ABSTRACT
The development of eye is a very dynamic process in which various cells and tissues from diverse originneuroectoderm, surface ectoderm and mesenchyme, undergo induction, mitosis and differentiation. During this process advances, many growth factors are involved. Transforming growth factor betas (TGF-betas) are the pivotal growth factors during cellular growth, differentiation, matrix formation, migration and wound healing. Especially during the development of tissues, TGF-beta s are secreted and induce growth and differentiation of adjacent cells. To investigate the functions of TGF-betas during the development of eye, we studied the expression of TGF-betas in rat embryos. For this study, Sprague-Dawley rat embryos were taken on the 11th 13th, 15th, 17th and 19th day of gestation. To confirm the morphological changes of eyes on each developmental stage, sections were stained with hematoxylin and eosin. Then, to document the expressive patterns of TGF-beta1, beta2, beta3 and TGF-beta receptor type II (TbetaR), immunohistochemistry was applied. The results were obtained as follows: TGF-beta1 was partially expressed in the lens only on the 19th day of gestation. TGF-beta2 was expressed in the retina and lens on the 11th and 13th day, while it was detected in most areas of the eye from the 15th to 19th day. TGF-beta3 was expressed only in the pigment cell layer of the retina on the 11th day, but it was detected in various areas along the advance of the development. Immunoreactivity of TGF-beta3 was always weaker than TGF-beta2. TbetaR showed strong immunoreactivity in where the reactivity of TGF-beta2 was detected. These results indicate that TGF-beta2 and beta3 play important roles during the development of eye.