Analysis of the effect of Rhodopseudomonas palustris on the lead exposure rat model using 1H-NMR-based metabolomics of urine and plasma

Background Rhodopseudomonas palustris had the effect of adsorbing and removing lead ions. Metabolomics is a comprehensive analysis based on several metabolites or biomarkers. Objective The paper aimed to investigate the restorative effect and the potential mechanisms of R. palustris in rats with the lead exposure model using H-1-NMR metabolomics. Results Nine endogenous metabolites from rat plasma and 13 endogenous metabolites from rat urine were identified as potential biomarkers of the symptoms of lead poisoning. The changes of metabolites levels in the plasma included lower levels of valine, acetoacetate, and N-acetyl-glycoprotein and a higher concentration of lactate, acetate, creatine, threonine, glutamine, and asparagine in model group compared with control group. Furthermore, increased citrate, succinate, dimethylamine, pyruvate, acetoacetate, alpha-oxoglutarate and asparagine, accompanied by decreased LDL/VLDL, taurine, creatinine, glucose and hippurate levels were observed in the model group compared with the control group in the urine. Biochemical parameters and histopathology examination dovetailed well with the metabolomics data. Treatment with R. palustris at a certain degree returned the levels of these metabolites to normal levels. Plasma and urine metabolomic analysis showed changes associated with energy metabolism, amino acids and fatty acid metabolism of lead exposure rats. Conclusion The effects of removing lead ions of R. palustris in rats with lead exposure were confirmed. This research demonstrated that H-1-NMR-based metabolomics was a promising tool to identify potential biomarkers and unravel protective effect mechanisms of R. palustris in lead poisoning rats.