Figure 6.

Confirmation of heterocellular coupling for cardiomyocyte (CM) and cardiac fibroblasts (CF) in the spheroidal droplets. Heterocellular coupling between CM (green) and CF (red) is shown after 7 and 14 days of culture (a–d). % of heterocellular coupling is depicted using a bar graph in (e). The extent of coupling was found to be significantly greater in the 3D spheroidal droplets (p < 0.03) compared to the controls after 7 days of culture. Immunocytochemical data for CM-CF coculture at 7 days demonstrated the presence of CM and CF as analyzed by cell marker troponin I for CM and FSP for CF and imaged as shown in (e). Scale bar in all images is 100 μm. Furthermore, Western blot analysis demonstrated an increase in Trp-I expression in the spheroidal droplets compared to the controls, p < 0.05. Trp-I bands for protein expression are depicted along with a row of β-actin that was used as a housekeeping control protein. Bands were obtained by running 25 μg of protein, and membrane was developed using 1 min exposure.