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) remain unknown. This controlled laboratory study investigated the histological and genetic changes induced by ESWT in the rotator cuff. Left supraspinatus tendon ruptures were induced in 22 retired male Wistar rats. 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 per group. Compared with the control group, the ratio of cellularity was significantly lower, while 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 significantly higher messenger RNA (mRNA) expressions of CCN2 and SCX in the ESWT group than in the control group. No statistically significant differences in mRNA expression were found between the SOX9 and Tnmd. ESWT induces histological changes and increases the mRNA expressions of CCN2 and SCX in the repair of chronic rotator cuff tears in rats. These findings highlight the potential of ESWT to promote histological and molecular changes associated with tendon-to-bone healing.