Effect Of Melatonin On T Cell Activation In Gastric Tumor-Bearing Mice Mediated By NF-?B And MAPK Pathways

Melatonin is a neuroendocrine hormone that is primarily synthesized by the pineal gland and is involved in the regulation of body immunity?metabolism and circadian rhythms.Melatonin plays an important role in the regulation of tumorigenesis and development of tumors,but its immunoregulatory effects and mechanisms on gastric cancer have not been clarified yet.The purpose of this study was to establish pinealectomy and gastric tumor-bearing mouse model and to investigate the immunoregulatory mechanism of gastric tumor-bearing mice after melatonin intervention by flow cytometry,Real time RT-PCR,Western Blot and immunohistochemistry.Paraffin section and HE staining showed that the pinealectomy and stomach tumor-bearing mouse models were successfully constructed.Flow cytometry results showed that the expression levels of CD4,CD26,CD69,CD278,and I-A/I-E were significantly down-regulated in 10 and 20 mg/kg of melatonin,while the CD38 expression was down-regulated and the expression levels of CD8 a and Granzyme B were up-regulated in mouse splenocytes at 10 mg/kg of melatonin.The expression of CD38 in spleen cells of 20 mg/kg group was up-regulated and the expression of Granzyme B and perforin were down-regulated.The expression of CD4,CD8 a,CD26,CD38,Granzyme B,I-A/I-E and perforin were up-regulated and the expression of CD69 was down-regulated in splenocytes of 40 mg/kg of melatonin.Cytometric Bead Array results showed the levels of IFN-?,TNF,IL-2,IL-4,IL-6 and IL-10 in plasma of mice at 10 mg/kg dose were down-regulated,TNF,IL-6 and IL-10 in plasma of 40 mg/kg mice were up-regulated.Real time PCR results showed that in the thymus tissue,the expression level of NF-?B mRNA was down-regulated in the 10 mg/kg dose group.The expression levels of Elk-1,JNK,NF-?B and p38 mRNA were up-regulated in the 20 mg/kg dose.In spleen tissues,the expression levels of Elk-1,LAT,and p38 mRNA were up-regulated in the 10 mg/kg dose.Western Blot results showed that in the thymus tissue,the expression of p-JNK protein was up-regulated and the expression of LAT,NF-?B,and p38 protein were down-regulated in the 10 mg/kg of melatonin.The expression of Elk-1 and NF-?B protein were up-regulated in the 20 mg/kg dose.The expression of Elk-1,LAT,NF-?B,and p38 protein were down-regulated in the 40 mg/kg dose.In the spleen tissues,the expression of Elk-1 and p38 protein were down-regulated and the expression of p-JNK and NF-?B protein were up-regulated in the 10 mg/kg of melatonin.The expression of p-JNK and LAT protein were up-regulated in the 20 mg/kg dose.The expression of Elk-1 protein was down-regulated and the expression of LAT,NF-?B,and p38 protein were up-regulated in the 40 mg/kg dose.In gastric tissue,p-JNK protein expression was up-regulated in the 10 mg/kg of melatonin.The expression of p-JNK protein was down-regulated in the 20 mg/kg dose.The expression of Elk-1 protein was up-regulated while the expression of p-JNK and LAT protein were down-regulated in the 40 mg/kg dose.The immunohistochemistry results showed the expression of p38 was down-regulated and the expression of ERK1/2 was up-regulated in 10 mg/kg dose of melatonin,the expression of p-JNK?LAT?ERK1/2 were upregulated in 20 mg/kg dose,the expression of LAT was down-regulated in 40 mg/kg dose.Conclusion:NF-?B and MAPK signaling pathways mediate the activation of T cells with melatonin intervention in gastric tumor-bearing mice.