Abstract
Purpose :
Retinal structure and cell type composition are generally well conserved across all vertebrate species. Differences in the precise complement of retinal cell types among closely related species can reflect functional adaptations to daily activity and/or life history. Among the order Rodentia, retinal anatomy and physiology are predominantly studied in mice and rats, but there is renewed interest in incorporating additional rodent models that exhibit interesting behaviors and visual adaptations. The African spiny mouse has been studied for its unique behavioral qualities, precocial development, and recently, for its regenerative abilities. However, the spiny mouse retinal anatomy has not been rigorously studied. Here, we present a comparative analysis of retinal cell type morphology and number in Acomys cahirinus and Mus musculus adult retinas.
Methods :
All animal procedures were performed in accordance with guidelines established by IACUC and the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. Retinal tissue sections were obtained from adult eyes and subjected to histological staining or immunohistochemistry with antibodies for various retinal cell types. Sections were imaged by light, fluorescence, and confocal microscopy. Cell number and morphology were assessed. Comparison of cell number between species was assessed using a Student’s t test. Data are presented as mean ± SD.
Results :
Overall, the general features of retinal anatomy between Acomys and Mus are similar. With roughly triple the eye size, the retinal layers of the Acomys are of similar thickness and, for the majority of retinal cell types, the morphology appears comparable in the two species. However, Acomys bipolar cells show an increased number and altered laminar positioning compared to Mus. Intriguingly, we also observe a differential patterning and distribution of Acomys photoreceptors, particularly the cones.
Conclusions :
Taken together, the differences in photoreceptors and bipolar cells could suggest differences in visual acuity between the two species, possibly due to visual adaptations for foraging food in their unique desert environment. These results set the stage to investigate retinal cell type diversity and visual function in this interesting mammalian model.
This is a 2021 ARVO Annual Meeting abstract.