Abstract
Purpose: :
Saffron, an extract from Crocus sativus, has been largely used in traditional medicine for its antiapoptotic and anticarcinogenic properties. Rats prefeeding with saffron provides protection against photoreceptor death induced by exposure to continuous bright light. In this work we used safranal, a component of saffron stigmas, to investigate its effects against retinal degeneration in the P23H rat model of autosomal dominant retinitis pigmentosa.
Methods: :
Homozygous P23H line-3 rats were used in this study. Animals (20 days to 4 months old) were injected with safranal (400 mg/kg, i.p.) twice a week. Retinal function was assessed by electroretinography. Cryostat vertical sections of retinas were subjected to single and double labeling with antibodies to specific neuronal markers and the nuclear-staining dye TO-PRO. Images were obtained by means of immunofluorescence confocal microscopy. NAPDH diaphorase histochemistry on whole-mount retinas was performed to visualize the retinal vascular network.
Results: :
Recoverin and transducin immunoreactivity showed a preservation of photoreceptor inner and outer segments in the retina of safranal-treated rats as compared to vehicle-treated subjects. The number of rows of photoreceptors in the ONL was 4-6 in the central retina, compared with 1-2 rows in non-treated animals. In the peripheral retina of safranal-injected animals the number of conserved photoreceptor rows was double than in controls. Electroretinographic analysis showed higher a- and b-wave amplitudes under both photopic and scotopic conditions in safranal-treated versus non-treated animals. In 4 month-old P23H rats the retinal capillary network was significantly reduced, and capillary loops appeared degenerated. In contrast, the capillary network in safranal-treated animals was well preserved, suggesting a positive effect of this compound on the prevention of retinal degeneration.
Conclusions: :
Treatment with safranal slows photoreceptor cell degeneration, and ameliorates the loss of retinal function and vascular network disruption taking place in P23H rats. This work indicates that safranal could be potentially useful to retard retinal degeneration in retinitis pigmentosa.
Keywords: retina: distal (photoreceptors, horizontal cells, bipolar cells) • neuroprotection • retinitis