Correlation analysis between thyroid function-related Thrβ and Thrsp genes and mechanical properties of Achilles tendon development in rats
Niu Jingwei1, Zhang Qingtao1, Wang Na1, Guan Shuo1, Wang Ying1, 2
1School of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi Province, China; 2Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan 030032, Shanxi Province, China
Abstract: BACKGROUND: Although thyroid diseases are rarely thought to be related to tendon diseases and tendon tears, increasing evidence has indicated that thyroid diseases are involved in idiopathic tendon diseases in recent years. However, there are few studies on the effects of thyroid function on the development and mechanical properties of Achilles tendon during growth and development.
OBJECTIVE: To clarify the correlation between thyroid hormone receptor beta (Thrβ) and thyroid hormone responsive (Thrsp) related to thyroid function and the mechanical properties and histological morphology of the Achilles tendon and to confirm the potential influence of thyroid function on the development of the Achilles tendon.
METHODS: The expression profiles of developmental genes in Achilles tendon were analyzed by bioinformatics, and Thrβ and Thrsp genes related to thyroid function were identified. Then the mechanical properties of the Achilles tendon of female Sprague-Dawley rats at different growth and development stages (28, 42, 56 and 70 days of age, 6 females at each stage) were measured in a tensile test. Hematoxylin-eosin staining combined with histomorphometry was used for histological evaluation and the expression levels of Thrβ and Thrsp genes were determined by fluorescence quantitative PCR. Finally, correlation analysis was conducted to determine the relationship between Thrβ and Thrsp gene expression levels and mechanical properties and histological morphology of the Achilles tendon.
RESULTS AND CONCLUSION: With the growth and development of rats, the maximum load, maximum tensile length and stiffness of the Achilles tendon did not change significantly after peaking. These mechanical properties of Achilles tendon may be related to the content, type and arrangement of collagen fibers in the tissue. Thrβ and Thrsp gene expression in the Achilles tendon at different growth stages were significantly correlated with the mechanical properties and histological scores of the Achilles tendon. These findings suggest that thyroid hormone plays a potential role in the development of the Achilles tendon and it is expected to offer new therapeutic ideas for the repair of Achilles tendon injury.
Key words: Achilles tendon development, bioinformatics, mechanical property, thyroid function, histological morphology