钛离子对T淋巴细胞体外增殖及活化的影响

Effects of titanium ions on the proliferation and activation of T lymphocytes in vitro

BACKGROUND: Titanium ions have been proved to stimulate the secretion of bone remodeling-related factors from T lymphocytes; however, the effects of titanium ions on the early activation, intermediate activation, and cell cycle of T lymphocytes remain unclear. OBJECTIVE: To investigate the effects of titanium ions on the proliferation and activation of T lymphocytes in vitro. METHODS: Cell proliferation and cycle test: Jurkat E6-1 T lymphocytes in logarithmic phase were collected and cultured in the medium containing 0 (control), 25 (low concentration), 50 (middle concentration), and 100 μmol/L (high concentration) titanium ions for 24 hours to detect the cell relative proliferation rate and cell cycle. Cell activation trial: Jurkat E6-1 T lymphocytes were divided into two groups that were subdivided into four groups containing 0, 25, 50, and 100 μmol/L titanium ions, respectively with or without phytohemagglutinin (PHA) pre-stimulation. The expressions of CD69 and CD25 were measured after cultured for 24 hours. RESULTS AND CONCLUSION: Titanium ions enhanced T lymphocytes proliferation in a concentration-dependent manner (P < 0.05). Compared with the control group, the percentages of G₀/G₁ phase decreased and the proportions of cells in S and G2/M phase increased significantly in the low, middle and high concentration groups (P < 0.05). The proportion of G₀/G₁-phase cells in the high concentration group was less and the proportion of G₂/M phase cells was higher than those in the middle and low concentration groups (P < 0.05). With PHA pre-stimulation, the expression of CD69 in the high concentration group was higher than that in the middle and low concentration groups (P < 0.05); whereas the difference of CD25 expression was not significant among four subgroups. Titanium ions promoted the expression of CD69 in a concentration-dependent manner (P < 0.05), but there was no CD25 expression in each subgroup without PHA pre-stimulation. To conclude, titanium ions can significantly promote T lymphocyte proliferation and early activation in vitro, and moreover, induce S and G₂/M phase arrest in T lymphocytes.