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Updated: Jun 26, 2026
Methodology for Biomimetic Chemical Neuromodulation of Rat Retinas with the Neurotransmitter Glutamate In Vitro
Published on: December 19, 2017
Early postnatal enriched environment decreases retinal degeneration induced by monosodium glutamate treatment in rats
Krisztina Szabadfi1, Tamás Atlasz, Gábor Horváth
1Department of Experimental Zoology and Neurobiology, Pecs, Hungary.
Insights
Environmental enrichment and larger cages protect against retinal degeneration caused by monosodium glutamate (MSG) in developing rats. Enriched environments offer significant neuroprotection for the visual system.
Area of Science:
- Neuroscience
- Ophthalmology
- Developmental Biology
Background:
- Environmental enrichment impacts nervous system development and brain lesion recovery.
- Housing conditions influence visual system development and function.
- Neonatal exposure to monosodium glutamate (MSG) induces retinal degeneration.
Purpose of the Study:
- To investigate the neuroprotective effects of expanded cage size and enriched environments on MSG-induced retinal degeneration in rats.
- To assess the impact of housing conditions on retinal structure following neonatal MSG treatment.
Main Methods:
- Rats were housed in regular, expanded, or enriched environments from postnatal day 1.
- Neonatal monosodium glutamate (MSG) or saline treatment was administered on specific days.
- Retinal histology was performed at 5 weeks of age to analyze structural integrity.
Main Results:
- MSG treatment caused severe inner retinal degeneration, reducing retinal thickness to less than 25% of normal.
- Expanded cage housing showed a significant protective effect, with retinal thickness ameliorating by nearly 50%.
- Enriched environments yielded the best results, with only a ~25% reduction in retinal thickness and preserved retinal layers.
Conclusions:
- Expanded housing provides partial neuroprotection against MSG-induced retinal damage.
- Complex environmental enrichment offers significant protection against neonatal MSG-induced retinal degeneration.
- Environmental factors play a crucial role in mitigating neurodevelopmental insults to the visual system.
Abstract:
Environmental enrichment is known to influence the development of the nervous system and it provides beneficial effects in various kinds of brain lesions. Enriched housing conditions also influence the development and functioning of the visual system. The aim of the present study was to investigate whether retinal degeneration induced by neonatal monosodium glutamate (MSG) in rats can be ameliorated by expanded cage size or enriched environment. Control rats were kept in a regular cage, another group of pups was kept in an expanded cage and a third group was kept under complex environmental enriched conditions from the first postnatal day. Half of the rats received MSG treatment on postnatal days 1, 5, and 9, while the other half of the groups received only saline treatment. Retinas were removed at 5 weeks of age and processed for histological analysis. Microscopical analysis revealed a substantial inner retinal degeneration in MSG-treated animals: the retinal thickness was less than 25% of the normal retinas, and the inner layers were completely fused. Expanded cage environment had a significant protective effect: the layers of the retina were well visible, and the thickness of the entire retina had a nearly 50% amelioration. Best results were obtained in retinas from rats living in enriched environment: the retina suffered only an approximately 25% reduction in thickness, and all layers were significantly thicker than in MSG-treated retinas. In summary, the present study showed that expanded field provided some degree of neuroprotection, while a complex environmental enrichment led to a manifest protection against retinal degeneration induced by neonatal MSG treatment in rats.
