Minocycline protects photoreceptors from light and oxidative stress in primary bovine retinal cell culture.
OBJECTIVE
To determine whether minocycline, a compound known to protect the retina against light-induced damage in rodent models, and its structurally related analogues would protect photoreceptor cells in primary bovine retinal cell culture against light and oxidative stress.


METHODS
Minocycline and its analogues were tested in primary retinal cell culture to see whether they would inhibit light or oxidative stress-induced cell death. Primary cell cultures composed of photoreceptors, bipolar cells, and glial cells were prepared from bovine retinas. The extent of cell death induced by light or oxidative stress was assessed by using Sytox Green (Invitrogen-Molecular Probes, Eugene, OR) a nucleic acid dye uptake assay. Differential protection of photoreceptor cells from stress were examined using immunocytochemistry.


RESULTS
Minocycline and methacycline were cytoprotective against light- or oxidative stress-induced damage of bovine primary photoreceptors in culture with an EC(50) < 10 microM. In contrast, structurally related analogues such as demeclocycline, meclocycline, and doxycycline were phototoxic at >3 to >10 microM. Though demeclocycline was found to be phototoxic, it was cytoprotective (EC(50) = 5 microM) against oxidative stress in the absence of exposure to light.


CONCLUSIONS
The protective action of minocycline against light-induced damage in the cell-based assays agrees with earlier reports in animal models and suggests that the in vitro assay using bovine primary retinal cell culture is a suitable model for evaluating compounds for retinal protection. Cellular protection or toxicity produced by structurally related compounds show that minor structural modifications can alter the function of minocycline and lead to potent retinal protective compounds.
Leung
David W
DW
Acucela, Inc., Bothell, Washington 98021, USA. dwleung@acucela.com
Lindlief
Lance A
LA
Laabich
Aicha
A
Vissvesvaran
Ganesh P
GP
Kamat
Mahesh
M
Lieu
Kuo L
KL
Fawzi
Ahmad
A
Kubota
Ryo
R
D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D017209:Apoptosis / Q000528:radiation effects; D020169:Caspases / Q000378:metabolism; D002417:Cattle; D018929:Cell Culture Techniques; D019610:Cytoprotection; D019084:Fluorescent Antibody Technique, Indirect; D005456:Fluorescent Dyes; D008027:Light; D008911:Minocycline / Q000627:therapeutic use*; D009457:Neuroglia / Q000187:drug effects / Q000528:radiation effects; D009930:Organic Chemicals; D018384:Oxidative Stress / Q000187:drug effects*; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects* / Q000528:radiation effects*; D011833:Radiation Injuries, Experimental / Q000473:pathology / Q000517:prevention & control*; D017382:Reactive Oxygen Species / Q000378:metabolism; D051245:Retinal Bipolar Cells / Q000187:drug effects / Q000528:radiation effects; D012164:Retinal Diseases / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D020122:tert-Butylhydroperoxide / Q000633:toxicity
D000900:Anti-Bacterial Agents; D005456:Fluorescent Dyes; D009930:Organic Chemicals; D017382:Reactive Oxygen Species; C402795:SYTOX Green; D020122:tert-Butylhydroperoxide; D020169:Caspases; D008911:Minocycline