Effect of topical Ginkgo biloba extract on steroid-induced changes in the trabecular meshwork and intraocular pressure.
OBJECTIVE
To study the effects of Ginkgo biloba extract (GBE) on dexamethasone (DEX)-induced ocular hypertension.


METHODS
Rabbits aged 7 weeks received topical TobraDEX (Alcon Labs, Hünenberg, Switzerland) and/or 5 microg of GBE four times daily for 14 days. Intraocular pressure (IOP) was recorded every 3 days. After enucleation, trabecular meshwork (TM) cellularity and extracellular matrix deposition were graded. The effect of GBE on apoptosis and expression of myocilin and cell stress-related genes in DEX-treated human TM cells were studied by immunofluorescence, Western blotting, and quantitative polymerase chain reaction.


RESULTS
Ginkgo biloba extract suppressed DEX-induced IOP elevation in rabbits. It reduced the DEX-associated accumulation of extracellular materials within the cribriform layers of the TM and achieved better TM cellularity. In cultured human TM cells, GBE substantially attenuated anti-Fas ligand-induced apoptosis and reduced DEX-induced myocilin expression. Ginkgo biloba extract modulated the expression of alphaB-crystallin and heat-shock proteins 70 and 90alpha but not other stress-related genes. Furthermore, changes associated with DEX were found less in GBE-treated or GBE-primed TM cells.


CONCLUSIONS
We showed that GBE, a nontoxic, antiapoptotic, herbal compound significantly suppressed steroid-induced IOP elevation in rabbits and it seems to prevent the adverse effects of DEX on TM cells.


CONCLUSIONS
Ginkgo biloba extract could be a therapeutic agent or dietary supplement to prevent steroid-induced ocular hypertension.
Jia
Li-Yun
LY
Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong, China.
Sun
Ling
L
Fan
Dorothy S P
DS
Lam
Dennis S C
DS
Pang
Chi Pui
CP
Yam
Gary H F
GH
D000287:Administration, Topical; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000235:genetics; D003907:Dexamethasone / Q000633:toxicity; D005136:Eye Proteins / Q000235:genetics; D019084:Fluorescent Antibody Technique, Indirect; D005786:Gene Expression Regulation / Q000187:drug effects; D020441:Ginkgo biloba; D005938:Glucocorticoids / Q000633:toxicity; D006023:Glycoproteins / Q000235:genetics; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D009798:Ocular Hypertension / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control*; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage*; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014129:Trabecular Meshwork / Q000187:drug effects* / Q000378:metabolism; D014162:Transfection; D000099179:Myocilin; D000096983:Ginkgo Extract
D003598:Cytoskeletal Proteins; D003907:Dexamethasone; D005136:Eye Proteins; D005938:Glucocorticoids; D006023:Glycoproteins; D010936:Plant Extracts; D012333:RNA, Messenger; D000099179:Myocilin; C063170:Ginkgo biloba extract; D000096983:Ginkgo Extract