Neuroprotective effects of minocycline against in vitro and in vivo retinal ganglion cell damage.
The purpose of this study was to determine whether minocycline, a semi-synthetic tetracycline derivative, reduces (a) the in vitro neuronal damage occurring after serum deprivation in cultured retinal ganglion cells (RGC-5, a rat ganglion cell line transformed using E1A virus) and/or (b) the in vivo retinal damage induced by N-methyl-D-aspartate (NMDA) intravitreal injection in mice. In addition, we examined minocycline's putative mechanisms of action against oxidative stress and endoplasmic reticulum (ER) stress. In vitro, retinal damage was induced by 24-h serum deprivation, and cell viability was measured by Hoechst 33342 staining or resazurin reduction assay. In cultures of RGC-5 cells maintained in serum-free medium for up to 24 h, the number of cells undergoing cell death was reduced by minocycline (0.2-20 microM). Serum deprivation resulted in increased oxidative stress, as revealed by an increase in the fluorescence intensity for 5-(and-6)-chloromethyl-2', 7'-dichlorodihydrofluorescein diacetate (CM-H2DCFDA), a reactive oxygen species (ROS) indicator. Minocycline at 2 and 20 microM inhibited this ROS production. However, even at 20 microM minocycline did not inhibit the retinal damage induced by tunicamycin (an ER stress inducer). Furthermore, in mice in vivo minocycline at 90 mg/kg intraperitoneally administered 60 min before an NMDA intravitreal injection reduced the NMDA-induced retinal damage. These findings indicate that minocycline has neuroprotective effects against in vitro and in vivo retinal damage, and that an inhibitory effect on ROS production may contribute to the underlying mechanisms.
Shimazawa
Masamitsu
M
Department of Biofunctional Molecules, Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi, Gifu 502-8585, Japan.
Yamashima
Tetsumori
T
Agarwal
Neeraj
N
Hara
Hideaki
H
D000818:Animals; D001562:Benzimidazoles; D001583:Benzoxazoles; D002452:Cell Count / Q000379:methods; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D016895:Culture Media, Serum-Free / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004721:Endoplasmic Reticulum / Q000187:drug effects; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity; D005456:Fluorescent Dyes; D008297:Male; D051379:Mice; D008911:Minocycline / Q000494:pharmacology* / Q000627:therapeutic use; D016202:N-Methylaspartate / Q000633:toxicity; D018696:Neuroprotective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D011419:Propidium; D011806:Quinolinium Compounds; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D012160:Retina / Q000187:drug effects / Q000473:pathology; D012164:Retinal Diseases / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D012165:Retinal Ganglion Cells / Q000187:drug effects*; D014415:Tunicamycin / Q000633:toxicity
D001562:Benzimidazoles; D001583:Benzoxazoles; D016895:Culture Media, Serum-Free; D018690:Excitatory Amino Acid Agonists; D005456:Fluorescent Dyes; D018696:Neuroprotective Agents; D011806:Quinolinium Compounds; D017382:Reactive Oxygen Species; D014415:Tunicamycin; C089813:YO-PRO 1; D011419:Propidium; D016202:N-Methylaspartate; D008911:Minocycline; C017807:bisbenzimide ethoxide trihydrochloride