Objective: To study the effect of Feiji Recipe (FR) intervening indoleamine 2,3-dioxygenase (IDO) induced immune escape on the murine model of Lewis lung carcinoma. Methods Totally 48 C57BL/6 mice inoculated with Lewis lung cancer cells transfected with human (enhanced green fluorescent protein,EGFP)-IDO gene were divided into four groups according to radom digit table, i.e., the model group (administered with normal saline by gastrogavage) , the Chinese medicine group (treated with FR Decoction at the daily dose of 100 mg/g by gastrogavage), the 1-methyl-D-trytaphan (1-MT) group (administered with 1-MT mixed liquor at the daily dose of 100 mg/kg by gastrogavage), and the Paclitaxel group (treated with Paclitaxel at the daily dose of 15 mg/kg by peritoneal injection), 12 in each group. The intervention was started from the 2nd day of modeling. The survival time was observed in 24 of them. Ratios of CD4+ CD25+ FoxP3+ regulatory T cells (Treg) in the spleen were detected in the rest 24 mice by flow cytometry respectively.
Results: Compared with the model group, the survival time was significantly prolonged in the Chinese medicine group and the 1-MT group (P < 0.01); ratios of Treg cells remarkably decreased in the Chinese medicine group, the 1-MT group, and the Paclitaxel group (P < 0. 01). Compared with the Paclitaxel group, the survival time was significantly prolonged in the Chinese medicine group and the 1-MT group (P < 0.01); ratios of Treg cells decreased significantly in the 1-MT group (P < 0.05).
Conclusion: FR could inhibit the proliferation of lung cancer cells and immune eseape, improve the immune function, and prolong the survival of tumor-bearing mice.