[Effects of epithelial cell conditioned medium on differentiation of BMSCs]

To investigate the feasibility of inducing canine BMSCs to differentiate into epithelial cells in vitro with epithelial cell conditioned medium (ECCM).

Five mL BMSCs were obtained from iliac spine of a healthy adult male canine with weighing 10 kg, and then isolated and cultured. The oral mucosa was harvested and cut into 4 mm x 4 mm after the submucosa tissue was eliminated; ECCM was prepared. BMSCs of the 2nd passage were cultured and divided into two groups, cultured in ECCM as experimental group and in L-DMEM as control group. The cell morphological characteristics were observed and the cell growth curves of two groups were drawn by the continual cell counting. The cells were identified by immunohistochemical staining through detecting cytokeratin 19 (CK-19) and anti-cytokeratin AE1/AE3 on the 21st day of induction. The ultra-structure characteristics were observed under transmission electron microscope.

The cells of two groups showed long-fusiform in shape and distributed uniformly under inverted phase contrast microscope. The cell growth curves of two groups presented S type. The cell growth curve of the experimental group was right shifted, showing cell proliferation inhibition in ECCM. The result of immunohistochemical staining for CK-19 and anti-cytokeratin AE1/AE3 was positive in the experimental group, confirming the epithelial phenotype of the cells; while the result was negative in the control group. The cells were characterized by tight junction under transmission electron microscope.

The canine ECCM can induce allogenic BMSCs to differentiate into epithelial cells in vitro.