Modulating Sensory Neuronal Signaling in a Mouse Model Using Near Infrared Light

Take a mouse and shave the dorsal head and neck regions.

Place the mouse on the palm and gently hold its tail.

Position a near-infrared or NIr-emitting device above the shaved region and switch it on.

The NIr light penetrates the scalp and skull, reaching the vestibular sensory epithelium in the inner ear.

This tissue contains sensory hair cells that convert mechanical stimuli into electrical signals.

These signals activate vestibular neurons, which relay this information to the brain.

Inside the hair cells, mitochondria absorb NIr light, enhancing cellular energy production.

This also generates reactive oxygen species, or ROS, as metabolic byproducts.

Excess ROS disrupts the signal transmission from hair cells to the brain.

In response, the cells increase the production of antioxidant enzymes.

These enzymes neutralize ROS and restore signal transmission to the brain during stimuli.

This highlights NIr therapy as a potential neuroprotective strategy to support neuronal function.

Two to three days before starting the experiment, shave the fur on the head and neck regions of each mouse as closely as possible to prevent regrowth of the animal's hair before completion of the treatment regime. To maintain the pathogen free status of the animals, clean the instruments with 70%ethanol between each shaving.

Then on the day of the treatment for each animal intern, pick up the mouse at the proximal end of the tail and allow it to relax in the palm of one hand to minimize stress for the near infrared treated animals. For each animal, hold a 670 nanometer LED device, one to two centimeters away from the shaved area, and switch on the device for 90 seconds. For the sham group, repeat the treatment procedure in the same way, but with the device switched off for the near infrared blocked group, treat the animals in the same way as the near infrared treated group, but with the device covered with aluminum foil.