RESUMEN
<p><b>OBJECTIVE</b>To observe the effect of the costimulatory molecules CD137 and CD28 on Bcl-2 expression in T cells of mice with D-galactose-induced aging and natural aging.</p><p><b>METHODS</b>Seven-week-old male BALB/c mice were injected daily with D-galactose (120 mg/kg) for 5 months to induce subacute aging, and 16-month-old male BALB/c mice served as the natural aging group. The spleen T cells of were isolated from the rats and stimulated in vitro with conA+IgG, conA+CD137 mAb or conA+CD28 mAb for 48 h. Bcl-2 expression of T cells was detected by flow cytometry and semi-quantitative RT-PCR.</p><p><b>RESULTS</b>In the subacute aging group, Bcl-2 protein expression rate in the T cells stimulated with conA+IgG, conA+CD137 mAb and conA+CD28 mAb were (24.4-/+1.5)%, (34.4-/+2.4) %, and (45.1-/+2.7) %, which were (19.6-/+2.0) %, (26.3-/+1.9) %, and (48.5-/+2.2) % in the natural aging group, respectively. In vitro stimulation with conA+IgG, conA+CD137 mAb and conA+CD28 mAb resulted in expression rate of bcl-2 mRNA in the T cells of 0.309-/+0.039, 0.547-/+0.036, and 0.780-/+0.041 in the subacute aging group, and 0.283-/+0.038, 0.535-/+0.041, and 0.771-/+0.063 in the natural aging group, respectively.</p><p><b>CONCLUSION</b>CD137 and CD28 can promote bcl-2 expression at both mRNA and protein level in T cells in aging mice, which may be one of the mechanisms through which CD137 and CD28 molecules inhibit aging T cell apoptosis and maintain their function.</p>