in leukocyte subpopulations from bovine milk samples during udder infection. A flow cytometric assay was therefore performed to evaluate the PAR content on milk leukocytes subsets of cows with and without intramammary infection (IMI). Results showed that milk lymphocytes and macrophages isolated from cows with IMI had a significant increase of PAR content compared to uninfected samples. These results suggest mastitis as a new model for the study of the role of PARP in zoonotic inflammatory diseases, thereby opening new horizons for the "One Health" perspective connecting animal and human health.