Inquiry Into The Change Of CD4~ + CD25~ + Foxp3~ + Regulatory T Cells With Aging And The Relation With The Lung Tumor

Objective To explore the relationship and mechanisms between the change of CD4~+CD25~+Foxp3~+ regulatory T cells (regulatory T cells, Treg) with aging and the lung tumor.Methods To set up Lewis lung cancer model with C57BL/6 female mice. 36 mice were divided into young health, middle-aged health, elderly health, young tumor, middle-aged tumor and elderly tumor. We evaluated the change of CD4~+CD25~+Foxp3~+Treg in spleen of six groups by Flow cytometry method and the level of Foxp3 mRNA in splenocyte by Real-time RT-PCR method.Results 1.Tumors were observed after inoculated lung cancer cell. However, there were significant difference both in the volume and the weight of tumor among different groups, which were more increased in the elderly tumor than the other two groups. 2.The level of CD4~+CD25~+Foxp3~+ / CD4~+ T cells (t=2.23,P=0.032)and the quantity of Foxp3 mRNA(t=3.26,P=0.0042)were higher in tumor than in healthy group. Besides, in the healthy groups, there were statistical difference among the three groups(F=47.70,P=0.000). Accumulation of the CD4~+CD25~+Foxp3~+ Treg was accompanied with aging, the elderly mice contained a significantly larger population of CD4~+CD25~+Foxp3~+ Treg in their spleen when compared with the younger counterparts, So it was with the functional gene Foxp3 mRNA(F=6.56,P=0.0090). 3.Among the six groups, the highest of the CD4~+CD25~+Foxp3~+ Treg and the functional gene Foxp3 mRNA was the elderly tumor group.Conclusions Many mechanisms involved in the aging process share molecular ways implicated in carcinogenesis processes. The accumulation of CD4~+CD25~+Foxp3~+ Treg with aging may be described as a mainly reason for the elder's susceptibility to the tumor.