Effects of retinoic acid and TGF-beta 1 on the proliferation and melanin synthesis in chick retinal pigment epithelial cells in vitro.
OBJECTIVE
The purpose of this study was to investigate the effects of all-trans retinoic acid (RA) and transforming growth factor-beta 1 (TGF-beta 1) on proliferation and melanin synthesis of chick retinal pigment epithelial (RPE) cells in vitro.


METHODS
Chick RPE cells were cultured in the presence or absence of RA (10(-5) to 10(-7) M) or TGF-beta 1 (1 to 100 U/ml) for a 10-day period. The effects of RA and TGF-beta 1 on RPE cell proliferation were assessed by counting the number of cells, and their effects on melanin synthesis were evaluated by measuring the melanin content in the cells.


RESULTS
RA significantly inhibited RPE cell proliferation in a time-dependent manner. The most marked inhibition was observed on day 10 of culture, and the most effective concentration of RA was 10(-6) M. Melanin synthesis was increased on day 10, and the most effective concentration of RA was also 10(-6) M. TGF-beta 1 also inhibited RPE cell proliferation and increased melanin synthesis.


CONCLUSIONS
These findings indicate that RA and TGF-beta 1 have regulatory effects on the proliferation and differentiation of chick RPE cells in vitro.
Kishi
H
H
Department of Ophthalmology, Hiroshima Mitsubishi Hospital, Japan. hmh05@hdsnet.co.jp
Mishima
H K
HK
Yamashita
U
U
D000818:Animals; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002642:Chick Embryo; D008543:Melanins / Q000096:biosynthesis*; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014212:Tretinoin / Q000494:pharmacology*
D008543:Melanins; D016212:Transforming Growth Factor beta; D014212:Tretinoin