Protective Effects Of Resveratrol On Oxidative Damage Of Neurons Induced By Benzo(a) Pyrene Exposure From Birth To Adolescence In Rats

Objective: Benzo[a]pyrene(Benzo [a] pyrene,B [a] P)is a widespread chemical pollutant in the environment and a representative substance of polycyclic aromatic hydrocarbons.The human body can be exposed to benzo[a]pyrene in a variety of ways,including the burning of fossil fuels,cigarette smoke,charcoal grilled foods and so on.Compared with the carcinogenicity of benzo[a]pyrene,there are much fewer studies on its neurotoxicity.Exposure to benzo[a]pyrene is associated with learning and memory impairment and neurodevelopmental disorders in human beings.At present,the reported molecular mechanisms of neurotoxicity of benzo[a]pyrene are as follows: effects of benzo[a]pyrene on neurotransmitters and their metabolites,disruption of brain biochemistry,change of related genes,especially NMDAR gene expression,destruction of redox balance and oxidative stress.Timely removal of oxidation products produced by benzo[a]pyrene and restoration of the balance of antioxidant system are of great significance to prevent or reduce the neurotoxicity of benzo[a]pyrene.Resveratrol is a natural polyphenol compound found in a variety of fruits,plants and related products,such as red wine.It has been shown to have a variety of health-promoting effects,including the prevention and / or treatment of cardiovascular disease,inflammation,diabetes,neurodegeneration,aging and cancer.As a direct antioxidant,resveratrol can scavenge a variety of ROS/RNS and secondary organic free radicals,thus protecting cell biomolecules from oxidative damage.Resveratrol can also enhance the expression of various antioxidant defense enzymes,such as superoxide dismutase,to maintain cell redox balance.This defense can be achieved by regulating a variety of signal pathways such as SIRT1.In this study,a model of benzo[a]pyrene poisoning was established in developing Wistar rats.Focusing on the oxidative damage of nerve cells induced by benzo[a]pyrene,we explored the specific molecular mechanism of resveratrol in reducing the oxidative damage of benzo[a]pyrene,and provided experimental evidence for the study of the mechanism of neurotoxicity induced by benzo[a]pyrene.Methods: Healthy adult female and male Wistar rats were obtained from Experimental Animal Center of China Medical University,The temperature in the laboratory animal room is 17-23℃,and the relative humidity is 45-55%.Forty-nine pups born to pregnant rats were randomly divided into 7 groups with 7 pups in each group according to the ratio of female to male of 1:2 in a cage.The following experiments were conducted from the 5th day after birth to the age of 7 weeks.All of them were treated by gastric gavage.The first group was treated with corn oil as control group.The second group was low B [a] P group,the dose was 1 mg/kg B [a] P,the third group was medium B [a] P group,the dose was 2 mg/kg B [a] P,the fourth group was high B [a] P group,the dose was 4 mg/kg B [a] P,the fifth group was resveratrol(RSV)control group,the dose was 30 mg/kg.The sixth group was treated with low-dose resveratrol(RSV)for 4 hours,followed by 4 mg/kg B [a] P,and the seventh group was treated with high-dose resveratrol(RSV),followed by 4 mg/kg B[a] P after 4 hours of 30 mg/kg RSV.The corresponding indexes were detected after exposure.The behavioral changes of rats were evaluated by open field test,step-down test and Morris water maze test.Apoptosis and ROS,were detected by flow cytometry.The mRNA expression of MnSOD in neurons was detected by RT-q PCR.The expression of SIRT1,FOXO3 a,and MnSOD protein was detected by Western blot.The acetylation level of FOXO3 a protein was detected by immunoprecipitation method.The binding of FOXO3 a protein and MnSOD promoter was detected by chromatin immunoprecipitation method.Results: Exposure to benzo[a]pyrene from 5 days after birth to seven weeks old will lead to abnormal neurobehavioral changes in rats.The open field test showed that the average speed and stay time in the central area of 4 mg/kg high dose benzo[a]pyrene exposure group were significantly lower than those of the control group,and the results of step down test and Morris water maze test showed that the learning and memory ability of 4 mg/kg high dose benzo[a]pyrene exposure group was impaired,which indicated that the neurotoxicity model of Wistar rats had been successfully established.Compared with the control group,the production of ROS,the activity of MnSOD,the level of MDA and the apoptosis of neurons in the 1 、 2 、 4 mg/kg benzo[a]pyrene group were significantly increased,and the mRNA expression of MnSOD in the 2 mg/kg benzo[a]pyrene group was significantly higher than that in the control group.Compared with the control group,the expression of SIRT1 and FOXO3 a protein increased,the expression of MnSOD protein decreased,the activity of SIRT1 deacetylase decreased and the acetylation level of FOXO3 a protein increased significantly in 4 mg/kg high dose benzo[a]pyrene group.Chromatin immunoprecipitation test showed that the binding ability of FOXO3 a protein to MnSOD promoter decreased in 4mg/kg high dose benzo[a]pyrene group.Compared with 4 mg/kg high-dose benzo[a]pyrene group,30 mg/kg resveratrol intervention can improve neurobehavioral performance,alleviate apoptosis,activate SIRT1-FOXO3 a pathway and reduce oxidative damage induced by benzo[a]pyrene.Conclusion: Benzo pyrene can induce oxidative damage of nerve cells in Wistar rats;resveratrol has antioxidant effect,which can reduce oxidative damage through SIRT1-FOXO3 a pathway and reduce the toxic effect of benzo[a]pyrene on nerve cells.