The Effect Of Titanium Ions On The Membrane Potential And Kv1.3 Channel In T-Lymphocytes

Objective:To study the effect of titanium ions on intracellular concentration of dissociative calcium ion, cell membrane potential and Kvl.3 channel in T-lymphocytes and to investigate the influence of titanium ions on the cell proliferation of T-lymphocytes.Methods:l.Jurkat T-lymphocytes were cultured in vitro and exposed to TiCl4.MTT assay was performed to detect the concentration and of titanium ions that enhance the maximum proliferation of T-lymphocytes.2.T-lymphocytes were cultured with and without phytohemagglutinin (PHA) preactived divided into four groups (different dosages),in the presence of 0μmol/L,25μmol/L,50μmol/L and 100μmol/L titanium ions for 24h.The change of intracellular Ca2+ concentration and cell membrane were analyze the by flow cytometry.The expression of Kvl.3 mRNA was detected by real-time fluorescent quantitative RT-PCR.The change of intracellular Ca2+ concentration and cell membrane after titanium treatment were also observed either with or without Ca2+ outside of the cells.Results:1.These experiments revealed a concentration-dependent,enhanced proliferative response to titanium ions challenge with a maximum of average activity at a 100μmol/L concentration(P<0.05).With increasing the titanium ions concentrations, there were corresponding and significant decreases in the proliferation rates of T-lymphocytes.2.Different dosages of titanium ions(25μM/L,50μM/L,100μM/L) can induce the depolarization of membrane potential of preactivated and non-preactivated T-lymphocytes with and without outside Ca2+.Compare with the control group,the difference was statistically significant (p<0.05).The difference of different dosages showed statistically significant (p<0.05) in preactived T-lymphocytes.The difference of different dosages was not statistically significant (p>0.05) in non-preactived T-lymphocytes without outside Ca2+.3.After treated with different dosages of titanium ions(25μM/L,50μ M/L,100μM/L), the intracellular Ca2+ concentration of preactived and non-preactived T-lymphocytes were increased with outside Ca2+(p<0.05,versus control group).While without Ca2+ outside the cell,the intracellular Ca2+ concentration of preactived T-lymphocytes treated with different dosages of titanium ions were higher than the control group (p<0.05).But there was not statistically significant (p>0.05) in different dosages groups when compare with control group in non-preactived T-lymphocytes.4. When cultured with different dosages of titanium ions(25μM/L,50μ M/L,100 μM/L) for 24h,the expression of Kv1.3mRNA were increased gradually in the preactived T-lymphocytes.There were significantly difference compared with control group(p<0.05).Medium and High dosages titanium ions(50 μ/L,100μM/L) induced the expression of Kvl.3mRNA higher than the control group(p<0.05) in non-preactived T-lymphocytes,while the low dosage of titanium ions showed no statistical difference(p>0.05).Conclusions:1.Titanium ions can enhance the proliferation of T-lymphocyte in a certain concentration (0-100μmol/L)2.Titanium ions(25μM/L,50μM/L,100 μM/L) can induce the depolarization of cell membrane potential, rise the concentration of the intracellular Ca2+ by promoting the inflow of outside Ca2+ and increase the expression of Kvl.3 mRNA of T-lymphocytes.3.There is more significant effect of titanium ions on the membrane potential and Kv1.3 channel in preactived T-lymphocytes.