Deoxynivalenol induces oxidative stress, inflammatory response and apoptosis in bovine mammary epithelial cells.

Abstract

Deoxynivalenol (DON) is a toxic secondary metabolite produced by Fusarium graminearum. It is one of the most common feed contaminants that poses a serious threat to the health and performance of dairy cows. This study investigated the in vitro cytotoxicity of DON on bovine mammary epithelial cells (MAC-T). DON at different concentrations (0.25, 0.3, 0.5, 0.8, 1 or 2μg/ml) inhibited the growth of MAC-T cells after 24hr of exposure (p<.001). DON at 0.25μg/ml increased lactate dehydrogenase (LDH) leakage (p<.05); decreased glutathione (GSH) levels (p<.001), total superoxide dismutase (T-SOD) activity and total antioxidant capacity (T-AOC; p<.01); and increased malondialdehyde (MDA) concentration (p<.01) in MAC-T cells after 24hr of exposure. We also observed that DON increased reactive oxygen species (ROS) levels in cells incubated for 9, 15 and 24hr (p<.001). DON at 0.25μg/ml triggered oxidative damage in MAC-T cells. Furthermore, it induced an inflammatory response in the cells incubated for 9, 15 and 24hr (p<.05) by increasing the mRNA expression levels of nuclear factor kappa B, myeloid differentiation factor 88 (MyD88), tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, cyclooxygenase-2 and IL-8. We further examined the effect of DON on apoptosis. DON prevented normal proliferation of MAC-T cells by blocked cell cycle progression in 24hr (p<.001). In addition, the apoptosis rate measured using annexin V-FITC significantly increased (p<.05) with increase in the mRNA expression level of Bax (p<.01) and increase in the Bax/Bcl-2 ratio (p<.01) in cells incubated for 24hr. In summary, DON exerts toxic effects in MAC-T cells by causing oxidative stress, inducing an inflammatory response, affecting cell cycle and leading to apoptosis.