The Protective Effect Of Melatonin Against Inflammation Injury Of Bovine Mammary Epithelial Cells Induced By Lipopolysaccharide

The mastitis is one of the biggest diseases that harm the dairy farming industry,and it can cause serious economic losses.Mammary epithelial cells that are in direct contact with the outside world and are important immune cells against pathogens.Melatonin(MLT)is secreted by the pineal gland and has a wide range of physiological effects.It is also an effective free radical scavenger and antioxidant.In this study,the mammary gland epithelial cells MAC-T was used as the research object.The model of bovine mammary epithelial cell inflammation was induced by lipopolysaccharide(LPS).The cell viability was detected by MTT assay.The inflammatory factor signal was detected by real-time PCR and the MTT was induced by LPS.The protective effect of inflammatory injury of bovine mammary epithelial cells provides a theoretical basis for screening for effective treatment of mastitis drugs.1.The effect of LPS on MAC-T cell viability is related to time and concentration.The results of MTT showed that there was no significant change in cell viability of MAC-T cells treated with different concentrations of LPS for 12 h.MAC-T cells were treated for 24 h.The concentration of LPS was 100 μg/m L,which significantly increased cell viability.LPS significantly inhibited cells at a concentration of 400 μg/m L.Viability,LPS cells at 48 h,LPS concentrations of 200μg / m L,250μg / m L,300μg / m L,400μg / m L significantly inhibited cell viability,LPS cells for 72 h,all concentrations of LPS can inhibit cell viability.2.The establishment of an inflammation model of bovine mammary epithelial cells LPS-treated cells with LPS concentration of(50,100,150,200,250)μg/m L were treated for 12 h,and the expression levels of inflammatory factors IL-6 and IL-8 m RNA were detected by real-time PCR.All concentrations of LPS could significantly increase the expression level of m RNA.When the concentration of LPS was 100μg/m L,the expression levels of IL-6 and IL-8 m RNA were the highest,so we chose 100μg/m L to treat cells for 12 h.Conditions of the mastitis model.3.The effect of MLT on LPS-induced damage of bovine mammary epithelial cells According to the MTT method,MLT can increase the activity of MAC-T cells at concentrations of 50 μM/L,100 μM/L,150 μM/L,and 200 μM/L,and 100 μM/L and 200 μM/L can significantly increase cell viability.The results of real-time PCR showed that 50μM/L and 100μM/L could significantly down-regulate the expression of inflammatory factors IL-6 and IL-8,and down-regulate the expression of TLR4 and NF-κBp50,the key factors of TLR4/NF-κB signaling pathway.