Apigenin Attenuates Patulin-induced Apoptosis In HEK293 Cells By Modulating Oxidative Phosphorylation And Caspase Signal Pathway

Mycotoxins like patulin(PAT)are among the most significant food contaminant with regard to public health,and both oxidative stress and mitochondrial dysfunction play vital roles in PAT toxicity.Apigenin(API)is one of the most bioactive flavonoids in plant-derived food,API is considered to be a phytoestrogen and has been shown to exhibit a variety of biological properties,including anti-inflammatory,antioxidant,anticancer,antiproliferative,hepatoprotective,renoprotective and neuroprotective.However,studies on API protecting cells or bodies against the deleterious effects of foodstuff contaminants are quite limited.The present study which employed HEK293 cells as an in vitro model,was designed to elucidate the protective effects of API on the cell damage and apoptosis caused by PAT and the possible underlying mechanisms.Cells were treated under basic conditions(control),8 ?M PAT without or with API(2.5,5 and 10 ?M)for 10 h.API was added concomitantly with PAT.Results are as follows:(1)Cell viability decreased to 71.4% when cells exposed 8 ?M PAT for 10 h.A significant LDH leakage in culture media was also observed after PAT treatment.While API alone exhibit no cytotoxic effects in the concentration range tested(0-10 ?M),cell co-treatment with different concentration of API showed ameliorate effect against PAT induced mortality in a concentration-dependent manner(P < 0.01).(2)API exerted its renoprotective effect against PAT cytotoxicity by modulating mitochondrial dysfunction and oxidative phosphorylation.API could inhibit PAT-induced intracellular reactive oxygen species(ROS)accumulation to balance intracellular redox levels.API re-established mitochondrial membrane potential(MMP)to maintain mitochondrial membrane integrity and block the cytochrome c release.Moreover,API could modulate oxidative phosphorylation especially elevating the expression of complex I,complex II and ATP synthase and maintain higher intracellular ATP level to protect mitochondria functioning well.(3)The alleviated effect of API against PAT toxicity was accompanied by downregulation of p53 expression,thus reduced Bax level while elevated Bcl-2 expression.Thereby,the release of cytochrome c from mitochondria to cytoplasm was reduced,resulting in the inhibition of initiator caspases-9,and executioner caspases(3,6 and 7)expression andenzyme activities in a dose-dependent manner.What's more,API also inhibited the activities and expression of caspase-2 and caspase-8 via the extrinsic pathway of apoptosis to protect HEK293 cells against apoptosis.