Fluoride Action Network



The objective was to investigate the effect of sodium fluoride (NaF) on the structure and function of the thyroid and ovary in albino rats.


Twenty-four female adult albino rats, 160–180 g body weight (bw), were divided into four groups of 6: the control group (I) received defluoridated water while the other 3 groups (II, III, and IV) received 5, 10, and 20 mg NaF/kg bw, respectively, for 45 days orally via the drinking water. The weights of the body, thyroid, and ovary were then examined together with the histology of the thyroid and ovary, and the levels of thyroid stimulating hormone (TSH), tri-iodo thyronine (T3), thyrox in (T4), luteinizing hormone (LH), follicle stimulating hormone (FSH), estrogen (E), and progesterone (P).


WEIGHTS: Compared to the control grou p, a decrease in body weight and an increase in thyroid gland weight were present in both the 10 (p<0.05) and 20 (p<0.001) mg NaF/kg bw groups.

HISTOLOGY: The control group rats showed the well known histological structure of the thyroid gland and ovary while the NaF-treated groups showed, in the thyroid, destruction of thyroid follicles, increased cell height, reduced colloid, and breakage of the epithelial layer. The changes in the NaF-treated groups in the ovary were disturbed ovarian follicles, dilated blood vessels, congestion of stroma, and necrotic granulosa cells with the higher dose treatment.

HORMONES: Compared to the control group, there was an increase in TSH and a decrease in T3 and T4 in the 10 (p<0.05) an d 20 (p<0.001) mg NaF/kg bw groups. For the reproductive hormones, compared to the control group, there was a decrease in LH, FSH, E, and P in the 10 (p<0.05) and 20 (p<0.001) mg NaF/kg bw groups. Conclusion: NaF administration causes hypothyroidism which affects the reproductive system of adult female albino rats (Rattus norvegicus).