Induction of vascular endothelial growth factor after application of mechanical stress to retinal pigment epithelium of the rat in vitro.

PURPOSE

To investigate the response to mechanical stress of vascular endothelial growth factor (VEGF) production by cultured retinal pigment epithelial (RPE) cells.

METHODS

A pulsatile stretch device was used in vitro. RPE cells of the second passage were seeded onto flexible-bottomed culture plates; then, at subconfluent culture, the plates were subjected to pulsatile stretch. Culture plates prepared in the same way but not subjected to stretch were used as controls. After stretching for 1 hour or 24 hours, conditioned medium for measurement of VEGF production by RPE cells was collected using a mouse VEGF immunoassay. To study the expression of VEGF in RPE cells, passaged-cultured RPE cells were exposed to pulsatile stretch for 0, 1, 3, or 14 hours. Total cytoplasmic RNA was then prepared from the RPE cells. Northern blot analysis was performed for VEGF, with G3PDH used as an internal control.

RESULTS

The expression and secretion of VEGF in RPE cells were increased by pulsatile stretching.

CONCLUSIONS

Results indicate that stretching of the RPE could result in increased production of VEGF, with associated risk for neovascularization and changes in the blood-retinal barrier.