Cytocompatibility of silk fibroin film with rabbit urinary bladder transitional epithelial cells in vitro

Objective To obtain large quantities of well differentiated urinary bladder transitional epithelial cells for used as the seed cells in bladder tissue engineering, and evaluate the cytocompatibility of silk fibroin film with the transitional cells in vitro to assess the possibility of tissue-engineered urinary organ construction. Methods The urinary bladder transitional epithelial cells were isolated from the bladders of New Zealand rabbits and cultured in vitro as the seed cells, whose morphology was observed and the specific protein (cytokeratin) expression identified by immunofluorescence assay. The cells were seeded in 96-well plates at 1×104/ml and incubated with silk fibroin film leaching solution or culture medium (negative control). MTT assay was performed to determine the cell proliferation rates of the wells and evaluate the cytotoxicity and cytocompatibility of the silk fibroin film. Results The isolated urinary bladder transitional epithelial cells reached confluence after 9-10 days of culture, which showed positive staining for immunocytochemistry with monoclonal antibody against cytokeratin. The absorbance of the cells culture in the presence of silk fibroin film leaching solution averaged 0.424±0.020, 0.996±0.118 and 1.285±0.048 after at 24, 72 and 120 h of cell culture, and that of the negative control group at the time points was 0.419±0.030, 1.105±0.098 and 1.228±0.052, respectively, showing no significant difference between the two groups (P0.05). Conclusion Silk fibroin film has good cytocompatibility with rabbit urinary bladder transitional epithelial cells, and may serve as good scaffold material for urologic tissue engineering.