【Animal Modeling】-Analysis of Thyroid Function in Chronic Intermittent Hypoxia Model Rats

  Objective To explore the relationship between obstructive sleep apnea hypopnea syndrome and thyroid function in a rat model of chronic intermittent hypoxia.

  Methods SD rats were divided into control group, CIH group and reoxygenation (RH) group. A hypoxic chamber was used to establish a CIH animal model, and the CIH model was identified. Expression levels of thyrotropin releasing hormone (TRH), thyroid stimulating hormone (TSH), triodothyronine (T3) and thyroxine (T4); HE staining and nails Aniline blue staining was used to observe the pathological changes of thyroid tissue in each group; electron microscope was used to observe the changes of ultrastructure of thyroid tissue in each group.

  Results The blood oxygen saturation of the rats in the CIH group and the RH group was 70%-92%, and the arterial oxygen partial pressure was 60.7-80.1 mmHg, which was close to the pathophysiological characteristics of obstructive sleep apnea hypopnea syndrome. Therefore, the CIH animal model was established. success. Compared with the control group, the expression levels of TRH, TSH, T3 and T4 in the serum of the rats in the CIH group were significantly decreased (all P<0.05), and the thyroid mass was significantly increased (P<0.01). The expression levels of TRH, TSH, T3 and T4 were significantly increased (all P<0.05), and the thyroid mass was decreased (P≤0.05). HE staining and toluidine blue staining showed that the thyroid tissue of rats in the control group had complete thyroid follicles; the normal follicular structure of the thyroid gland of the rats in the CIH group was lost, some follicular cells showed vacuoles, and the basal nucleus was dark; Murine thyroid tissue showed normal follicular architecture, but some follicular cells remained vacuolated with dark nuclei. Electron microscope observation found that the thyroid gland of the control group had normal follicular cells; the thyroid follicular cells of the CIH group had contracted nuclei, increased heterochromatin, and lost matrix; the thyroid part of the RH group had intact follicles cell structure.

  Conclusion CIH can lead to disorder of thyroid function regulation in rats, and resumption of oxygen inhalation can partially restore thyroid function to normal.