Melatonin Type 2 Receptor Activation Regulates Blue Light Exposure-Induced Mouse Corneal Epithelial Damage by...

Area of Science:

• Ophthalmology
• Neuroscience
• Cell Biology

Background:

• Melatonin receptors (MT1/2) are G protein-coupled receptors regulating circadian rhythms.
• MT1/2 receptors are implicated in mitochondrial homeostasis, antioxidant, and anti-inflammatory responses in various tissues.
• The role of MT1/2 receptors in corneal health and response to environmental stressors like blue light is not well understood.

Purpose of the Study:

• To investigate the effects of blue light (BL) exposure on melatonin and MT1/2 receptor expression in the mouse cornea.
• To evaluate the functional role of MT1/2 receptors in blue light-induced corneal epithelial damage.

Main Methods:

• 8-week-old C57BL/6 mice were exposed to blue light (25 and 100 J/cm² twice daily for 14 days).
• Expression levels of 4-hydroxynonenal (4-HNE), MT2, p62, BAX, and cleaved caspase 3 were analyzed.
• Mice were treated with an MT2 antagonist to assess its protective effects against blue light damage.
• Malondialdehyde (MDA) levels and corneal damage were evaluated.

Main Results:

• Blue light exposure significantly increased 4-HNE and MT2 expression in the cornea.
• MT2 antagonist treatment in BL-exposed mice led to increased p62 and decreased BAX and cleaved caspase 3 expression.
• MT2 antagonist treatment ameliorated MDA levels and reduced corneal damage compared to BL-exposed mice without antagonist.

Conclusions:

• Blue light exposure induces MT2 receptor expression in the mouse cornea.
• MT2 receptor activation modulates impaired autophagy and apoptosis by upregulating BAX, thus promoting corneal epithelial damage.
• Targeting MT2 receptors may offer a therapeutic strategy for blue light-induced ocular surface damage.