Effects Of Taraxasterol To Alleviate The Deoxynivalenol-induced Injure Of Bovine Mammary Epithelial Cells

Deoxynivalenol,which is generally referred to as DON,has many biological effects.This substance plays a negative role in biochemical reactions.Even the residual part,if eaten by livestock and poultry,will cause a strong vomiting reaction.Due to this phenomenon,it is usually called vomitoxin.If there’s vomitoxin intake during animal feeding,the toxin residue will eventually enter the human body through the food chain.Therefore,this material also has certain harm to human beings.Vomitoxin is a kind of toxin produced by Fusarium,which can cause great pollution to crops and residue in animal’s feed,leading to great losses to livestock and poultry economy every year.In this study,bovine mammary epithelial cells were used to establish a model to investigate the damage of vomitoxin,so as to study the potential harm of vomitoxin on dairy farming,and explore feasible protection schemes by studying its microscopic mechanism.In the study of chemical constituents of taraxacum,it was found that taraxasterol was one of its components.The effective activity of taraxasterol is relatively high,and it has many beneficial effects on human beings.It has been proved to have anti-inflammatory,antioxidant,antitumor and other beneficial effects in medicine.In this experiment,the concentration of vomitoxin was first screened.Bovine mammary epithelial cells were treated with different concentrations of vomitoxin(0.05,0.1,0.2,0.3 and 0.5 μg/m L)for 24 h,the cell viability was detected afterwards.The results showed that when the concentration of vomitoxin was greater than or equal to0.2 μg/m L,the damage effect on bovine mammary epithelial cells was obvious,and the cell viability was significantly reduced.Therefore,0.2 μg/m L vomitoxin was selected for subsequent experiments.The results showed that the content of lactate dehydrogenase(LDH)detected in the cell solution increased significantly after the cells were treated with 0.2 μg/m L of vomitoxin for 24 h.Vomiting toxin can significantly reduce the antioxidant capacity of bovine mammary epithelial cells and induce oxidative stress in bovine mammary epithelial cells,resulting in a significant decrease in glutathione(GSH)level,a significant decrease in superoxide dismutase(T-SOD)level,an increase in lipid peroxide(MDA)content,and a decrease in total antioxidant capacity(T-AOC).Vomitoxin can significantly increase the content of reactive oxygen species(ROS)in bovine mammary epithelial cells.After verifying the inhibitory effects of vomitoxin on cell viability and antioxidant capacity of bovine mammary epithelial cells,the protective effect of taraxasterol was studied by adding the combination of taraxasterol and vomitoxin.Firstly,bovine mammary epithelial cells were treated with taraxasterol(0.5,1,5,10 and 20 μg/m L)for 24 h to detect cell viability.The results showed that when the concentration of taraxasterol was in the range of 1–10 μg/m L,the activity of bovine mammary epithelial cells was significantly increased.Taraxasterol and vomitoxin(0.2 μg/m L)were combined to treat bovine mammary epithelial cells for 24 h to test cell viability.The results showed that taraxasterol at the concentration of 10 μg/m L could effectively reduce the damage of vomiting toxin.Therefore,0.2 μg/m L vomitoxin and 10 μg/m L taraxasterol were selected in the subsequent experiments to explore the protective effect of taraxasterol.The results showed that taraxasterol can effectively alleviate the oxidative stress and the decrease of cell antioxidant capacity caused by vomitoxin,reduce the MDA content of bovine mammary epithelial cells,increase the levels of GSH and T-SOD,recover the total antioxidant capacity(T-AOC)and reduce the release of LDH.The cells in each treatment group were observed under the fluorescence inverted microscope.The green fluorescence intensity of the taraxasterol treatment group was significantly lower than that of the vomiting toxin treatment group,and the ratio of the red fluorescence intensity to the green fluorescence intensity,which represent the level of mitochondrial membrane potential,was significantly increased,indicating that taraxasterol had a protective effect on the injury of bovine mammary epithelial cells caused by vomitoxin.In order to explore the damage mechanism of vomitoxin on bovine mammary epithelial cells,this study explored the changes in the expression of related genes in endoplasmic reticulum stress signaling pathway and apoptosis signaling pathway of bovine mammary epithelial cells after treated with vomitoxin and taraxasterol.The results showed that the m RNA and protein expressions of GRP78,ATF4,ATF6 and CHOP were significantly up-regulated by vomitoxin in endoplasmic reticulum stress signaling pathway,while the expressions of these genes were significantly down-regulated after treated with taraxasterol.Vomitoxin can significantly up-regulate the m RNA and protein expression of BAX and caspase-3 in the apoptotic signaling pathway,downregulate the m RNA and protein expression of Bcl-2,and promote the cell apoptosis.Taraxasterol can inhibit the expression of BAX and caspase-3 and promote the expression of Bcl-2,which plays a role in inhibiting apoptosis.