Evaluation of histopathological alterations caused by different concentrations of the acaricide carvacrol on the thyroid gland and liver of female Mus musculus mice

Abstract

Carvacrol, a monoterpene present in essential oils of aromatic plants, has demonstrated significant acaricidal potential on Rhipicephalus sanguineus sensu lato (s.l.), Amblyomma cajennense, Rhipicephalus microplus and Dermacentor nitens ticks. The biological activities of this compound have been demonstrated in vitro; however, the in vivo effects of carvacrol have not been clarified, including its toxicity for non-target organisms. In this context, the objective of the present study is to evaluate the histopathological alterations in the cells and tissues of the thyroid (endocrine) and liver of mice exposed to carvacrol, simulating what would occur to the host cells and tissues. The Mus musculus mice to be used in this experiment will be provided by CPPA (Research and Animal Production Center), UNESP Botucatu-SP, Brazil. All the procedures will be performed at the Animal Facilities of the Biology Department, Biosciences Institute (BI), UNESP Rio Claro-SP, Brazil. The animals will be divided into 5 experimental groups: four control groups (CG I to CG IV), in which the mice will be exposed to: distilled water through aspersion (CG I); distilled water in "pour on" application (CG II); hydroethanolic solution 50% (v/v) through aspersion (CG III); positive control Vectra® 3D in "pour on" application (CG IV); and a treatment group (TGI), where the mice will be exposed to carvacrol through aspersion. Following exposure, all the mice will have the organs removed for morphological and histopathological analyses using bright field microscopy. Key words: toxicity; histopathology; liver; thyroid; acaricide, carvacrol. (AU)