RESUMEN
BACKGROUND: Studies have shown that bone marrow mesenchymal stem cells have the potential of differentiation into alveolar epithelial cells in vitro, but so far no study has indicated that adipose-derived mesenchymal stem cells (ADSCs) can be differentiated into alveolar epithelial cells through long-term Transwell co-culture. OBJECTIVE: To observe whether rat lung epithelial-T-antigen negative cell lines (RLE-6TN) can induce rat ADSCs to differentiate into type II alveolar epithelial cells by long-term Transwell co-culture. METHODS: Three SPF health female Sprague-Dawley rats were used as donors to separate, extract, culture and identity ADSCs. The experimental group was subjected to the Transwell co-culture of ADSCs and RLE-6TN, while the control group was subjected to the culture of ADSCs alone. The morphological changes of ADSCs were observed by the inverted phase contrast microscope at 21 days after co-culture. Immunofluorescence staining using surfactant protein C (SP-C) was performed on the co-cultured ADSCs. The fluorescence staining was observed using the inverted fluorescence microscope. Integral optical density (IOD) analysis was conducted by Image pro plus 6.0 software. RESULTS AND CONCLUSION: RLE-6TN cells were identified by fluorescence staining with stable expression of SP-C protein (red fluorescence) in the experimental group, and there was no red fluorescence in the control group. After 21-day co-culture, the cell shape in the experimental group was transformed from the long spindle shape into oval or polygon shape gradually, while the cell shape in the control group remained fibroblast-like. These results show that RLE-6TN can induce ADSCs to differentiate into type II alveolar epithelial cells after a long-term (21 days) co-culture.