Repeated formaldehyde inhalation impaired olfactory function and changed SNAP25 proteins in olfactory bulb

Area of Science:

• Neuroscience
• Toxicology

Background:

• Occupational formaldehyde inhalation can cause sensory irritation, neurotoxicity, and cognitive deficits.
• The specific impact of formaldehyde on olfactory function remains largely unknown.

Purpose of the Study:

• To investigate the mechanism by which repeated formaldehyde inhalation affects olfactory function.
• To determine the impact of formaldehyde exposure on olfactory sensory neurons and associated proteins.

Main Methods:

• Rats underwent 14 days of formaldehyde inhalation exposure (13.5±1.5 ppm).
• Olfactory function was assessed using buried food pellet tests; locomotion was monitored.
• Western blotting and RT-PCR analyzed protein and mRNA levels of SNAP25, OMP, and Tuj-1 in the olfactory bulb.

Main Results:

• Formaldehyde exposure significantly impaired olfactory function but did not affect locomotion.
• Synaptosomal-associated protein 25 (SNAP25) protein levels decreased in the olfactory bulb (OB) and its synaptosomes, while mRNA levels remained unchanged.
• Levels of mature and immature olfactory sensory neuron markers (OMP, Tuj-1) were unaffected.

Conclusions:

• Repeated formaldehyde inhalation exposure impairs olfactory function.
• The mechanism involves the disruption of SNAP25 protein levels within the olfactory bulb.