Figure 7.

Channels exist for MSCs and fluid to traverse between the right and left pleural cavities. Only a few seconds after methylene blue injection into the right side pleural cavity, blue fluid was found flowing into the left thorax (A), indicating that there were quick fluid channels that permitted fluid to pass through the mediastinum. Likewise, DAPI-labeled MSCs suspension was also injected into the right side pleural cavity, fluorescence cells were easily visualized in the fluid flowing into left thorax under fluorescence microscopy (B). Both images of DAPI-stained (C) and normal mediastinal pleura (D) demonstrated that there were many oval stomas of different sizes in the cell monolayer part of mediastinal pleura (white arrows), indicating that these may be the unidentified anatomical channels by which fluid and cells traverse between the two pleural cavities freely. (B–D), ×100.