OBJECTIVETo investigate the influence of glucocorticoid on phenotype of thymic dendritic cells in mice and to investigate the protective effect of Yougui Pill (YGP) on it.

METHODSBALB/c mice allocated in the group A and B were treated respectively with 10 mg/kg hydrocortisone, alone and combined with 20.81 g/kg YGP. The control mice were treated with normal saline. The changes before and after treatment of I-A(d) and H-2K(d) antigen presentation molecules expression in CD11c(+) and CD45(+) thymic dendritic cells of mice were analyzed by flow cytometry assay, and the expression of intercellular adhesion molecule-1 (ICAM-1) and leukocyte function-associated antigen-1 (LFA-1) mRNA in thymocytes were determined by RT-PCR as well.

RESULTSThe percentage of I-A(d+) and H-2K(d+) in CD11c(+) in Group A after treatment was 46.77 +/- 4.32% and 64.34 +/- 7.69% respectively, as compared with those in the control group (65.81 +/- 7.69% and 31.88 +/- 5.01%), the percentage of I-A(d+) was lower and that of H-2K(d+) was higher significantly (all P <0.01). Meantime, the expression of ICAM-1 and LFA-1 in thymocyte in Group A (30.11 +/- 2.51% and 30.40 +/- 3.77%) was significantly lower than that in the control group (46.35 +/- 3.34% and 47.28 +/- 2.91%) respectively (P <0.01). Changes in Group B showed that treated by hydrocortisone in combination with YGP, the above-mentioned hydrocortisone-induced changes could be obviously reversed, the outcome of CD11c(+) I-A(d+) was 54.19 +/- 5.08%, ICAM-1 33.97 +/- 2.04% and LFA-1 34.80 +/- 2.92%, the difference between the two treated groups in these indexes all showed statistical significance (P <0.05).

CONCLUSIONGlucocorticoidcan inhibit the expression of major histocompatibility complex class II antigen molecule, but promote the expression of major histocompatibility complex class I in CD11c(+) and CD45(+) dendritic cells, down-regulate ICAM-1 and LFA-1 transcription, while the tonifying yang recipe, YGP, has a dominant protective effect against the above actions of glucocorticoid.