Effects of enriched endogenous omega-3 fatty acids on age-related hearing loss in mice

Dietary intervention is a practical prevention strategy for age-related hearing loss (AHL). Omega-3 (n-3) polyunsaturated fatty acids (PUFAs) may be effective in prevention of AHL due to their anti-inflammatory and tissue-protective functions. Age-related changes in the hearing function of wild-type and Fat-1 transgenic mice derived from the C57BL/6N strain, which can convert omega-6 PUFAs to n-3 PUFAs and consequently produce enriched endogenous n-3 PUFAs, were investigated to test the efficacy of n-3 PUFAs for AHL prevention. At 2 months, the baseline auditory brainstem response (ABR) thresholds were the same in Fat-1 and wild-type mice at 8–16 kHz but were significantly higher in Fat-1 mice at 4 and 32 kHz. In contrast, the ABR thresholds of Fat-1 mice were significantly lower at 10 months. Moreover, the ABR thresholds of Fat-1 mice at low-middle frequencies were significantly lower at 13 months (12 kHz). Body weights were significantly reduced in Fat-1 mice at 13 months, but not at 2, 10, and 16–17 months. In conclusion, enriched endogenous n-3 PUFAs produced due to the expression of the Fat-1 transgene partially alleviated AHL in male C57BL/6N mice.