Effects of herbal cake-partitioned moxibustion on the expression of thyroid autophagy-related factors LC3B and Beclin-1 in rats with autoimmune thyroiditis

OBJECTIVE: To observe the anti-inflammatory effect, as well as the effect on the expression of microtubule-associated protein light chain 3B (LC3B) and Beclin-1 of herbal cake-partitioned moxibustion in rats with experimental autoimmune thyroiditis (EAT). METHODS: Female Sprague-Dawley rats were randomly divided into a normal group and a modeling group. The EAT rat model was prepared by a combination of antigen immunization plus iodine agent induction. After the model was prepared, rats in the modeling group were randomly and equally divided into a model group and a herbal cake-partitioned moxibustion group. In the herbal cake-partitioned moxibustion group, moxibustion was alternately applied to two groups of points [Dazhui (GV14)-Mingmen (GV4) and Tiantu (CV22)-Guanyuan (CV4)], and the treatment continued for 30 d. Rats in the normal and model groups were only fixed identically without intervention. Histopathological manifestations of thyroid glands were observed by hematoxylin-eosin staining; the concentrations of thyroid peroxidase antibodies (TPOAb), thyroglobulin antibodies (TGAb), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay; real-time fluorescence quantitative polymerase chain reaction and immunohistochemistry were used to detect the mRNA and protein expression of autophagy-related factors LC3B and Beclin-1 in thyroid tissue. RESULTS: There were massive follicular destruction, lymphocytic infiltration, and interstitial fibrous tissue hyperplasia of the thyroid glands in the model group. Some follicles of the thyroid glands were destroyed with few lymphocyte infiltrations and fibrous tissue hyperplasia in the moxibustion group. Compared with the normal group, the concentrations of serum TPOAb, TGAb, IL-1β, IL-6, and TNF-α were increased in the model rats (P<0.05); the mRNA and protein expression levels of LC3B and Beclin-1 in thyroid tissue were reduced in the model group (P<0.05). Compared with the model group, the concentrations of serum TPOAb, TGAb, IL-1β, IL-6, and TNF-α were reduced in the herbal cake-partitioned moxibustion group (P<0.05); the mRNA and protein expression levels of LC3B and Beclin-1 in thyroid tissue were increased in the herbal cake-partitioned moxibustion group (P<0.05). The mRNA and protein expression of LC3B and Beclin-1 in thyroid tissue was negatively correlated with the serum levels of TPOAb and TGAb. CONCLUSION: Herbal cake-partitioned moxibustion reduces the inflammatory response in the thyroid glands of EAT rats and lowers the levels of serum TPOAb and TGAb. This may be related to the regulation of mRNA and protein expression of the autophagy-associated factors LC3B and Beclin-1 in rat thyroid tissue.