RESUMEN
BACKGROUND/AIMS: Amiodarone, a thyroid hormone-like molecule, can induce dyslipidemia and thyroid dysfunction. However, the effects of dronedarone on lipid metabolism and of both dronedarone and amiodarone on thyroid function and lipid metabolism remain unknown. METHODS: Fifty male Sprague-Dawley rats were randomly divided into 5 groups (10 in each group): normal control (NC), amiodarone-treated (AMT), dronedarone-treated (DRT), rats treated with amiodarone combined with polyene phosphatidylcholine (AC), and rats treated with dronedarone combined with polyene phosphatidylcholine (DC). Rats were given amiodarone (120 mg/kg/d), dronedarone (120 mg/kg/d), and polyene phosphatidylcholine (200 mg/kg/d) for 13 weeks. At the end of weeks 4, 8, 12, and 13, plasma-free triiodothyronine (FT3), free thyroxine (FT4), triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) were determined. At the end of this protocol, rats were sacrificed and the thyroid glands were isolated, weighed, and examined histopathologically. The protein expression of Bcl-2 was measured by immunochemical staining. The mRNA expression of thyroglobulin (Tg), type-1 deiodinase (D1), and thyroid peroxidase (TPO) were detected by polymerase chain reaction (PCR). RESULTS: Compared with the NC group, FT3 and FT4 levels in the DRT and DC groups significantly increased at week 4 but declined thereafter. The AMT and AC groups had lower FT3 levels but comparable FT4 levels. The levels of TG, LDL-c, and HDL-c in the NC group were lower than those in the other groups whereas the LDL-c/HDL-c ratio was lowest in the AMT group. Bcl-2 expression significantly increased in the DRT group. The mRNA expression of Tg increased whereas the mRNA expression of D1 decreased. Dronedarone induced hyperthyroidism at the early stage and hypothyroidism at the late stage whereas amiodarone only caused hypothyroidism. CONCLUSION: Both dronedarone and amiodarone can induce dyslipidemia and increase the levels of TC, LDL-c, and HDL-c, and these effects may be associated with thyroid dysfunction.