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[Involvement of PAF (Platelet-Activating Factor) in chloroquine-induced retinopathy]
G Meyniel1, M Doly, M Millerin
1Laboratoire de Biophysique, I.N.S.E.R.M., n. U71, Facultés de Médecine et de Pharmacie, Clermont-Ferrand.
Abstract:
Chloroquine retinopathy is a severe toxic retinal impairment which may result in loss of vision by alterations of the pigmentary epithelium and photoreceptors. Currently, there is no specific treatment for this retinopathy. In order to test the possible involvement of Platelet-Activating Factor (PAF) in chloroquine-induced retinopathy and the use of PAF antagonists for prevention of this condition, we have examined the effect of these substances on the electroretinogram (ERG) of isolated rat retina. When retinas from normal rats were perfused with chloroquine (10(-6) M), a marked and rapid decrease in ERG b-wave amplitude was observed. In contrast, chloroquine had no effect on the ERG of retina isolated from animals pretreated with the PAF antagonist, BN 50730 (30 mg/kg/day i.p., 5 days). The results obtained indicate that (i) chloroquine is a toxic drug for retinal function, (ii) PAF plays a key role in chloroquine retinopathy and (iii) PAF antagonists may constitute valuable agents for the treatment of this retinal impairment.
Insights
Platelet-Activating Factor (PAF) plays a key role in chloroquine retinopathy, a vision-impairing condition. PAF antagonists show promise in preventing this toxic retinal damage.
Area of Science:
- Ophthalmology
- Toxicology
- Pharmacology
Context:
- Chloroquine retinopathy is a severe vision-threatening condition caused by toxic retinal damage.
- No specific treatments currently exist for chloroquine-induced retinopathy.
- Platelet-Activating Factor (PAF) involvement in this condition is under investigation.
Purpose:
- To investigate the role of Platelet-Activating Factor (PAF) in chloroquine-induced retinopathy.
- To evaluate the potential of PAF antagonists in preventing chloroquine retinopathy.
- To assess the effects of chloroquine and PAF antagonists on electroretinogram (ERG) in isolated rat retinas.
Summary:
- Chloroquine (10(-6) M) perfusion significantly reduced ERG b-wave amplitude in normal rat retinas.
- Pretreatment with the PAF antagonist BN 50730 prevented chloroquine-induced ERG alterations.
- These findings highlight PAF's crucial role in chloroquine retinopathy.
Impact:
- Chloroquine is confirmed as toxic to retinal function.
- PAF is identified as a key mediator in chloroquine retinopathy.
- PAF antagonists represent a potential therapeutic strategy for preventing chloroquine retinopathy.