Experimental diabetes attenuates calcium mobilization and proliferative response in splenic lymphocytes from mice

Abstract

The present study was conducted to investigate the effects of the diabetic condition on cytosolic free Ca2+ concentration, [Ca 2+]i, and the proliferation of splenic lymphocytes from mice. Diabetes was induced in mice by intraperitoneal injection of alloxan. [Ca2+]i and the proliferation ex vivo of splenic lymphocytes isolated from mice were examined using fura-2 and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide, respectively. Diabetes caused a significant increase in resting [Ca2+]i and significantly reduced the ability of concanavalin A (Con A; a T-lymphocyte-selective mitogen) to increase [Ca2+]i, but not that of lipopolysaccharide (LPS; a B-lymphocyte-selective mitogen). In addition, diabetes significantly reduced Con A-stimulated but not LPS-stimulated lymphocyte proliferation. Verapamil (an L-type Ca2+ channel blocker) inhibited Con A-induced increases in [Ca2+]i and proliferation in lymphocytes from control and diabetic mice to a similar extent, respectively. These results suggest that diabetes attenuates Con A-stimulated T-lymphocyte proliferation by decreasing [Ca2+]i via reduction of Ca2+ entry through L-type Ca2+ channels. © 2010 The Physiological Society of Japan and Springer.