Ahmed Dellaa1,2, Anna Polosa3, Sihem Mbarek1, Imane Hammoum1, Riadh Messaoud4, Soumaya Amara4, Rached Azaiz5, Ridha Charfeddine5, Mohamed Dogui6, Moncef Khairallah4, Pierre Lachapelle3, Rafika Ben Chaouacha-Chekir1. 1. a UR Ecophysiologie et Procédés Agroalimentaires , Institut Supérieur de Biotechnologie, Université de la Manouba , Ariana , Tunisie. 2. b Faculté des Sciences de Bizerte , Université de Carthage , Zarzouna , Tunisie. 3. c Département d'Ophtalmologie , Institut de Recherche du Centre Universitaire de santé McGill , Montréal , Canada. 4. d Service d'Ophtalmologie, CHU Fattouma Bourguiba , Monastir , Tunisie. 5. e Industrie Pharmaceutique UNIMED, Zone Industrielle, Kalaa Kebira , Sousse , Tunisie. 6. f Service d'Explorations Fonctionnelles du Système Nerveux, Hôpital Universitaire Sahloul , Sousse , Tunisie.
Abstract
PURPOSE: To compare the retinal function of a diurnal murid rodent, Psammomys obesus, with that of Wistar albino rat and human subjects. MATERIALS AND METHODS: Adult Psammomys obesus were captured and transferred to the animal facilities where they were maintained at 25°C with standard light/dark cycles and natural halophilic plants, rich in water and mineral salts. Standard full-field photopic and scotopic electroretinograms were obtained. RESULTS: The right eye of all animals displayed well detectable and reproducible scotopic and photopic electroretinogram (ERG) responses. Results were compared with those obtained from human subjects and Wistar rats. ERG measurement showed that the amplitudes of scotopic responses in Psammomys obesus are quite similar to those of human subjects. The amplitude of the photopic a-wave was comparable to that of humans and six times higher than that of the albino rat. The amplitudes of photopic b-wave, photopic oscillatory potentials (OPs), and 30 Hz flicker were all markedly larger in Psammomys obesus compared to those obtained from human subjects and Wistar rats. Furthermore, like the human photopic ERG, the photopic ERG of Psammomys obesus also includes prominent post b-wave components (i.e. i- and d-waves) while the ERG of Wistar rats does not. CONCLUSIONS: Our results suggest that the retinal function of Psammomys obesus, especially the cone-mediated function, shares several features with that of human subjects. We believe that Psammomys obesus represents an interesting alternative to study the structure and function of the normal and diseased retina in a human-like rodent model of retinal function.
PURPOSE: To compare the retinal function of a diurnal murid rodent, Psammomys obesus, with that of Wistar albino rat and human subjects. MATERIALS AND METHODS: Adult Psammomys obesus were captured and transferred to the animal facilities where they were maintained at 25°C with standard light/dark cycles and natural halophilic plants, rich in water and mineral salts. Standard full-field photopic and scotopic electroretinograms were obtained. RESULTS: The right eye of all animals displayed well detectable and reproducible scotopic and photopic electroretinogram (ERG) responses. Results were compared with those obtained from human subjects and Wistar rats. ERG measurement showed that the amplitudes of scotopic responses in Psammomys obesus are quite similar to those of human subjects. The amplitude of the photopic a-wave was comparable to that of humans and six times higher than that of the albino rat. The amplitudes of photopic b-wave, photopic oscillatory potentials (OPs), and 30 Hz flicker were all markedly larger in Psammomys obesus compared to those obtained from human subjects and Wistar rats. Furthermore, like the human photopic ERG, the photopic ERG of Psammomys obesus also includes prominent post b-wave components (i.e. i- and d-waves) while the ERG of Wistar rats does not. CONCLUSIONS: Our results suggest that the retinal function of Psammomys obesus, especially the cone-mediated function, shares several features with that of human subjects. We believe that Psammomys obesus represents an interesting alternative to study the structure and function of the normal and diseased retina in a human-like rodent model of retinal function.