Objective:

2

To explore the mechanism of

Radix Scrophulariae

(RS) extracts in the treatment of hyperthyroidism rats by regulating proliferation

apoptosis

and autophagy of thyroid cell through the mammalian sterile 20-like kinase 1 (MST1)/Hippo pathway.

Methods:

2

Twenty-four rats were randomly divided into 4 groups according to a random number table: control

model group

RS

and RS+Hippo inhibitor (XMU-MP-1) groups (

n

= 6 per group). Rats were gavaged with levothyroxine sodium tablet suspension (LST

8 μg/kg) for 21 days except for the control group. Afterwards

rats in the RS group were gavaged with RS extracts at the dose of 1

350 mg/kg

and rats in the RS+XMU-MP-1 group were gavaged with 1

350 mg/kg RS extracts and 1 mg/kg XMU-MP-1. After 15 days of administration

thyroid gland was taken for gross observation

and histopathological changes were observed by hematoxylin-eosin staining. The structure of Golgi secretory vesicles in thyroid tissues was observed by transmission electron microscopy. The expression of thyrotropin receptor (TSH-R) was observed by immunohistochemistry. Terminal-deoxynucleoitidyl transferase mediated nick end labeling assay was used to detect cell apoptosis in thyroid tissues. Real-time quantity primer chain reaction and Western blot were used to detect the expressions of MST1

p-large tumor suppressor gene 1 (LATS1)

p-Yes1 associated transcriptional regulator (YAP)

proliferating cell nuclear antigen (PCNA)

G

1

/S-specific cyclin-D1 (Cyclin D1)

B-cell lymphoma-2 (Bcl-2)

Caspase-3

microtubule-associated proeins light chain 3 Ⅱ/Ⅰ (LC3-Ⅱ/Ⅰ)

and recombinant human autophagy related 5 (ATG5). Thyroxine (T4) level was detected by enzyme-linked immunosorbent assay.

Results:

2

The thyroid volume of rats in the model group was significantly increased compared to the normal control group (

P

<

0.01)

and pathological changes such as uneven size of follicular epithelial cells

disorderly arrangement

and irregular morphology occurred. The secretion of small vesicles by Golgi apparatus was reduced

and the expressions of receptor protein TSH-R and T4 were significantly increased (

P

<

0.01)

while the expressions of MST1

p-LATS1

p-YAP

Caspase-3

LC3-Ⅱ/Ⅰ

and ATG5 were significantly decreased (

P

<

0.01). The expressions of Bcl-2

PCNA

and cyclin D1 were significantly increased (

P

<

0.01). Compared with the model group

RS extracts reduced the volume of thyroid gland

improved pathological condition of the thyroid gland

promoted secretion of the secretory vesicles with double-layer membrane structure in thyroid Golgi

significantly inhibited the expression of TSH-R and T4 levels (

P

<

0.01)

upregulated MST1

p-LATS1

p-YAP

Caspase-3

LC3-Ⅱ/Ⅰ

and ATG5 expressions (

P

<

0.01)

and downregulated Bcl-2

PCNA

and Cyclin D1 expressions (

P

<

0.01). XMU-MP-1 inhibited the intervention effects of RS extracts (

P

<

0.01).

Conclusion:

2

RS extracts could inhibit proliferation and promote apoptosis and autophagy in thyroid tissues through MST1/Hippo pathway for treating hyperthyroidism.