[Effect of Jiakangning Capsule on Thyroid Function and Akt/mTOR Signal Pathway of Graves' Disease Mice: an Experimental Study]

Abstract

Objective: To observe the improvement of thyroid function and changes of Akt, p-Akt, mammalian target of rapamycin (mTOR), and para-mTOR (p-mTOR) expression in Graves' disease (GD) mice after intervened by Jiakangning Capsule (JC), and to explore possible mechanism for JC in treating GD.

Methods: GD model was established by immunizing female BALB/c mice with thyroid stimulating hormone receptor A subunit (Ad-TSHRα-289). Totally 70 successfully modeled mice were divided into the model group (n =20), the JC intervened group (n =25), the Methimazole Tablet intervened group (n =25) according to random digit table. A normal control group (n =15) and a vehicle control group (n =20, injected with Ad-null) were also set up. Mice in the JC intervened group were administered with JC suspension at the daily dose of 1. 5 g/kg by gastrogavag. Mice in the Methimazole intervened group were administered with Methimazole suspension at the daily dose of 2. 5 g/kg by gastrogavage. Equal volume of normal saline was administered to mice in the rest 3 groups by gastrogavage. All intervention lasted for 5 weeks. Six mice were selected from each group to observe pathological changes of thyroid tissues. Serum levels of thyroxine (T4), triiodothyronine (T3), thyroid stimulating hormone (TSH), and thyrotropin receptor antibody (TRAb) were analyzed by radioimmunoassay. Expression levels of Akt, p-Akt, mTOR, and p-mTOR in thyroid tissues were etermined by Western blot.

Results: (1) The thyroid gland in the GD model group showed proliferative changes, with enlarged follicles of various sizes. Interstitial stroma was filled with blood vessels. Structures of thyroid tissues in the JC intervened group and the Methimazole intervened group were significantly restored, and follicular hyperplasia was relieved. (2) Compared with the normal control group and the vehicle control group, levels of TRAb, T4, and T3 increased; ratios of P-Akt/β-actin, p-Akt/Akt, p-mTOR/β-actin, and p-mTOR/mTOR also increased in the model group (all P <0. 01). Compared with the model group, levels of TRAb, T4, and T3 decreased in the JC intervened group and the Methimazole intervened group (P <0. 01); ratios of p-mTOR/β-actin and pmTOR/mTOR decreased in the JC intervened group (P <0.01); ratios of P-Akt/β-actin, p-Akt/Akt, p-mTOR/β-actin, and p-mTOR/mTOR decreased in the Methimazole intervened group (P <0. 05, P <0. 01). Conclusion JC could reduce thyroid hormonc levels of GD mice and lower expression levels of mTOR, and its mechanism for improving thyroid function of GD mice might be associated with this influence.