Metabolomics Study Of Cadmium Poisoning Rats Based On UPLC/Q-tof MS

Objective:UPLC/Q-tof MS was used to analyze the metabolic profile of urine in cadmiumpoisoned rats,and the metabolic markers in the urine of cadmium-intoxicated rats were screened and identified to provide a basis for exploring the metabolic mechanism of cadmium and early diagnosis of cadmium poisoning.Methods:One rat was housed in each metabolic cage,a total of four groups,16 in each group,8 males and 8 females.The control group was intragastrically administrated with equal volume of distilled water.The three experimental groups were intragastrically administrated with different doses of cadmium chloride solution.The rats were subjected to a 30-day feeding experiment,and urine samples on day 28 were collected for metabolomics analysis.Detection and screening of metabolic markers: All samples were pretreated and subjected to UPLC/Q-tof MS for metabolic profiling.The clustering of metabolic profiles was analyzed by PCA,PLS-DA and OPLS-DA.The screening conditions include CV>30,VIP>1,P<0.05,and max fold change≥2.Identification and pathway analysis of metabolic markers: The allowable error of primary and secondary mass spectra is required to be <5ppm in the identification,the matching database is Serum,HMDB,LIPD MAPS,and the final mass spectrometry identification score >50 is considered successful.Path analysis was performed using the MetaboAnalyst platform.Results:At the same time,the body weight of the four groups of rats was different,and the body weight of the rats showed a downward trend with the increase of cadmium intake dose.The weights of the organs,liver,spleen,kidney and testis were different in the weight of the four groups of rats,and the weight of the organs in the high dose group was generally lower than that of the control group.In this experiment,after analyzing the urine metabolites of cadmium-intoxicated rats,14 different metabolites were obtained,which were3-Sialyl-N-acetyllactosamine,N-Acetylglutamine,4-(2-Amino-3-hydroxyphenyl)-2,4-dioxobutanoate,Dethiobiotin,3,4-DihydroxyphenylglycolO-sulfate,Chondroitin,3-Hydroxydodecanedioic acid,12-Ketodeoxycholic acid,Norepinephrine,L-Dopa,L-Phenylalanine,L-2-Amino-3-oxobutanoate,4,6-Dihydroxyquinoline,20-Hydroxy-leukotriene B4.Among them,Chondroitin was the difference substance between the control group and the low-and medium-dose groups;L-2-Amino-3-oxobutanoate was the difference substance between the control group and the middle and high dose groups;20-Hydroxy-Leukotriene B4 is a differential substance compared with the control group and the low dose group in the high-dose group;4,6-Dihydroxyquinoline is the difference substance in the control group,the low-dose group,the middle-dose group,and the high-dose group.Pathological search was performed using the MetaboAnalyst metabolic pathway search platform.The results showed that two metabolic pathways were statistically significant(P<0.05).Pathway 1 is the tryptophan metabolism pathway,and pathway 2 is the phenylalanine,tryptophan and tyrosine biosynthetic metabolic pathways.Conclusion:1.A total of 14 potential biomarkers were detected by UPLC/Q-tof MS in the comparison of different doses of cadmium intake group.2.Chondroitin may be a biomarker of early cadmium poisoning.L-2-Amino-3-oxobutanoate,4,6-Dihydroxyquinoline and 20-Hydroxy-Leukotriene B4 may be moderate to severe cadmium poisoning.Biomarkers.3.Cadmium poisoning may have an effect on the body and the tryptophan metabolism pathway and the biosynthetic metabolic pathways of phenylalanine,tyrosine and tryptophan.