Histological and genetic changes induced by extracorporeal shockwave therapy after rotator cuff repair in a rat model with tears

Abstract

The histological and genetic changes associated with significant tendon-to-bone differences after extracorporeal shockwave therapy (ESWT) are unknown. This controlled laboratory study investigated the histological and genetic changes in the rotator cuff induced by ESWT. Twenty-two retired male Wistar rats were induced with left supraspinatus tendon ruptures. Three weeks later, rotator cuff repair was performed. One week post-repair, the rats were randomly assigned into either the ESWT or control group, with 11 rats in each group. Compared with the control group, the ratio of cellularity was significantly lower, and that of collagen fiber orientation was significantly higher in the ESWT group. The number of blood vessels and the total histological scores were not significantly different between the two groups. Real-time polymerase chain reaction analysis revealed that the mRNA expressions of CCN2 and SCX were significantly higher in the ESWT group than in the control group. No statistically significant differences were found between the SOX9 and Tnmd expressions. ESWT induces histological changes and increases the messenger RNA expressions of CCN2 and SCX in rotator cuff repair of chronic tears in rats. ESWT is a potential method for promoting histological and cytological changes associated with improving the mechanical strength of rotator cuff repair.