Selenium Deficiency Promotes Oxidative Stress-Induced Mastitis via Activating the NF-κB and MAPK Pathways in Dairy Cow

Selenium (Se) is an antioxidant and immunomodulator that can participate in the control of specific endocrine pathways. Disturbance of redox homeostasis is closely related to the pathogenesis of many diseases. Se is also an important nutrient element for dairy cows. First, oxidative stress (OS) induced by Se deficiency was investigated along with a possible mechanism of its induction of mammary gland inflammation. This investigation used in vivo and in vitro experiments for verification. Once the OS response was triggered, the activity of antioxidant enzymes was reduced by regulation of the concentration of Se, which led to the accumulation of ROS. TNF-α, IL-1β, and IL-6 secretion was promoted to activate the NF-κB/MAPK signaling pathway. This process further promoted the accumulation of cytokines that aggravated the inflammatory response. Herein, it was verified that Se deficiency induces OS, which leads to ROS accumulation and the secretion of inflammatory factors to activate the NF-κB/MAPK signaling pathway and promote the occurrence of mastitis.