Thermal Preconditioning May Prevent Tendon Adhesion by Up-Regulating HSP72 in Rats

Abstract

The study aims to determine the effects of thermal preconditioning on tendon adhesion by regulating the expression of heat shock protein 72 (HSP72) in rat models. Sixty male Wistar rats were collected and randomly assigned into the thermal preconditioning and control groups. During the 4th and 8th weeks following surgery, 15 rats were sacrificed in each period respectively, and their tendon adhesion was observed and evaluated. Biomechanical testing was performed to measure the tensile strength and gliding distance of tendons. Hematoxylin-eosin (HE) was used to observe the morphological structure of the tendons. Immunohistochemical staining, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were used to detect the HSP72, fibroblast growth factor-2 (FGF-2), fibroblast growth factor receptor-1 (FGFR-1), β-catenin, epithelial cell adhesion molecule (EPCAM), Tenomodulin and scleraxis protein expressions. Pearson correlation analysis was applied to analyze the correlation between HSP72 expression and tendon adhesion. At the 4th week after surgery, we found no differences in the tendon adhesion scores or mRNA and protein expressions of HSP72 between the thermal preconditioning and control groups. However, after the 8th week after surgery, the thermal preconditioning group had a lower tendon adhesion score and higher mRNA and protein expressions of HSP72 than the control group. During the same period, we found longer gliding distance and higher expression levels of FGF-2, FGFR-1, β-catenin, Tenomodulin and scleraxis, but lower EPCAM expression in the thermal preconditioning group. Pearson correlation analysis indicated that HSP72 mRNA and protein expression levels were negatively correlated with tendon adhesion. These findings provide evidence that thermal preconditioning may alleviate tendon adhesions via upregulation of HSP72 expression.