Diosgenin relieves goiter via the inhibition of thyrocyte proliferation in a mouse model of Graves' disease
Abstract
Hu CAI1, 2, 3, Zhe WANG1, Hai-qing ZHANG1, 2, 4, Fu-rong WANG5, Chun-xiao YU1, 2, 4, Feng-xia ZHANG1, 2, 6, Ling GAO1, 2, 4, Jian ZHANG7, *, Jia-jun ZHAO1, 2, 4, *
1Department of Endocrinology, Provincial Hospital affiliated to Shandong University, Ji-nan 250011, China; 2Shandong Clinical Medical Center of Endocrinology and Metabolism, Ji-nan 250011, China; 3Department of Endocrinology, Taizhou First Peoples’ Hospital, Taizhou 318000, China; 4Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Ji-nan 250011, China; 5Department of Pharmacology, Shandong University of Traditional Chinese Medicine, Ji-nan 250011, China; 6Department of Neurology, Hospital Affiliated to Shandong University of Traditional Chinese Medicine, Ji-nan 250011, China; 7Department of Pharmacy, Shandong Provincial Hospital affiliated to Shandong University, Ji-nan 250011, China
Aim: To investigate the effects of diosgenin (Dio), a naturally occurring steroid saponin, on goiter formation in a mouse model of Graves’ disease (GD) and the underlying mechanisms.
Methods: Female BALB/c mice were injected with adenovirus expressing the A subunit of thyrotropin receptor to induce GD. The mice were treated with Dio (20, 100 mg·kg-1·d-1, ip) for 12 or 24 d. The serum levels of TT4 and TRAb were examined using radioimmunoassay and electrochemiluminescence. The size and morphology of thyroid glands were examined. Thyrocyte proliferation was determined using BrdU incorporation assay. The expression of proliferation-associated proteins IGF-1, NF-κB, cyclin D1, and PCNA in thyroids was analyzed using immunohistochemistry and real-time PCR.
Results: The GD mice showed significantly high serum levels of TRAb and TT4 compared to the normal mice. Treatment of the GD mice with Dio for 24 d dose-dependently reduced the TT4 level and thyroid size, but did not affect the abnormal level of TRAb. Furthermore, Dio treatment dose-dependently reversed the morphological changes and reduced excessive thyrocyte proliferation in thyroids of the GD mice. Dio treatment also dose-dependently reduced the mRNA and protein levels of IGF-1, NF-κB, cyclin D1, and PCNA in thyroids of the GD mice.
Conclusion: Dio relieves goiter in a mouse model of GD through the inhibition of thyrocyte proliferation. The mechanisms involve the suppression of IGF-1, NF-κB, cyclin D1, and PCNA expression.
Keywords: diosgenin; saponin; thyroid gland; goiter; Graves’ disease; TRAb; TT4; IGF-1; NF-κB; cyclin D1; PCNA
Dr Shu WANG (Ruijin Hospital of Shanghai Jiao Tong University, Shanghai, China) assisted with the delivery of the adenovirus. This work was supported through the National Natural Science Foundation of China (30901461, 81070625 and 81101590), the Natural Science Foundation of Shandong Province (2009CM005 and BS2010YY049) and the Jinan Self-renovation Plan for Colleges and Universities and Scientific Research Institutes (200906012) of China.
* To whom correspondence should be addressed.
E-mail sdjnzhjx@163.com (Jian ZHANG); jjzhao@medmail.com.cn (Jia-jun ZHAO)
Received 2013-07-10 Accepted 2013-08-22
Keywords:
1Department of Endocrinology, Provincial Hospital affiliated to Shandong University, Ji-nan 250011, China; 2Shandong Clinical Medical Center of Endocrinology and Metabolism, Ji-nan 250011, China; 3Department of Endocrinology, Taizhou First Peoples’ Hospital, Taizhou 318000, China; 4Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Ji-nan 250011, China; 5Department of Pharmacology, Shandong University of Traditional Chinese Medicine, Ji-nan 250011, China; 6Department of Neurology, Hospital Affiliated to Shandong University of Traditional Chinese Medicine, Ji-nan 250011, China; 7Department of Pharmacy, Shandong Provincial Hospital affiliated to Shandong University, Ji-nan 250011, China
Aim: To investigate the effects of diosgenin (Dio), a naturally occurring steroid saponin, on goiter formation in a mouse model of Graves’ disease (GD) and the underlying mechanisms.
Methods: Female BALB/c mice were injected with adenovirus expressing the A subunit of thyrotropin receptor to induce GD. The mice were treated with Dio (20, 100 mg·kg-1·d-1, ip) for 12 or 24 d. The serum levels of TT4 and TRAb were examined using radioimmunoassay and electrochemiluminescence. The size and morphology of thyroid glands were examined. Thyrocyte proliferation was determined using BrdU incorporation assay. The expression of proliferation-associated proteins IGF-1, NF-κB, cyclin D1, and PCNA in thyroids was analyzed using immunohistochemistry and real-time PCR.
Results: The GD mice showed significantly high serum levels of TRAb and TT4 compared to the normal mice. Treatment of the GD mice with Dio for 24 d dose-dependently reduced the TT4 level and thyroid size, but did not affect the abnormal level of TRAb. Furthermore, Dio treatment dose-dependently reversed the morphological changes and reduced excessive thyrocyte proliferation in thyroids of the GD mice. Dio treatment also dose-dependently reduced the mRNA and protein levels of IGF-1, NF-κB, cyclin D1, and PCNA in thyroids of the GD mice.
Conclusion: Dio relieves goiter in a mouse model of GD through the inhibition of thyrocyte proliferation. The mechanisms involve the suppression of IGF-1, NF-κB, cyclin D1, and PCNA expression.
Keywords: diosgenin; saponin; thyroid gland; goiter; Graves’ disease; TRAb; TT4; IGF-1; NF-κB; cyclin D1; PCNA
Dr Shu WANG (Ruijin Hospital of Shanghai Jiao Tong University, Shanghai, China) assisted with the delivery of the adenovirus. This work was supported through the National Natural Science Foundation of China (30901461, 81070625 and 81101590), the Natural Science Foundation of Shandong Province (2009CM005 and BS2010YY049) and the Jinan Self-renovation Plan for Colleges and Universities and Scientific Research Institutes (200906012) of China.
* To whom correspondence should be addressed.
E-mail sdjnzhjx@163.com (Jian ZHANG); jjzhao@medmail.com.cn (Jia-jun ZHAO)
Received 2013-07-10 Accepted 2013-08-22