Abstract:

Objective To investigate the effect of melatonin(MLT) on the expression of type Th1/Th2/Th17 cytokines such as interferon(IFN)-γ, tumor necrosis factor(TNF), interleukin(IL)-2,IL-4,IL-6,IL-10,IL-17a and so on of gastric cancer in vitro and in vivo. Methods 1. Model of gastric cancer-bearing mice was established. Then 32 male 615 mice were all inoculated with murine foregastric carcinoma cells and randomly divided into 4 groups, and injected intraperitoneally with melatonin at doses of 0, 25, 50 and 100 mg/kg, and measureed long and short diameter of tumor, respectively. After a week of intervention, peripheral blood was taken and the tumor tissue was removed for weighing and measurement. 2. Murine foregastric carcinoma (MFC)cells were inoculated into a six-well cell culture plate and routinely cultured. After 24 hours of adherence, they were treated with melatonin at different concentrations of 0, 2, 4, 6, 8 and 10 mmol/L. After 24 hours again, the cells morpology were observed and the corresponding supernatants were collected. 3. The expressions of melatonin concentrations in peripheral blood serum was detected by enzyme -linked imm unosorbent assay (ELISA). The expressions of Th1/Th2/Th17 cytokines in peripheral blood serum and cell supernatants were detected by cytometric bead array (CBA) respectively. Results 1. Tumor-bearing mice models were successfully established. Compared with the negative control group, the melatonin concentration in peripheral blood serum of the middle and high dose MLT group which increased significantly, and the tumor volume significantly decreased. Compared with the negative control group, the concentration of IL-10 in the middle dose group increased significantly. And the concentration of IFN-γ, IL-2 and IL-10 in the high dose group increased significantly too. 2. Compared with the 0 mmol/L MLT group, the concentrations of IFN-γ in the 6 and 10 mmol/L MLT group were significantly decreased; the concentrations of IL-6 in the 4, 6, 8 and 10 mmol/L MLT group were significantly decreased, and the concentration of IL-10 in 6 mmol/L MLT group was significantly increased. All the difference were statistically significant (P<0.05). Conclusion Melatonin inhibits the proliferation of murine foregastric carcinoma cell MFC both in vitro and in vivo, and may enhance tumor immunity by adjust the expression of IFN-γ, IL-2, IL-6 and IL-10 cytokines of type Th1/Th2/Th17 cells.

Key words: Melatonin, Gastric cancer, Th1/Th2/Th17 cytokines, Cytometric bead array, Mouse