e0077 Effect of pulsed alternating microcurrentstimulation on communication junction function of cocultured rat mesenchymal stem cells and cardiac muscle cells

Objective This study was to investigate the effect of pulsed alternating micro-current (PAMC) stimulation on the communication junction function of co-cultured rat mesenchymal stem cells (MSCs) and cardiac muscle cells by simulating the physiological electrical environment for cardiac muscle cell growth. Methods Healthy SD rat bone marrow was subjected to 5-azacytidine induced culture. MSCs not induced (IPAMC) and MSCs cultured for 7 (IIPAMC), 14 (IIIPAMC), and 28 days (IVPAMC) after induction were co-cultured with Hoechst33258 labelled cardiac muscle cells, and stimulated with PAMC. Morphological changes in the gap junction were observed, and the following parameters were determined in each group: intracellular Cx43 distribution and content, the function of intercellular junction communication, the intracellular free calcium concentration and CaMKII expression levels. The results were also compared with those of the group not treated with PAMC. Results There was a number of typical gap junction structures in group IIIPAMC. Compared to the groups not subjected to PAMC stimulation, group IIIPAMC showed a greater increase in the Cx43 expression (78.59±6.72 vs 66.48±9.69, p<0.01), the highest fluorescence recovery rate after photobleaching in the co-culture cells (50.25%±4.08% vs 45.89%±3.94%, p<0.05), an increase in [Ca2+]i (101.21±11.36 vs 96.97±9.71, p>0.05), and a significant enhancement of the CaMKII expression (734.35±20.16 vs 596.32±13.45, p<0.01). Conclusions Appropriate PAMC stimulation will effectively promote the formation of typical intercellular gap junction structures, increase and accelerate the synthesis of gap junction protein, and enhance the intercellular communication junction function.