# Establishment and investigation of a surgical model of hypothyroidism in Wistar rats

## TL;DR

This study created a reliable rat model of hypothyroidism through thyroid gland removal and confirmed its stability over time.

## Contribution

The study establishes a stable surgical hypothyroidism model in Wistar rats for future research.

## Key findings

- Surgical thyroid removal led to significantly lower FT4 and FT3 levels and higher TSH levels postoperatively.
- The model showed stable hypothyroidism indicators over 90 days post-surgery.
- Thyroglobulin levels were significantly reduced in the surgical group by day 60.

## Abstract

The purpose of this study was to investigate the surgical model of hypothyroidism in rats and the feasibility and stability of the model.

Forty-eight adult male Wistar rats were randomly divided into 12 sham-operated rats (control group) and 36 operated rats (18 rats in the group with total thyroidectomy and 18 rats in the group with subtotal thyroidectomy). Thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) serum concentrations were measured prior to surgery and on postoperative days 14, 28 and 90; blood calcium (Ca), blood phosphorus (P), and parathyroid hormone (PTH) concentrations were measured on postoperative day 10; and thyroglobulin (Tg) concentrations were measured on postoperative day 60. The postoperative behavioral status of the rats was comprehensively evaluated on the basis of behavioral indicators.

There was no significant difference in preoperative TSH, FT4, or FT3 between the control and surgical groups (p > 0.05). On postoperative day 10, there were no significant differences in Ca, P, or PTH levels among the groups (p > 0.05). On postoperative days 14, 28 and 90, the TSH level was greater, whereas the FT4 and FT3 levels were lower in the surgical group (p < 0.05). On the 60th postoperative day, the Tg was significantly lower in the surgical group (p < 0.05).

Surgical removal of the thyroid gland can be used to successfully establish a hypothyroid rat model that is stable and reliable and can provide a model basis for hypothyroidism-related research.