Glutamate-induced retinal lipid and protein damage: the protective effects of catechin.
Glutamate toxicity has been implicated in various retinal diseases. Green tea leaf extract catechin has protective effects against cellular toxicity. This study investigated the effects of catechin on the glutamate-treated retina. Porcine retinal homogenates were incubated with glutamate (20 nmol) at 37 degrees C for 60 min. Catechin was co-incubated with the glutamate-treated retina in the same condition. The malondialdehyde (MDA) levels were determined as an index of lipid peroxidation (LPO). Differential protein expressions were derived from two-dimensional gel electrophoresis. Mass spectrometry was conducted to identify the proteins. Glutamate increased the retinal MDA (p<0.0001) and catechin reversed the effect (p<0.0001). There were significant changes in seven proteins after the glutamate treatment (p<0.05), namely, heterogeneous ribonucleoprotein, thioredoxin peroxidase, 5-hydroxytryptamine receptor, pyruvate dehydrogenase, ARHA protein, peroxiredoxin 6 and proteasome. Catechin significantly reversed the changes in thioredoxin peroxidase, 5-hydroxytryptamine receptor, peroxiredoxin 6 and pyruvate dehydrogenase (p<0.05). Our study shows that (a) retinal glutamate toxicity is mediated by LPO and protein modification, and (b) catechin ameliorates the toxicity.
Siu
Andrew W
AW
School of Optometry, The Hong Kong Polytechnic University, Yuk Choi Road, Hunghom, Hong Kong, China. siuanz@gmail.com
Lau
Mick K
MK
Cheng
John S
JS
Chow
Catherine K
CK
Tam
Wai C
WC
Li
K K
KK
Lee
Daniel K L
DK
To
Tony S S
TS
To
Chi H
CH
Do
Chi W
CW
D000818:Animals; D002392:Catechin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D018698:Glutamic Acid / Q000633:toxicity*; D066298:In Vitro Techniques; D015227:Lipid Peroxidation / Q000187:drug effects*; D008315:Malondialdehyde / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods; D011506:Proteins / Q000378:metabolism; D012160:Retina / Q000187:drug effects*; D013552:Swine
D011506:Proteins; D018698:Glutamic Acid; D008315:Malondialdehyde; D002392:Catechin