Orally Administrated Glutamate Restored EAAT1 and 3 Expression Levels Suppressed in 5-Fluorouracil-damaged Intestinal Epithelial Cells

Abstract

Background/Aim: 5-Fluorouracil (5-FU) treatment induces intestinal mucositis, with diarrhea as the primary symptom. Mucositis significantly reduces patients’ quality of life (QOL). Amino acids such as glutamate are beneficial for treating gastrointestinal disorders; however, the underlying mechanism remains unclear. Therefore, this study aimed to clarify the role of excitatory amino acid transporters (EAATs) in 5-FU-induced intestinal injury. Materials and Methods: The rat intestinal epithelial cell line (IEC-6) was used to evaluate whether the EAAT inhibitor L-trans-pyrrolidine-2,4-dicarboxylic acid (L-trans-PDC) affects 5-FU-induced cytotoxicity. Mice with 5-FU-induced mucositis were used to determine the effects of glutamate on EAATs expression levels. Results: Treatment with L-trans-PDC suppressed IEC-6 cell growth. It also exacerbated the 5-FU-induced cell growth suppression and increased inflammatory cytokine expression. In addition, mice treated with 5-FU+Glutamate showed higher EAAT1,3 expression than 5-FU only-treated mice. Conclusion: Decreased EAAT levels worsen intestinal cell damage caused by 5-FU, suppress cell growth, and induce inflammation. This study contributes to the understanding EAAT and its relationship with intestinal mucositis, which can aid in the development of novel preventive strategies for cancer chemotherapy.