Increase in voltage gated potassium currents of human lymphocytes on culture

587-590Voltage gated potassium channels present in T lymphocytes play an important role during lymphocyte activation. Though an increase in potassium currents has been reported in activated lymphocytes, changes in potassium currents in culture without activation by antigen or mitogen has not been reported. The peak potassium current densities on day 1 and day 5 of culture have been compared in this study. Peripheral blood mononuclear cells (PBMCs) were separated by density gradient centrifugation. Lymphocytes were separated from PBMCs by negative selection using anti-CD14 coated magnetic beads and cultured under appropriate conditions without antigenic or mitogenic stimulation. Lymphocytes were patched on day 1 or day 5 of culture. Voltage gated potassium currents were recorded by whole cell patch clamp technique using a depolarizing protocol. The mean of peak current densities recorded at +60 mV on day 1 of culture was 228.12± 89.39 pA/pF (n=7) and on day 5 of culture was 468.96 ± 192.07 pA/pF (n=7). The difference between the current densities on day 1 and day 5 was found to be significant. Change in electrophysiological characteristics can lead to functional changes in the lymphocytes and this should be considered when culturing lymphocytes in vitro for research and clinical use

An electrophysiological comparison of freshly isolated caprine articular chondrocytes versus cryopreserved chondrocytes

Objectives: Cryopreserved chondrocytes find numerous applications in reconstructive surgery, tissue engineering, and cell-based therapy. Cryopreserved chondrocytes may behave differently due to a change in cell biology. To assess phenotype maintenance, the electrophysiological profile of the cells can be studied. In this study, a comparison between freshly isolated and cryopreserved chondrocytes was made by recording ionic currents using patch clamp. Materials and Methods: Caprine articular chondrocytes were harvested and cryopreserved for 7–15 days and divided into two groups. Percentage cell viability was assessed, following which both fresh and cryopreserved cells were subjected to analysis in whole cell configuration using depolarizing voltage steps. Results: Outwardly, rectifying currents were recorded in both groups. Comparison of current densities at all potentials above the threshold, revealed no significant difference between fresh and cryopreserved chondrocytes. Conclusion: As electrophysiological properties of cryopreserved chondrocytes appear to be maintained, they may be readily utilized in place of fresh cells. </jats:sec