Ototoxicidade da cisplatina e otoproteção pelo extrato de ginkgo biloba às células ciliadas externas: estudo anatômico e eletrofisiológico

Effect of melatonin on otoprotection in rodents: a systematic review with meta-analysis

OBJECTIVES

To determinate the otoprotective efficacy of melatonin.in experimental models of rodents through a systematic review of the literature.

METHODS

Altogether, 154 articles were found in four databases. The PICOS strategy (Population, Intervention, Comparison, and Outcome) was used to define the eligibility criteria. Studies that met the inclusion criteria for the second step were included in a qualitative synthesis. Each study type was analyzed with the CAMARADES quality of assessment's checklist and the SYRCLE RoBS risk of bias.

RESULTS

Seven articles were selected, and four were included in the meta-analysis. It was possible to obtain seven outcomes according to the standard auditory frequencies presented among the studies, considering a minimum of three standard frequencies. The outcomes analyzed were for the frequencies of 1500, 2000, 3000, 4000, 5000, 6000, and 8000 Hz.

CONCLUSION

Melatonin can provide protection against the ototoxic effects of cisplatin and aminoglycosides at 5000 Hz, 6000 Hz, and 8000 Hz, thereby minimizing the reduction in Otoacustic Emissions (OAE) amplitude. The same effect was not observed in the lower frequencies. Despite the limited number of studies that were evaluated, the results appeared consistent in higher frequencies. However, the methodology of the available studies did not meet the necessary methodological rigor that promotes the safe replicability of these studies.

Traversing through half a century research timeline on Ginkgo biloba, in transforming a botanical rarity into an active functional food ingredient

Neurodegenerative diseases and various other chronic ailments have gradually transformed into public-health issues. Neurodegenerative disorders are a range of progressive neural abnormalities characterized by cellular dysfunctions, neuronal structure, and function loss. Among many chronic disorders, oxidative stress, inflammation, mitochondrial dysregulation, and cellular alterations in the human body are considered the most prevalent diagnostic symptoms. They have a profound impact on patients' health and wellbeing. The disease's poor curability, high healthcare costs, and lethality are the principal reasons for approaching and exploring the conventional treatment's phytotherapeutic alternatives. Ginkgo biloba (Maidenhair tree) is a well-known and widely used herbal plant in the Ginkgoaceae family. Its phytochemical constituents, Flavonoids, and terpenes, have been identified as the primary ingredients of Ginkgo biloba leaf extracts. It has been widely used due to its therapeutic properties, including its neuroprotective, anti-dementia, antioxidant, anti-inflammatory, vasoactive, anti-psychotic, anti-neoplastic, and anti-platelet activity. In recent decades, plenty of Ginkgo-derived substances has been researched and elucidated to have significant therapeutic effects in numerous disease models. This review aims to provide a thorough understanding of the botanical basis for Ginkgo biloba, its usage as herbal medicine, and its pivotal role in functional foods. Additionally, the clinical significance of Ginkgo biloba, as observed in various research works and clinical investigations, is also emphasized, facilitating a better understanding of their molecular basis and application in many chronic diseases.

Prevention of gentamicin ototoxicity with N-acetylcysteine and vitamin A

OBJECTIVE

To investigate the use of systemic N-acetylcysteine and vitamin A in the prevention of gentamicin ototoxicity in rats.

METHODS

Forty-two Wistar rats were divided into four groups according to treatment: intratympanic saline, intratympanic gentamicin, intraperitoneal vitamin A after intratympanic gentamicin, and intraperitoneal N-acetylcysteine after intratympanic gentamicin. Signal-to-noise ratio and distortion product otoacoustic emissions were evaluated in all groups.

RESULTS

N-acetylcysteine had a significant protective effect at 1.5, 2, 3, 4, 6 and 8 kHz, whilst vitamin A had a significant protective effect at 2, 3, 4 and 6 kHz, as determined by the distortion product otoacoustic emission measurements. According to the signal-to-noise measurements, N-acetylcysteine had a significant protective effect at 1.5, 2, 3, 4, 6 and 8 kHz, whilst vitamin A had a significant protective effect at 3, 6 and 8 kHz.

CONCLUSION

Gentamicin-induced hearing loss in rats may be prevented by the concomitant use of vitamin A and N-acetylcysteine. Specifically, N-acetylcysteine appeared to have a more protective effect than vitamin A for a greater range of noise frequencies.

Mechanisms of cisplatin ototoxicity: theoretical review

Introduction:

Cisplatin is an effective chemotherapeutic agent commonly used in the treatment of malignant tumours, but ototoxicity is a significant side effect.

Objectives:

To discuss the mechanisms of cisplatin ototoxicity and subsequent cell death, and to present the results of experimental studies.

Material and methods:

We conducted a systematic search for data published in national and international journals and books, using the Medline, SciELO, Bireme, LILACS and PubMed databases.

Results:

The nicotinamide adenine dinucleotide phosphate oxidase 3 isoform (also termed NOX3) seems to be the main source of reactive oxygen species in the cochlea. These reactive oxygen species react with other molecules and trigger processes such as lipid peroxidation of the plasma membrane and increases in expression of the transient vanilloid receptor potential 1 ion channel.

Conclusion:

Cisplatin ototoxicity proceeds via the formation of reactive oxygen species in cochlear tissue, with apoptotic cell death as a consequence.

Distortion-product otoacoustic emissions and auditory brainstem responses sensitivity assessment in cisplatin-induced ototoxicity in rats

Cisplatin (cis-diamminedicloroplatinum) is an antineoplastic drug used in the treatment of a variety of cancers, especially head-and-neck cancer. Its ototoxicity, however, has been noted as a common side-effect which limits its use and causes significant morbidity.

Aim

to assess distortion-product otoacoustic emissions (DPOAE) and brainstem evoked response audiometry (BERA) sensitivity to detect secondary ototoxicity caused by different doses and means of administration of cisplatin in rats.

Study Design

Experimental.

Materials and Methods

Male Wistar rats were intraperitoneally (i.p.) injected with 24 mg/kg cisplatin, divided into three equal doses (8mg/kg) or a single i.p. injection of 16 mg/kg. The animals were evaluated by distortion product otoacoustic emission (DPOAE) or brainstem evoked response audiometry (BERA) on the 3rd and 4th days after the cisplatin injection.

Results

Treatment with cisplatin 24 mg/kg resulted in significant DPOAE decrease and it raised the BERA electrophysiological threshold. The 16mg/kg dose could not significantly reduce the DPOAE amplitude, but it raised the animals' hearing thresholds – detected by the BERA.

Conclusion

In rats, BERA was more sensitivity than DPOAE at detecting cisplatin-induced ototoxicity in rats considering different doses and means of administration.

Estudo experimental anatômico-funcional da cocleotoxicidade da gentamicina com doses habituais para recém-nascidos

TEMA: a gentamicina é um antibiótico que atua nas infecções causadas por bacilos Gram-negativos. Seu efeito colateral mais importante é a ototoxicidade. As ototoxicoses são afecções iatrogênicas provocadas por fármacos que alteram a orelha interna, podendo afetar o sistema coclear e/ou vestibular, alterando duas funções importantes: a audição e o equilíbrio. Os principais grupos pediátricos que recebem antibióticos aminoglicosídeos são recém-nascidos com infecções graves na UTI neonatal. OBJETIVOS: verificar a ocorrência de lesão às células ciliadas externas (CCE) pela gentamicina com os esquemas de dose única de 4mg/Kg/dia e de 2,5mg/Kg/dia a cada 12 horas, por meio de um estudo anatômico por microscopia eletrônica de varredura (MEV) e estudo funcional através das emissões otoacústicas por produto de distorção (OEAPD). Forma de estudo experimental. MÉTODO: foram avaliadas 26 cobaias albinas através das EOAPD pré e pós-tratamento com gentamicina. Para a avaliação anatômica por MEV, as cobaias foram sacrificadas em tempo programado após a administração das drogas via intramuscular. RESULTADOS: a avaliação do estado funcional das CCE mostrou preservação das OEAPD em todas as cobaias. Os resultados da MEV, depois de fotografados foram analisados através da contagem do número de CCE da espira basal da cóclea em determinado campo fotográfico. CONCLUSÃO: não foram observadas lesões ou alterações no funcionamento das células ciliadas externas mediante a dosagem aplicada em cobaias albinas, de 4mg/Kg/dia (dose única) e 2,5mg/Kg/dia a cada 12 horas, utilizadas por 10 e 14 dias.

Análise de prontuários de pacientes oncológicos quanto ao monitoramento auditivo

OBJETIVO: realizar uma análise retrospectiva dos prontuários de pacientes oncológicos quanto ao monitoramento auditivo. MÉTODOS: foram utilizados os prontuários dos pacientes em atendimento durante os meses de setembro a novembro de 2006. A amostra constituiu-se de 25 prontuários de indivíduos com idade compreendida entre um e 53 anos. Foram analisados os dados quanto aos seguintes aspectos: idade, sexo, classificação do câncer, tempo de apresentação da doença, medicamentos utilizados, tempo de tratamento quimioterápico, doenças associadas, realização de avaliação otorrinolaringológica e audiológica. RESULTADOS: verificou-se a falta de acompanhamento audiológico e otorrinolaringológico. A Vincristina foi o medicamento ototóxico mais utilizado. O tipo de câncer de maior ocorrência no setor foi a Leucemia Linfocítica aguda. O tempo que os indivíduos apresentavam o câncer foi de aproximadamente 16 meses e o tempo de tratamento quimioterápico desses pacientes foi em torno de 11 meses. Observou-se, também, a presença de doenças associadas ao câncer nos indivíduos pesquisados. CONCLUSÃO: constatou-se a necessidade de se instalar programas de monitoramento auditivo nos setores que realizam quimioterapia em pacientes oncológicos, uma vez que este tratamento utiliza medicamentos ototóxicos em diversas patologias.

The use of Maytenus ilicifolia to prevent cisplatin-induced ototoxicity

Maytenus ilicifolia is a native plant from South America, with several medicinal properties including antioxidant effects.

Aim

using an original cisplatin induced ototoxicity model, we evaluated a possible otoprotection caused by Maytenus ilicifolia extract.

Materials and methods

clinical and experimental study design with female albino guinea pigs divided in groups as follows: 9 animals receiving cisplatin only (three doses of 7.5mg/kg/day), 4 animals receiving the plant extract only, 10 animals receiving the cisplatin protocol and 1g/kg/day of extract for 8 days, 5 animals with cisplatin and 3g/kg/day of extract for 8 days, and 5 animals receiving extract for 3 weeks and cisplatin in the last week. The tests were distortion product otoacoustic emissions, brainstem auditory response, before and after medication and scanning electron microscopy.

Results

the animals receiving cisplatin plus plant extract, had alterations in all the tests, showing lesions on the basal cochlear region under electron microscopy.

Conclusions

Despite of the plant extract’s antioxidant effect, it was not sufficient to protect the cochlea against cisplatin ototoxicity.