[Primary culture and identification of rat glomerular podocytes]

To establish an easy and feasible method for primary culture and identification of rat glomerular podocytes.

Glomeruli from Sprague-Dawley (SD) rats weighing 60-100 gram were isolated by the method of different size combination of screen. Isolated glomeruli were appropriately digested with 2 g/L type IV collagenase and cultured in 25 cm2 plastic flask coated with rat tail collagen in K1-3T3 medium with ITS-X (containing insulin-transferrin-selenium). Subculture of primary cultured epithelial cells was performed at 9-10 days after implantation of collagenase digested glomeruli. Podocytes were identified by the morphology study with scanning electron microscope and inverted microscope, as well as the immunohistochemistry staining (SP methods) study for the expression of keratin, desmin and Wilms' tumor suppressor-1 (WT-1).

Epithelial cells outgrowth from isolated glomeruli appeared after 3 days primary culture and grew to confluence with cobblestone-appearance at 9-10 days. These cobblestone cells were subcultured at this point and gradually conversed into large, flat arborized cells with well-developed processes and microvilli. These arborized cells were negative expression with desmin staining and showed positive expression of cytokeratin and WT-1, which indicated that they were podocytes.

Implantating collagenase digested-glomeruli is an easy and feasible method for primary culture of rat glomerular podocytes. WT-1 may serve as a good marker to identify rat glomerular podocytes.