This study aims to explore the mechanism of Liujunzi Decoction in the treatment of 4-nitroquinoline-N-oxide(4NQO)-induced esophageal cancer in mice. One hundred mice of 35-45 days were randomized into blank, model, and low-, medium-, and high-concentration(18.2, 36.4, and 54.6 g·kg~(-1), respectively) Liujunzi Decoction groups. The mice in other groups except the blank group had free access to the water containing 100 μg·mL~(-1) 4NQO for 16 weeks for the modeling of esophageal cancer. The mice in the Liujunzi Decoction groups were fed with the diets supplemented with corresponding concentrations of Liujunzi Decoction. The body weight and organ weights were weighed for the calculation of organ indexes. The pathological changes of the esophageal tissue were observed by hematoxylin-eosin(HE) staining. Ultra performance liquid chromatography-mass spectrometry(UPLC-MS/MS) was employed to collect metabolites from mouse serum samples, screen out potential biomarkers, and predict related metabolic pathways. Compared with the blank group, the model group showed decreased spleen and stomach indexes and increased lung, esophagus, and kidney indexes. Compared with the model group, Liujunzi Decoction groups had no significant changes in the organ indexes. The HE staining results showed that Liujunzi Decoction inhibited the invasive growth and cancerization of the esophageal cancer cells. A total of 9 potential biomarkers of Liujunzi Decoction in treating esophageal cancer were screened out in this study, which were urocanic acid, 1-oleoylglycerophosphoserine, 11-deoxy prostaglandin E1, Leu-Glu-Lys-Glu,(±) 4-hydroxy-5E,7Z,10Z,13Z,16Z,19Z-docosahexaenoic acid, ureidosuccinic acid,(2R)-2,4-dihydroxy-3,3-dimethylbutanoic acid, kynurenic acid, and bicyclo prostaglandin E2, which were mainly involved in histidine, pyrimidine, alanine, aspartate, glutamate, pantothenate and tryptophan metabolism and coenzyme A biosynthesis. In summary, Liujunzi Decoction may exert the therapeutic effect on the 4NQO-induced esophageal cancer in mice by regu-lating the amino acid metabolism, inflammation, and immune function.
Keywords: 4-nitroquinoline-N-oxide; Liujunzi Decoction; esophageal cancer; serum metabonomics.