THE EFFECTS OF CARBOFURAN ON THYROID GLAND OF FEMALE RATS
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Date
2012
Authors
NURHAFIZAH, GHANI
Journal Title
Journal ISSN
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Publisher
Pusat Pengajian Sains Perubatan Universiti Sains Malaysia
Abstract
Carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methylcarbamate) is a
carbamate pesticide that is commonly used in paddy fields for rodent control in
Malaysia. Carbofuran exerts various adverse effects to the non-target organisms.
Although the toxicity effect of carbofuran has been widely explored, its effect on the
thyroid gland in many species including human is still questionable. The aim of this
study is to investigate the histopathological changes, histomorphometric alteration of the
thyroid gland, thyroid activation index and thyroid stimulating hormone level of the
female rats after exposure to carbofuran. This experiment was a randomised control trial
study. Twenty female Sprague-Dawleys rats were randomly allocated into control, low
dose, medium dose and high dose groups that were exposed to normal saline, 0.6 mg/kg
carbofuran, 1.2 mg/kg carbofuran and 2.4 mg/kg carbofuran respectively. The exposure
was done via oral gavage once daily for 28 days. Body weight and toxicity were
monitored daily. Sections of thyroid gland were sampled by adopting the systematic
uniform random sampling method and stained with hematoxylin & eosin dyes. Besides
qualitative analysis, semi-quantitative analysis was also done to assess the severity of
histopathological changes. The serum thyroid stimulating hormone was measured by
ELISA method. Histopathological assessments showed abnormal features of thyroid in
all the groups such as the presence of desquamated follicular cells into follicular lumen,
damaged follicles, increased interstitial space, abortive follicles, hyperplastic follicles
and hydropic degeneration in all groups. However, only the severity score of abortive
follicles was significantly higher in carbofuran treated groups compared to control (p <
0.05). Whereas for the histomorphometric features, the follicles circumference was
found to be significant (p < 0.05) compared to follicle area, colloid area and
circumference, follicular cell height and follicular cell area. The thyroid activation index
and thyroid stimulating hormone were found not to be significant. This study shows that
carbofuran could induce the histopathological changes and histomorphometric alteration
of thyroid gland in female rats thus the toxicity effect of carbofuran should be explored
further.
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CLINICAL ANATOMY