Otoprotective effect of the use of antioxidants on noise exposure in experimental studies with rodents - A systematic review with meta-analysis.

Abstract

OBJECTIVE: To determine the occurrence of otoprotective effect of the use of antioxidants on noise exposure in experimental models with rodents through a systematic review. METHODS: An electronic search was conducted in EMBASE, LILACS, PubMed/Medline, Scopus, Web of Science databases, and in the grey literature of articles published up to June 2022. In the PICO strategy, the studied population consisted of rodent animals exposed to high levels of sound pressure, the intervention consisted of the use of antioxidants, the comparison with the concomitant use of placebo and the results of audiological tests such as Evoked Otoacoustic Emissions and Brainstem Auditory Evoked Potential and the results of histological and immunohistochemical evaluations were collected as outcomes. The analysis of the numerical data was performed according to the Review Manager (Cochrane), using the mean difference as a measure of effect. RESULTS: 35 studies were included in the qualitative synthesis and 27 in the quantitative synthesis. The analysis carried out by CAMARADES indicates that most of the included studies demonstrate methodological quality, and the SYRCLE RoB risk of bias assessment protocol revealed a high risk of bias in all eligible studies. In the analysis of the meta-analysis, the effect generated by the use of antioxidants was notorious in comparison with groups that were exposed to the same noise, without the use of antioxidant. Using the ABR responses at the most commonly used frequencies of 2,000-32,000 Hz as outcomes, it was possible to observe in all analyses an otoprotective effect caused by the use of the antioxidant. CONCLUSION: This systematic review with meta-analysis demonstrated the variable otoprotective effect of the use of antioxidants on exposure to sound pressure levels in experimental studies with rodents, despite the high risk of bias and great heterogeneity of the selected studies.