Aim: To develop a method to deliver mesenchymal stem cells (MSCs) into the pleural cavity for the treatment of pleural diseases.
Methods: MSCs were isolated from rat bone marrow of rats and labeled with 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) or green fluorescent protein (GFP) using a lentiviral vector. Eighteen Sprague-Dawley (SD) rats were inoculated intrapleurally with 1×10(6) MSCs-DAPI. The distribution of the fluorescent cells was observed using fluorescent microscopy for the following 30 d. Another 12 rats inoculated intrapleurally with 1×10(6) MSCs-GFP were observed for 14 d.
Results: The isolated cells were typical MSC phenotypes and could differentiate into adipocytes, osteoblasts, and chondroblasts in vitro. Microscopic analysis revealed that the labeled cells adhered to the surface of the pleural cavity. The highest number of the labeled cells was found to be adhered to all specimens from the mediastinal pleura, but no labeled cells were detected in the lung parenchyma or other tissues/organs, such as the liver, kidney, spleen, and mesenterium. Incidentally, stomas were found in the mediastinal pleura. The recovered MSCs-GFP from the pleural cavity retained their ability to adhere and proliferate.
Conclusion: We have established a novel method for intrapleural delivery of MSCs. The distribution of intrapleurally delivered MSCs was found to be limited to the pleurae and the pleural cavity, thereby providing us with a new approach to further investigation of the therapeutic roles of MSCs in pleural diseases.