The Putative Mechanisms of Iron-induced Retinal Toxicity

• Main Authors: Yen-Hao Chen, 陳彥豪
• Other Authors: Pen-Ho Yeh
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/63438651387537505660

碩士 === 國立陽明大學 === 藥理學研究所 === 93 === Siderosis bulbi, caused by retained iron-containing intraocular foreign body (IOFB), are vision-threatening diseases. The victims are mainly young males and involved in common activities when injured. Despite a successful surgical removal of the iron IOFB, the iron-damaged retinal functions appear to be irreversible. An investigation into the underlying mechanisms of iron-induced retinal toxicity is crucial. Ferrous sulfate (experimental, 0.8mM, 8mM, and 24mM) or physiological saline (control) was intravitreously injected into one eye of a Wistar rat. Electroretinogram (ERG) was recorded, and the reactive oxygen species (ROS) and glutamate assay performed before and after physiological saline/ferrous sulfate injection. The experimental siderosis was associated with a drastic reduction in the ERG b-wave amplitudes, which occurred 2 hours after experimental siderosis. The injected ferrous sulfate solution, maximally, stimulated the formation of hydroxyl radical and glutamate 20 minutes after ferrous sulfate injection. This implies that the experimental siderosis stimulates an oxidative stress and a subsequent excitotoxicity. These results were consistent with impaired retinal function, as shown by the 12-hour ERG result. This might explain why a retained iron-containing IOFB would clinically cause visual impairment (e.g. ERG, visual field, etc.) despite an uncomplicated surgical removal.