Abstract: Objective  To explore the changes in adipokines and inflammatory factors in rats under subclinical hypothyroidism conditions. Methods  This study established an animal model of thyroidectomy to simulate the characteristics of subclinical hypothyroidism patients in clinical practice. Combined with molecular biology methods, the expression changes of key molecules in thyroid biology processes and the relationship between hormones and inflammatory factors secreted by fat and liver were investigated. Results  The results showed that the serum leptin content in the  subclinical hypothyroidism model group was significantly higher than that in the normal group (P<0.001), and the adiponectin content was significantly higher than that in the normal group (P<0.01). In addition, the levels of interleukin-6 ( IL-6 )and tumor necrosis factor-α (TNF-α) in serum were significantly higher than those in the normal group (P<0.05). The levels of IL-6 and TNF-α in the liver were significantly higher than those in the normal group (P<0.01). The Western blotting of adipose tissue showed that the expression levels of thyroid hormone receptor α(TRa), TRβ and TR in the subclinical hypothyroidism model group increased compared to the normal group, and the elevated expression of thyrotropin receptor (TSHR) was observed. Conclusion  This study preliminarily confirms that subclinical hypothyroidism leads to abnormal fat accumulation and distribution in rats, which in turn induces disorders in leptin and adiponectin secretion, accompanied by elevated levels of inflammatory factors such as IL-6 and TNF-α. These changes participate in the regulation of local energy metabolism by modulating the secretion of thyrotropin-releasing hormone (TRH) and thyroid stimulating hormone (TSH), laying an experimental foundation for elucidating the intrinsic relationship between subclinical hypothyroidism and obesity.

Key words: subclinical hypothyroidism, hypothyroidism, inflammatory factors, leptin, obesity, adiponectin