The Inhibitory Effect Of EGCG On PC12 Cells Damage Induced By Methylglyoxal And Advanced Glycation End Products

Methylglyoxal(MGO)is derived from abnormal glycolysis and food,which is a precursor of advanced glycation end products(AGEs).MGO can form AGEs by non-enzymatic reaction with proteins,lipids or nucleic acids,which can be obtained through diet or produced in the body.The accumulation of MGO and AGEs in the human body is involved in the development of various pathologies,such as neurodegenerative diseases,diabetes,atherosclerosis and cardiovascular diseases.With the increasing incidence of aging of the population,neurodegenerative diseases have become a global health problem.Inhibition of MGO and AGEs-induced neurotoxicity may be a potential treatment for neurodegenerative diseases.Epigallocatechin gallate(EGCG)is mainly derived from green tea and has various activities such as antioxidant,anti-inflammatory,anti-tumor and so on.However,whether EGCG can inhibit the neurotoxicity induced by MGO,AGEs and the generation of AGEs needs further investigation.Rat adrenal pheochromocytoma cell(PC12)were used as model to test whether EGCG can inhibit PC12 cells damage induced by MGO and AGEs.The MTT method was used to determine the safe concentration of EGCG and the damage concentration of MGO and AGEs.PC12 cells were pretreated with different concentrations of EGCG to detect the inhibitory effect of EGCG on the decline of cell viability induced by MGO and AGEs.DCFH-DA,Rh123 and Hoechst 33258 assay were used to detect ROS,mitochondrial membrane potential and apoptosis levels,respectively.Western blot experiments were performed to detect the expression of glyoxalase I(GLO 1)and the receptor of advanced glycation endproducts(RAGE)proteins,p38 MAPK,JNK,apoptotic proteins,NF-?B and ERK/CREB/BDNF pathways,which elucidated the possible protective mechanism of EGCG.At the same time,the MGO-bovine serum albumin(BSA)system was established,and the effects of EGCG on the inhibition of AGEs induced by MGO were explored by fluorescence spectrum,UV-visible spectroscopy,circular dichroism and molecular docking experiments.The results show that 2.5-50 ?M EGCG can not cause cell loss.After treatment with MGO and AGEs,it can reduce cell survival,increase ROS,reduce mitochondrial membrane potential,and promote apoptosis,10,20,and 40 ?M EGCG pre-treatment can reverse this situation.EGCG may play a neuroprotective role by regulating the expression of GLO 1,RAGE,Bax,Bcl-2,CytC,and Cleaved Caspase-3,inhibiting p38 MAPK,JNK,NF-?B signaling pathways,and activating the ERK/CREB/BDNF signaling pathway.Therefore,EGCG can inhibit PC12 cells cytotoxicity induced by MGO and AGEs.The results of fluorescence spectrum and circular dichroism chromatography showed that EGCG could stabilize the secondary structure of BSA and inhibit the generation of AGEs.The results of molecular docking proved that EGCG occupied BSA's arginine and formed 3 hydrogen bonds with BSA,which inhibited the generation of AGEs.In summary,EGCG can not only inhibit PC12 cells damage induced by MGO,but also inhibit the generation of AGEs,which has a certain protective effect on PC12 cells damage induced by AGEs.This study may provide a certain theoretical and experimental basis for the prevention and treatment of neurotoxicity caused by MGO,AGEs,and provides a reference for the in-depth study and reasonable utilization of EGCG.