PI3K/Akt/mTOR Signaling Pathway Expression In Occupational Aluminum-exposed Workers With Cognitive Impairment And Its Mechanism In Zebrafish

Objective: 1.Evaluate the effect of aluminum exposure on the cognitive function of workers exposed to aluminum.Observe the expression of PI3K/Akt/m TOR signal pathway,and its relationship with aluminum-induced cognitive impairment.2.The m TOR inhibitor rapamycin was used as a model of cognitive impairment of zebrafish exposed to aluminum,and the role of PI3K/Akt/m TOR signaling pathway in aluminum-induced cognitive impairment was explored.Methods: 1.Epidemiological study: the method of cluster sampling was selected,and 1869 workers in Shanxi Aluminum Plant were selected as the research object.The workers in the electrolytic aluminum workshop were selected as the exposure group,and the workers in the thermoelectric workshop and the logistics department were the control group.(1)general demographic data such as employee age,marital status,monthly average income level,education level,smoking,drinking,occupational history,disease history,etc.were collected,and neuropsychological questionnaire of MMSE and CDT texts was used to evaluate the cognitive function.(2)The biological sample of the worker was collected,and the concentration of Al in the blood was measured by ICP-MS.(3)The expression levels of PI3 K,Caspase9,FADD,TNF,AKT,Caspase3,Caspase8,RIPK and m TOR were detected by RT-PCR.2.zebrafish experiment: 8 months old adult zebrafish were selected for experiment,randomly divided into 4 groups(25 per group)exposed for 30 days: control group(rapamycin 0 ?g/L,aluminum trichloride 0 ?g/L),aluminum trichloride group(aluminum trichloride 200 ?g/L),rapamycin group(200 ?g/L),rapamycin plus aluminum trichloride group(rapamycin 200 ?g/L,aluminum trichloride 200 ?g/L).(1)T labyrinth behavior experiment: the zebrafish T-maze device established a nutrient-rich(EC)region at the end of the short arm,and the latency of the zebrafish into the EC region and the cumulative residence time of the EC region was evaluated to virified the learning and memory skills.(2)The expression level of PI3 K / Akt / m TOR signaling pathway related genes was measured by RT-PCR method.(3)The expression level of PI3 K / Akt / m TOR signaling pathway related protein was measured by ELISA.(4)HE staining and Nissl staining were used to observe the cell number and pathological changes of brain tissue.Results: 1.The concentration of Al in the exposed group was higher than that in the control group.Compared with the control group,the expression of PI3 K,AKT and m TOR in the exposed group was significantly decreased(P <0.05).Age,educational level,aluminum concentration in blood,and m TOR expression levels was major factors which influenced the score of neuropsychological testing of MMSE and CDT.The concentration of aluminum in the blood,age with MMSE scores were negatively correlated.The educational level,m TOR expression levels were positively correlated with MMSE scores.The scores of MMSE and CDT would be decreased as the blood aluminum concentration was increased,and the Akt expression level would be decreased as the worker's blood aluminum concentration was increased by the model of RCS.Akt was involved as mediator to the correlation between aluminum concentration and cognitive function test(MMSE,CDT score).2.Zebrafish behavioral experiments indicated that the latency in the aluminum trichloride group,the rapamycin group,and the aluminum trichloride plus rapamycin group was prolonged compared with the zebrafish in the control group,with statistical difference(P=0.000);The cumulative residence time were increased in the aluminum trichloride group,the rapamycin group,and the aluminum trichloride plus rapamycin group,compared with the zebrafish in the control group.After staining,the number of cells in the zebrafish brain tissue of the aluminum chloride group,the aluminum chloride plus rapamycin group was decreased,the cell volume was increased,the cells were aggregated and coagulated,the nuclei were deeply stained,and multiple cell debris were observed.The results of RT-PCR gene detection indicated that the expressions of m TOR,AKT1,AKT2,PI3 K,AMPK and ULK1 in the aluminum trichloride group,rapamycin group,rapamycin plus aluminum trichloride group were lower than those in the control group(P <0.05).The m TOR1 and PI3 K protein contents in the aluminum trichloride group,rapamycin,rapamycin plus aluminum trichloride groups were lower than those in the control group(P <0.05).Conclusion: Long-term exposure to aluminum could lead to the impairment of cognitive.Neuropsychological testing of MMSE,CDT could be used as a clinical assessment of cognitive function testing.Long-term exposure to aluminum could cause the blood aluminum levels was increased in the body.PI3 K / Akt / m TOR signaling-related genes were involved in the process of aluminum-induced cognitive changes,and cell death was one of the mechanisms of aluminum-induced neurotoxicity.PI3 K / Akt / m TOR signaling pathway was involved in aluminum-induced neuronal cell death.