N-acetyl-serotonin reduces copper (I) ion-induced lipid peroxidation in bovine retinal homogenates.
OBJECTIVE
Chalcosis is an ocular condition caused by penetration injury of copper or its alloy, which leads to extensive ocular inflammation. N-acetyl-serotonin has recently been identified as a potent antioxidant against free radical stress. In this study, we determined the efficacy of N-acetyl-serotonin against the copper (I)-induced retinal lipid peroxidation.


METHODS
Copper (I)-treated (100 microM) bovine retinal homogenates were incubated with 6 different concentrations (i.e. 0.00, 0.25, 0.50, 1.00, 2.00 and 4.00 mM) of N-acetyl-serotonin or vitamin E. The malondialdehyde level was measured as an index of lipid peroxidation.


RESULTS
Copper (I) ions induced a significant dose-dependent increase in malondialdehyde (p=0.007). Co-incubation with N-acetyl-serotonin or vitamin E significantly suppressed the copper (I)-induced malondialdehyde production (p<0.0001). The concentration to inhibit 50% of damage for N-acetyl-serotonin and vitamin E were found to be 1.54 mM and 0.45 mM, respectively.


CONCLUSIONS
Although N-acetyl-serotonin is only 29% as effective as vitamin E in suppressing the copper (I)-induced lipid peroxidation, the present study supports a pharmacological potential of N-acetyl-serotonin combating free radical oxidative damages in the ocular tissues.
Siu
A W
AW
Department of Optometry and Radiography, Faculty of Health & Social Sciences, The Hong Kong Polytechnic University, Kowloon, China. orsiua@polyu.edu.hk
Cheung
J P
JP
To
C H
CH
Chan
E K
EK
Chan
J K
JK
Cheung
J C
JC
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002417:Cattle; D003300:Copper / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D015227:Lipid Peroxidation / Q000187:drug effects*; D008054:Lipid Peroxides / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D012160:Retina / Q000187:drug effects* / Q000378:metabolism; D012701:Serotonin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D014810:Vitamin E / Q000494:pharmacology
D000975:Antioxidants; D008054:Lipid Peroxides; D014810:Vitamin E; D012701:Serotonin; D008315:Malondialdehyde; D003300:Copper; C028419:cuprous chloride; C006389:N-acetylserotonin