Effects of Noise Damage on the Purinergic Signal of Cochlear Spiral Ganglion Cells in Guinea Pigs.

To observe the expression changes of P2 protein in cochlear spiral ganglion cells before and after noise injury, and to explore the relationship between the changes of purinergic receptors in spiral ganglion cells and noise-induced hearing loss, so that the signal transduction of purinergic receptors can be used to treat SNHL The target point provides a theoretical basis. The experimental animals were randomly divided into normal and experimental groups. The experimental group was given 120 dB white noise continuous exposure for 10 days and 3 h a day. The auditory brainstem response was measured before and after the noise exposure. After the noise exposure, the two groups of animals were collected. Do immunofluorescence staining, western blot, fluorescence real-time quantitative PCR to observe the expression of P2 protein. The average hearing threshold of the animals in the experimental group increased to 38.75 ± 6.44 dB SPL after 7 days of noise exposure, and the high-frequency hearing loss was lower and severe; the average hearing threshold increased to 54.38 ± 6.80 dB SPL after 10 days of noise exposure, and the hearing loss at 4 k Hz was relatively high. Light; Frozen sections of cochlear spiral ganglion cells and staining of isolated spiral ganglion cells found that P2X2, P2X3, P2X4, P2X7, P2Y2, and P2Y4 proteins were all expressed in cochlear spiral ganglion cells before noise exposure. Among them, P2X3 expression increased and P2X4, the down-regulation of P2Y2 expression was statistically significant (P < 0.05); Western blot and real-time quantitative PCR detection results showed that the expression of P2X3 was significantly increased after noise exposure than before noise exposure (P < 0.05), and P2X4 and P2Y2 were expressed after noise exposure The amount was significantly lower than before noise exposure (P < 0.05). (Figure. 4). After noise exposure, the expression of P2 protein is upregulated or downregulated. By affecting the Ca2+ cycle, the transmission of sound signals to the auditory center is blocked, which provides a theoretical basis for the signal transduction of purinergic receptors to become a target for the treatment of SNHL.

Acute Noise Causes Down-Regulation of ECM Protein Expression in Guinea Pig Cochlea.

Proteomics technology reveals the marker proteins, potential pathogenesis, and intervention targets after noise-induced hearing loss. To study the differences in cochlea protein expression before and after noise exposure using proteomics to reveal the pathological mechanism of noise-induced hearing loss (NIHL). A guinea pig NIHL model was established to test the ABR thresholds before and after noise exposure. The proteomics technology was used to study the mechanism of differential protein expression in the cochlea by noise stimulation. The average hearing threshold of guinea pigs on the first day after noise exposure was 57.00 ± 6.78 dB Sound pressure level (SPL); the average hearing threshold on the seventh day after noise exposure was 45.83 ± 6.07 dB SPL. The proteomics technology identified 3122 different inner ear proteins, of which six proteins related to the hearing were down-regulation: Tenascin C, Collagen Type XI alpha two chains, Collagen Type II alpha one chain, Thrombospondin 2, Collagen Type XI alpha one chain and Ribosomal protein L38, and are enriched in protein absorption, focal adhesion, and extracellular matrix receptor pathways. Impulse noise can affect the expression of differential proteins through focal adhesion pathways. This data can provide an experimental basis for the research on the prevention and treatment of NIHL.