Inducing Hearing Loss in Mice Through Prolonged High-Volume Sound Exposure

Protokół

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.  

1. Induction of noise-induced hearing loss (NIHL) in mice

1. Prepare the cage for the experimental mice
   1. To do so, use a rat trap cage with dimensions of 14 cm × 17 cm × 24 cm. Cut four pieces of corrugated plastic boards into appropriate sizes, making them fit into the cage (13 cm × 23 cm and 13 cm × 16 cm).
   2. To prevent the mice from getting their feet cut by the mesh grid, place two of the pieces at the bottom and on the back side, respectively. Place the other two pieces perpendicularly interlocked with each other, to divide the space within the cage into quarters.
2. Carry out this study in a soundproof box. Place a speaker 8.5 cm in front of the cage, and place both the speaker and the cage in a soundproof box.
3. Open the CLIO application software.
4. Move the cursor to the speaker icon, then click on TwoSin. Enter and change the value of Freq 1 to 1000 Hz, and Freq 2 to 6000 Hz, and click on OK to start playing the sound.
5. Under the Leq tab, change decibel Volt (dBV) to decibels Sound Pressure Level (dBSPL). After setting the time on the software interface, click the green triangle button to play the sound.
6. Place a microphone in front of the speaker at a distance of 8.5 cm to calibrate the noise level (Figure 1). Adjust the noise level to 125 dB SPL-A and continuously monitor for no less than 3 min to ensure that the noise level is sufficiently stable. Use a generator, an analyzer, and an amplifier to create and control the noise. (Figure 2)
   NOTE: Do this step in a soundproof box to avoid damage to the operator's hearing.
7. Place four male C57BL/6J mice into the cage (one for each quarter) for noise exposure. Randomly assign the mice in each quarter during the noise exposure. Place a microphone on the top of the cage to monitor the noise level during the noise exposure (Figure 3).
   NOTE: Do this step in a soundproof box to avoid damage to the operator's hearing.
8. Expose the mice to the noise at frequencies of 1 kHz and 6 kHz continuously for 6 h per day, for 5 consecutive days.

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Wyniki

Figure 1: Voltage calculation from calibration. For each specific frequency, the value of the selected voltage (horizontal axis) will be input into the calibration curve to obtain the corres...

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