Scleral cell growth is influenced by retinal pigment epithelium in vitro.

Abstract

Studies of form-deprivation myopia in chicks have shown that mitotic activity and the amounts of DNA and protein are increased in the sclera of myopic eyes. Signals acting on the sclera have been speculated to have their origin in the retina, especially in the photoreceptors and the retinal pigment epithelium (RPE). Therefore, in this study we investigated the interaction between the RPE cells and the scleral cells in vitro using chick embryo. At first, we established the method for primary culture of scleral chondrocytes and scleral fibroblasts from chick embryos. Then, we co-cultured scleral chondrocytes with RPE cells and also co-cultured scleral fibroblasts with RPE cells. Scleral cells were cultured on a collagen membrane or Transwell-COL, with RPE cells cultured at the bottom of the dishes. We evaluated the effects of co-cultured RPE cells on the proliferation of scleral cells by counting the cell number of scleral cells on those membranes. With the co-cultured RPE cells, proliferation of the scleral chondrocytes was inhibited on a collagen membrane, but significantly stimulated on a Transwell-COL. Proliferation of the scleral fibroblasts was also promoted on the Transwell-COL with RPE cells. RPE cells influenced the proliferation of scleral cells in vitro, which suggests that RPE may, at least in part, act on the sclera in vivo to regulate ocular growth postnatally.