Protective Effect Of Lycopene On Oxidative Stress Injury In Mammary Gland Of Dairy Cows

The increased metabolic demand of dairy cows during the perinatal period is accompanied by an increase in oxidative stress,which in turn increases the incidence of udder inflammatory response and reduces cow production performance and body health.Lycopene(LYC)is a class of active substances extracted from tomatoes,which has the effect of regulating oxidative stress and inflammation.The role of lycopene in alleviating oxidative stress-induced udder inflammation were explored in this study.(Method)In vivo test method:One hundred pre-perinatal dairy cows with similar body weights,milk yields in the previous parity and parity were divided into 2 groups.The healthy cows were fed the basal diet(no LYC;n=50),and the mastitis cows were fed the basal diet rich in lycopene(LYC:5g/head/d;n=50).The experimental period was from 21 d before parturition to 21 d after parturition,of which the pre-feeding period was from 21 d before parturition to the day of calving,and the normal feeding period was from the day of calving to 21 d after parturition.According to the changes in the external characteristics of the udders of dairy cows from 2d to 10d postpartum,10 cows with mastitis were selected from the control group(n=10)and the lycopene-treated group(n=10)as the follow-up experimental animals.Blood and milk were collected from cows in the mastitis group and LYC+mastitis group on the 7th,14th and 21st days after calving,respectively.In vitro test method:bovine mammary epithelial cells(BMECs)were first incubated with or without 2μM LYC for 12 h,and then incubated with or without 600μM hydrogen peroxide(H2O2)for 6h to construct Con,H2O2,LYC and LYC+H2O2.(Results)The results of the in vivo study found that lycopene significantly increased milk production,blood glucose concentration,superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)activities in mastitis cows;significantly reduced somatic cell count(SCC)in milk,blood levels ofβ-hydroxybutyrate(BHBA),free fatty acids,cholesterol,triglycerides,reactive oxygen species(ROS),malondialdehyde(MDA),aspartate aminotransferase,alanine aminotransferase and glutamyl transpeptide activity,pro-inflammatory factors tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),interleukin-2(IL-2),interleukin-6(IL-6)and interleukin-8(IL-8)content.In vitro studies found that H2O2 increased intracellular ROS levels and pro-inflammatory factors,and induced cells to produce oxidative damage,inflammatory damage and apoptosis;lycopene enhanced the survival rate of BMECs by activating the protein expression of the nuclear factor erythroid 2-related factor 2(NFE2L2)/heme oxygenase-1(HMOX-1)pathway,scavenging intracellular ROS and pro-inflammatory factors.(Conclusion)Lycopene can improve the production performance and health status of mastitis cows by reducing the oxidative stress and inflammatory response.The mechanism is that lycopene activates the NFE2L2/HMOX-1 pathway and inhibits ROS/TNF-α pathway to alleviate oxidative damage,inflammatory damage and apoptosis.This study revealed the effect and mechanism of lycopene in alleviating oxidative stress mastitis,and provided a theoretical basis and technical support for lycopene to effectively alleviate oxidative stress-induced mastitis.