Short-wavelength artificial light affects visual neural pathway development in mice.

Area of Science:

• Neuroscience
• Ophthalmology
• Developmental Biology

Background:

• Modern life relies heavily on artificial light, which can negatively impact health.
• Short-wavelength artificial light, particularly violet light, is implicated in various health issues, including ocular and mental problems.
• The precise effects of artificial light spectrum on the developing mammalian visual neuronal pathway remain poorly understood.

Purpose of the Study:

• To investigate how different artificial light spectra influence the development of the visual neuronal pathway in mice.
• To assess the impact of short-wavelength light on ocular development, visual function, and retinal neuronal structure.

Main Methods:

• C57BL/6 mice were exposed to full-spectrum white, violet, or green light from eye opening (7:00-19:00).
• Ocular axial dimensions, visual acuity, retinal electrical activity, cone density, retinal ganglion cell density, and axonal structures were assessed.
• Gene expression analysis (KEGG and GO enrichment) was performed to identify affected pathways.

Main Results:

• Short-wavelength light exposure led to shorter ocular axial length, reduced visual acuity, and impaired retinal electrical activity.
• S-cone density decreased, while amacrine cells showed increased activation.
• Axonal terminals in the lateral geniculate nucleus (LGN) became less clustered, and genes related to neural circuitry and neurotransmitter function were differentially expressed.

Conclusions:

• Early-stage exposure to short-wavelength artificial light delays visual pathway development in mice.
• Alterations in axon terminus structure and neurotransmitter function appear to be key consequences.
• Green light showed minimal effects, suggesting wavelength-specific impacts on visual system development.