Effect of Pycnogenol® on Noise-Induced Hearing Loss in Rats.

Background: This study aims to elucidate the potential protective effects of Pycnogenol® against noise-induced hearing (NIHL) loss in a rat model. Methods: This study employed a randomized controlled design to investigate the potential protective effects of Pycnogenol® against NIHL in a rat model. Twenty-five male Wistar albino rats were randomly assigned to 5 groups (n=5 per group): a control group receiving saline administration, a noise exposure group, a noise+saline receiving group, only Pycnogenol® receiving group, and finally, a Pycnogenol® treatment group receiving daily oral administration of Pycnogenol® at 40 mg/kg/day via gavage for 7 days following noise exposure. All groups were subjected to auditory brainstem response assessments at 4 time points: pre-exposure (baseline), post-exposure day 1, day 7, and day 21. Both noise exposure and the Pycnogenol® treatment groups were exposed to 4 kHz narrowband noise at 120 dB SPL for 4 hours. Following sacrifice, histological and immunohistochemical evaluations were conducted on cochlear tissues. Statistical analyses were performed using SPSS software version 25 to determine significant differences between groups and across time points. Results: Outcome of this research shows that the auditory brainstem response thresholds and cochlear morphology between the experimental and control groups are significantly different from each other, suggesting that Pycnogenol® may have the potential to prevent NIHL loss in rats. Conclusion: Pycnogenol® shows potential in protecting against NIHL. However, further research, particularly at the molecular level, is necessary to better understand its therapeutic mechanisms and its specific impact on auditory metabolic processes.