Morphological analysis of the vestibular system of guinea pigs poisoned by organophosphate

• Published in: Brazilian journal of otorhinolaryngology 2016-01, Vol.82 (1), p.11-16
• Main Authors: Cogo, Lícia Assunção, Alves Valentins dos Santos Filha, Valdete, de Andrade Batista Murashima, Adriana, Hyppolito, Miguel Angelo, Ferreira da Silveira, Aron
• Format: Article
• Language: English
• Subjects: Animals; Cochlea - drug effects; Cochlea - pathology; Disease Models, Animal; Equilíbrio postural; Guinea Pigs; Insecticides - toxicity; Insecticides organophosphate; Inseticidas organofosforados; Male; Organothiophosphorus Compounds - toxicity; Original; OTORHINOLARYNGOLOGY; Pesticides; Postural balance; Praguicidas; Toxicidade; Toxicity; Vestibule labyrinth; Vestibule, Labyrinth - drug effects; Vestibule, Labyrinth - pathology; Vestíbulo do labirinto
• ISSN: 1808-8694; 1808-8686; 1808-8686
• DOI: 10.1016/j.bjorl.2015.10.001

The vestibular system is responsible for body balance. There are substances that damage it, causing dizziness; these are termed vestibulotoxic substances. Agrochemicals have been investigated for ototoxicity because of studies that identified dizziness as a recurrent symptom among rural workers’ complaints. To histopathologically evaluate the vestibular system in guinea pigs exposed to an organophosphate, and to identify the drug's effects on this system. Experimental clinical study. Eighteen guinea pigs were used; six of them poisoned with the organophosphate chlorpyrifos at doses of 0.5mg/kg/day and seven of them at 1mg/kg/day; and a control group of five guinea pigs was exposed to distilled water, all for 10 consecutive days. Later, ciliary tufts of saccule and utricle maculae were counted by scanning electron microscopy. Comparing the groups, a one-way ANOVA test for the variable “saccule” (p=0.0569) and a Kruskal–Wallis test for the variable “utricle” (p=0.8958) were performed, revealing no difference among groups in both variables. The histopathologic analysis of the vestibular system of guinea pigs exposed to an organophosphate showed no difference in the amount of ciliary tufts of saccule and utricle maculae at the doses tested, although the result for the variable “saccule” was considered borderline, showing a trend for significance. O sistema vestibular é responsável pelo equilíbrio corporal. Existem substâncias que o danificam, causando tontura; são chamadas vestibulotóxicas. Agrotóxicos tornaram-se objeto de investigação da ototoxicidade a partir de pesquisas que apontaram tontura como sintoma recorrente entre as queixas de trabalhadores rurais. Constitui-se em avaliar a histopatologia do sistema vestibular de cobaias expostas a organofosforados, identificando os efeitos nesse sistema. É um estudo clínico experimental, que utilizou 18 cobaias, sendo seis intoxicadas com organofosforadoclorpirifós na dose de 0,5mg/kg/dia; sete na dose de 1mg/kg/dia, e grupo controle com cinco cobaias expostas a água destilada, durante 10 dias consecutivos. Posteriormente realizou-se a contagem dos tufos ciliares nas máculas dos sáculos e utrículos através microscopia eletrônica de varredura. Na comparação intergrupos, para a variável sáculo realizou-se o teste ANOVA one-way (p=0,0569); para a variável utrículo, utilizou-se o teste Kruskal-Wallis (p=0,8958), revelando não haver diferença entre os grupos em ambas as variáveis. Análise histopatológica do sistema ve