“Kidney and urinary metabolic profiles of monosodium glutamate consumption in Wistar rats”

Abstract

While its effects on human health are still debated, monosodium glutamate (MSG) has been widely used globally for at least five decades. Since there are no reliable biomarkers of MSG consumption in human, the monitoring of harmful effects of MSG intake on human health is not feasible. We aim to investigate the kidney and urinary metabolic profiles of MSG consumption in animals. Adult male Wistar rats were assigned into 4 groups, including receiving water with 1 g% MSG added, 0.34 g% NaCl added, 2.4 g% NaHCO3 and normal drinking water. Urine chemistries were analyzed before and after 2 weeks of MSG‐treatment. Urinary metabolic profile was determined after MSG supplementation using NMR technique. Kidney tissue were also investigated for ion‐exchanger genes expression including its metabolites. The results revealed that the MSG‐ and alkaline‐treated groups had significantly higher levels of urine pH, urine sodium and bicarbonate compared to controls. This corresponds to the lower expression of ion‐exchanger genes (CAII, NBC1, and AE1) involved in bicarbonate reabsorption in kidney of MSG‐ and alkaline‐treated groups compared to controls. The kidney metabolic profile of MSG and control groups were also investigated. We found that trimethylamine had significantly higher level in MSG group, whereas the higher levels of pyridoxine found in controls. In conclusion, MSG‐treated rats are able to induce alkaline urine, reduce bicarbonate reabsorption and generate the urinary metabolic profiles similar to that of alkali supplemented animals. Moreover, the urinary and kidney metabolomics revealed that there is a connection between the uremic toxin and MSG consumption in rats.Support or Funding InformationThe Royal Golden Jubilee Ph.D. Program (RGJ‐Ph.D. Program) (PHD/0124/2558). The Invitation research fund (IN62137), Faculty of Medicine, Khon Kaen University, Thailand.