The Mitigation Mechanism Of Allicin On Acrylamide-induced Oxidative Stress And Endoplasmic Reticulum Stress In Rat BRL-3A Cells

Acrylamide(AA)is a common food contaminant formed during heat processing that has neurotoxicity,reproductive toxicity,hepatotoxicity,genetic toxicity and potential carcinogenicity.Oxidative stress and endoplasmic reticulum stress(ERS)and related pathways may contribute to one of the toxic mechanisms of AA.Allicin is the main biologically active ingredient in garlic,which physiological functions such as antioxidant,liver protection,and neuroprotection have been proven.In this paper,we aim to explore the mechanism of AA-induced rat BRL-3A hepatocyte injury,and then by adding natural botanic allicin,to investigate its protective effect on oxidative stress-and ERS-mediated apoptosis induced by AA,thereby laying the research foundation for further development of allicin.The main results and conclusions were made as follows:(1)The effect of allicin on the oxidative stress damage index of AA-induced rat BRL-3A hepatocytes was investigated.The results showed that AA could significantly increase the level of ROS in rat BRL-3A cells,reduce the activities of SOD and GSH-Px,and increase the level of DNA damage factor 8-OHd G.However,allicin reduced the intracellular ROS and 8-OHd G levels and restored the activities of SOD and GSH-Px in AA-induced cells,indicating that allicin could be a good ROS scavenger for rat BRL-3A cells,increase cell's antioxidant capacity,enhance cell viability and improve AA-induced oxidative stress damage.Besides,allicin could protect rat BRL-3A cells from AA-induced oxidative stress damage by inhibiting the expression of CYP2E1.The mechanism of action may be that allicin binded to the amino acid residues of CYP2E1(Phe116,Phe207,Leu210,Phe298,Ala299,Thr303,Val364,and Phe478)through hydrophobic interactions,reduced CYP2E1 activity,and thereby inhibiting cytotoxicity caused by AA.(2)The effect of allicin on the expression of MAPK pathway and related proteins in AA-induced rat BRL-3A hepatocytes was researched.The results showed thatallicin could significantly down-regulate the phosphorylation levels of JNK and p38,and up-regulate the phosphorylation level of ERK.Besides,NAC could inhibit the phosphorylation levels of MAPK key proteins,indicating that the induction of excessive ROS production by AA could activate MAPK pathway,and then trigger cell biological response.Allicin could inhibit JNK and p38 pathways,activate ERK pathway,and play a protective role in AA-induced oxidative stress in rat BRL-3A cells.Allicin could reverse the changes of Phospholipase A2,KGF,Gadd45 a,c-Fos,and Dusp5 expression in rat BRL-3A cells induced by AA,and regulate these MAPK pathway-related proteins,thereby interfering with AA-induced liver cell damage.Besides,we make the following guesses:(1)Allicin may regulate the expression of KGF protein in MAPK pathway to repair damaged cells and inhibit apoptosis.(2)Allicin might mediate the MAPK pathway to inhibit c-Fos expression,and the MAPK pathway was regulated by Dusp5 to a certain extent.(3)Allicin might down-regulate the expression of Gadd45 a and up-regulate the expression of Phospholipase A2.And it could improve the antioxidant capacity,and reduce AA-induced oxidative damage.(3)The effect of allicin on ERS-mediated apoptosis induced by AA in rat BRL-3A hepatocytes was explored.The results showed that allicin significantly down-regulated the expression of GRP78,CHOP and cleaved caspase-12,and inhibited the activation of IRE1,TRAF2,ASK1 and JNK in AA-induced rat BRL-3A cells.It was suggested that allicin could inhibit the IRE1 pathway and thus regulate the MAPK pathway by inhibiting JNK activation,reduce the ratio of Bax/Bcl-2,maintaine intracellular Ca2+ homeostasis,and through the downstream caspase cascade reaction interactions,which collectively played a protective role in AA-induced ERS-mediated apoptosis.In summary,allicin can be a good ROS scavenger for rat BRL-3A hepatocytes,increase antioxidant capacity,enhance cell viability,and improve oxidative stress injury.Allicin also protects rat BRL-3A cells from oxidative stress by inhibiting the JNK and p38 pathways and activating the ERK pathway.In addition,allicin can regulate the MAPK pathway by inhibiting the IRE1 pathway,reduce the ratio of Bax/Bcl-2 in rat BRL-3A cells,thereby maintaining the intracellular Ca2+ dynamic balance,and jointly interfere with ERS-mediated apoptosis induced by AA through the interaction of downstream caspase cascade reactions.This thesis can provide areliable theoretical basis for the use of natural plant-derived antioxidants to alleviate the hazard of food processing contaminant such as AA to the body or animal models in the future.