Cell cycle arrest effects of large-dose FTY720 on lymphocytes in mouse skin transplantation models

To probe into the mechanism of immunosuppression of FTY720, the authors study the cell cycle arrest effects of large-dose FTY720 on lymphocytes in mouse skin transplantation models and the expression of cell cycle-related factors in cell cycle regulation system in mouse skin allograft models using flow cytometry, Immunohistochemical staining, and reverse transcriptase-polymerase chain reaction (RT-PCR). FTY720 could prolong survival days of graft in mouse skin transplantation models obviously (p < 0.01). In thymus gland and lymph node, compared with the control group, cell percentage in G0-G1 increases and cell percentage in G2-M and S decreases in the treated group (p < 0.01). Expression of P16 increases and expression of cyclin D1 decreases in the treated group (p < 0.05). In thymus gland, it is shown by semiquantitative RT-PCR that the quantity of mRNA of P16 increases in the treated group (p < 0.01), and the quantity of mRNA of cyclin D1 decreases in the treated group (p < 0.01). FTY720 is a kind of effective immunosuppressant. FTY720 could induce cell cycle arrest in thymus gland and lymph node and change the expression of protein and the transcription of mRNA of cell cycle-related factor.