The effects of brown adipose-derived stem cells (BADSCs) differentiating into pacemaker cells induced by three dimensional scaffold materials were observed to provide experimental evidence for the construction of tissue engineered pacemaker in vitro.

BADSCs, cultivated for 7 days, were planted into the collagen sponge, gelatin sponge and hydrogel separately. Cell morphology changes in the cell-scaffold complex were observed with the light microscope and scanning electron microscope at different time. Immunofluorescence staining was used to detect the expression of myocardial and pacemaker cell-related protein. The values were analyzed using one-way ANOVA.

BADSCs survived and proliferated in all three kinds of scaffold. According to the LIVE/DEAD detection, the cell death rate in collagen sponges, gelatin sponges and hyaluronic acid hydrogels was (46.35±1.50) %, (47±1.60) % (1.76±1.08) %, respectively. The cells in the hyaluronic acid hydrogel had the lowest mortality (F = 37.56, P?< 0.05) , while the cell-hyaluronic acid hydrogel complex spontaneously pulsated. Two weeks after planting, the positive rate of Connexin45 cells in collagen sponges, gelatin sponges and hyaluronic acid hydrogels was (10.67±1.25) %, (13.67±1.25) %and (21±1.60) %respectively. The positive rate of HCN2 cells was (11±1.60) %, (14±2.16) % and (34.33±3.68) %, the positive rate of HCN4 cells was (18.67±2.05) %, (13±1.60) % and (66±2.94) %respectively and the positive rate of Sr cells was (13±1.63) %, (14.33±1.24) % and (75.33±3.30) %respectively. Positive rates of Connexin45, HCN2, HCN4 and Sr cells in hydrogels were significantly higher than that in collagen sponge and gelatin sponge (P < 0.05) .

BADSCs could grow and differentiate well in collagen sponges, gelatin sponges and hyaluronic acid hydrogels, and hyaluronic acid hydrogels was more suitable for the construction of tissue engineered pacemaker.