Retinal development impairment and degenerative alterations in adult rats subjected to post-natal malnutrition.

Background: The early stages of central nervous system (CNS) development are extremely important. Key events such as neurogenesis, gliogenesis, synaptogenesis, and ontogenesis occur. Malnutrition promotes alterations in CNS development, including the retinal development. During retinal development, malnutrition can induce a delay in some important events, such as neurotransmitter expression and neurogenesis.

Methodology/principal Findings: Postpartum Wistar rats were fed either a commercial diet or a multideficient diet. Pups were breastfed by these rats, and from PND21 were kept with the same diet until PND45. We investigated the effects of malnutrition on adult retinal tissue with regard to (1) endogenous gamma-amino butyric acid (GABA) release induced by excitatory amino acids (EAAs) and (2) the expression of cellular markers related to degenerative events, such as reactive gliosis, microglial activation, cell proliferation and cell death. Endogenous GABA release induced by EAAs was higher in the retina of malnourished rats. The Müller cell population was reduced and displayed alterations in their phenotype profile compatible with reactive gliosis. The expression of glutamine synthetase and markers of cellular proliferation were higher in the retina of malnourished rats. Additionally, retinal dysplasia-like structures were present, indicating disturbance in the cell cycle machinery.

Conclusion/significance: The current study provides evidence that the adult retina shows degenerative processes induced by long-term malnutrition during the postnatal development. These findings have high clinical significance with regard to the identification of possible targets for interventions in malnourished patients.