Cardioprotective mechanism of Qixuan Yijianing formula in Graves' disease mice using miRNA sequencing approach.

Objective: To investigate the mechanism of Qixuan Yijianing (,QYN) in minimizing cardiac injury in Graves' disease (GD) mice using microRNA (miRNA) sequencing analysis.

Methods: Female BALB/c mice were randomly divided into the modeling and control groups (CG). The modeling group was established with Ad-TSHR289. Following 10 weeks of successful modeling, the mice were randomly assigned to four groups: model (MG), methimazole (MMI), QYN low-dose (LD), and high-dose (HD). After four weeks of treatment, the heart rate, heart volume, and heart index were measured, and the levels of aspartate aminotransferase (AST), lactate dehydrogenase (LDH), α-hydroxybutyrate dehydrogenase (α-HBD), creatine kinase (CK), and creatine kinase MB isoenzyme (CK-MB) in the serum were detected using a biochemical analyzer. Hematoxylin-eosin and Masson staining were used to determine histological changes in cardiac tissue. The heart tissues in the CG, MG, and HD groups were selected, and miRNA sequencing was used to identify differentially expressed miRNAs. A bioinformatics database was used to predict the target genes of differential miRNAs, and Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were conducted on the predicted target genes.

Results: As compared to the CG group, the MG group's heart rate, heart volume, heart index, AST, CK, CK-MB, LDH, α-HBD, myocardial fiber thickness, and collagen fiber significantly increased, all P < 0.01, while following QYN, these indicators improved in the HD group, all P < 0.01 or P < 0.05. Compared to the CG group, the MG group identified 151 differentially expressed miRNAs, with 42 miRNAs downregulated and 109 miRNAs upregulated; compared to the MG group, the HD group identified 70 differentially expressed miRNAs, 40 were downregulated, and 30 were upregulated. The GO functions of differential miRNA target genes are mostly enriched in cardiac development regulation, cardiac contraction control, heart rate regulation, and so on. The most enriched KEGG pathways include the mitogen-activated protein kinase, ErbB, Hippo, forkhead box protein O, and Wnt signaling pathways.

Conclusion: QYN may protect the cardiac structure and function and minimize cardiac damage caused by GD by regulating relevant target genes and signaling pathways through miRNAs which include miR-206-3p, miR-122-5p, and miR-200a-3p.