Alterations in atrial ion channels and tissue structure promote atrial fibrillation in hypothyroid rats
| Autor: | Jiawei Zhang, Xinbo Zhao, Hongwei Zhao, Zhaoguang Liang, Hai Cang, Yi-Lun Zou, Jianqiang Li, Dingyu Wang, Zhaorui Liu, Yue Li, Fengxiang Yun |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Male
endocrine system medicine.medical_specialty Potassium Channels endocrine system diseases Endocrinology Diabetes and Metabolism medicine.medical_treatment 030209 endocrinology & metabolism 03 medical and health sciences 0302 clinical medicine Endocrinology Hypothyroidism Diabetes mellitus Internal medicine Atrial Fibrillation Medicine Animals Euthyroid Heart Atria Rats Wistar Triiodothyronine Voltage-dependent calcium channel business.industry Thyroid Thyroidectomy Atrial fibrillation medicine.disease medicine.anatomical_structure Echocardiography 030220 oncology & carcinogenesis business hormones hormone substitutes and hormone antagonists Hormone |
| Zdroj: | Endocrine. 65(2) |
| ISSN: | 1559-0100 |
| Popis: | It is well known that hyperthyroidism is associated with atrial fibrillation (AF); however, the relationship between hypothyroidism and AF remains controversial. Hypothyroidism was established in rats by two methods: methimazole-induced (MMI) and thyroidectomy (TX). MMI model includes control (n = 10), MMI (n = 10), and MMI + L-thyroxine (T4, n = 10). Methimazole was given intragastrically in MMI and MMI + T4 for 12 weeks, and T4 was added intragastrically in MMI + T4 at week 5. TX model includes sham (n = 10), TX (n = 10), and TX + T4 (n = 10). Four weeks after surgery, rats in TX + T4 received T4 for 8 weeks. Triiodothyronine (T3), T4, and thyroid-stimulating hormone (TSH) were measured. Electrophysiology, tissue structure and function, and protein levels of potassium and L-type calcium channels were assessed in the atria. Severe changes in the atrial structure of hypothyroid rats were observed. Compared with euthyroid rats, atrial effective refractory period (AERP) in hypothyroid rats was significantly shortened; accordingly, inducibility and duration of AF were considerably increased. Protein levels of minK, Kv1.5, Kv4.2, Kv4.3, Kv7.1, and Cav1.2 were upregulated in hypothyroid rats, whereas there was only a tendency toward increased Kir2.1. Kv11.1 was statistically upregulated in the MMI model and had an increasing tendency in the TX model. Conversely, Kir3.1 and Kir3.4 were downregulated in hypothyroid rats. The above changes could be partially inhibited by T4 treatment. AERP shortening due to altered protein levels of ion channels and atrial structural changes increased the susceptibility to AF in hypothyroidism. Thyroid replacement therapy could prevent electrical and structural remodeling under hypothyroid condition. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink