[Protective effect of cicletanine in hypertensive retinopathy. Evaluation of retinal function in the isolated retina]

In order to demonstrate functional impairments related to hypertensive retinopathy, we experimented on the isolated retina of spontaneously hypertensive rats (SHR-SP strain A3N Iffa Credo). We also used this experimental model to assess the protective effect of treatment with cicletanine, a new synthetic furopyridine compound. Treatment consisted of daily oral administration of either 50 or 100 mg/kg of cicletanine for 5 weeks. Retinal function was evaluated by recording the electroretinogram (ERG) obtained in response to light stimulation (300 lux, 1 ms) of the isolated retina maintained in survival by perfusion. The results indicate: (i) that ERG amplitude remains systematically lower in hypertensive rats than in normotensive rats and that in consequence retina survival is shortened; (ii) that in cicletanine-treated hypertensive rats ERG amplitude is significantly higher than in untreated hypertensive rats, the drug augmenting the duration of retina survival. Although cicletanine significantly improved the ERG amplitude obtained in hypertensive rats, this amplitude was still lower than in normotensive rats. These results are consistent with those of previous histological studies performed on the same of hypertensive rats, which demonstrated that impairments of retinal capillaries, photoreceptors and ganglion cells may have deleterious functional consequences for the visual process. Cicletanine is able to reduce these histological impairments, and the present study demonstrate that the drug can also significantly improve the ERG amplitude.