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 2 μg/ml) inhibited the growth of MAC‐T cells after 24 hr of exposure (p < .001). DON at 0.25 μg/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 24 hr of exposure. We also observed that DON increased reactive oxygen species (ROS) levels in cells incubated for 9, 15 and 24 hr (p < .001). DON at 0.25 μg/ml triggered oxidative damage in MAC‐T cells. Furthermore, it induced an inflammatory response in the cells incubated for 9, 15 and 24 hr (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 24 hr (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 24 hr. 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.

Impact of Mycotoxins on Animals’ Oxidative Status

“…Regarding the in vitro studies, a recent work by Pauletto et al [93] on bovine hepatocytes reported a significant increase in MDA concentration in incubated cells with AFB1, while their transcriptional profile of antioxidant enzymes (CAT, SOD, GSH-Px) were not affected. Two comparable studies conducted in vitro in bovine mammary epithelia cells that were treated with DON (0.25 µg/mL) for 24 h showed an increase in the concentration of MDA while TAC and GSH portrayed a decrease [94,95]. More specifically, Wang et al [94] reported a lower activity of the SOD enzyme and Zhang et al [95] observed the same trend in transcript levels (SOD1 and SOD2).…”

“…Two comparable studies conducted in vitro in bovine mammary epithelia cells that were treated with DON (0.25 µg/mL) for 24 h showed an increase in the concentration of MDA while TAC and GSH portrayed a decrease [94,95]. More specifically, Wang et al [94] reported a lower activity of the SOD enzyme and Zhang et al [95] observed the same trend in transcript levels (SOD1 and SOD2). In both experimental trials, despite the negative oxidative status that was observed, immunomodulating genes related to pro-inflammatory responses were reported in higher expression levels, suggesting a cytokine storm.…”

The Protective Effect of Heme Oxygenase-1 on Liver Injury Caused by DON-Induced Oxidative Stress and Cytotoxicity

“…However, as the dose and time of DON exposure increase, the redox balance may be disrupted. For example, 0.25 μg/mL DON can cause a decrease in total superoxide dismutase (T-SOD) activity and glutathione (GSH) levels and increase reactive oxygen species (ROS) and malondialdehyde (MDA) levels [ 10 ]. When the diet of mice was contaminated with DON, the activities of CAT and SOD in the liver decreased, while the content of MDA increased [ 11 ].…”

Susceptibility of Oocytes from Gilts and Sows to Beauvericin and Deoxynivalenol and Its Relationship with Oxidative Stress

“…Possibly, in gilts, this was a compensatory mechanism due to the low GSS expression in mature oocytes. Both DON [ 50 ] and BEA [ 51 ] induce oxidative stress and also decrease the capacity to synthesize GSH, partly explaining the high susceptibility of gilt COCs to these mycotoxins during maturation.…”