Effect of suture repair on expression of beta1 integrin subunit in wounded rat patellar tendon

Integrins play key roles in wound healing by mediating cell adhesion events. The purpose of this study was to determine how to change the expression level of the beta1 integrin subunit (integrin beta1) in the restoration of a tendon and to investigate the influence of suture on its expression. The lateral half of the patellar tendon in rats was transected. Half the rats were sutured immediately and the other half were left as they were. The rats were killed at 4, 7, 10, 14, 28, and 56 days postsurgery. Integrin beta1 expression in each harvested tendon was analyzed using immunohistochemistry and real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR). Integrin beta1 was immunolocalized in fibroblasts adjacent to the wound and within the repair site itself. Although immunoreactivity for integrin beta1 in the unsutured group decreased on the tenth day, that in the sutured group continued to increase. In real-time quantitative RT-PCR, integrin beta1 mRNA expression level increased in both groups, but that in the unsutured group was higher than that in the sutured group. Our study indicates that suture influences the expression and mRNA level of integrin beta1, which is associated with tendon healing.