Matrix Metalloproteinase(MMP)-2 Expression Related to Stretch Injury of the Anterior Cruciate Ligament in the Knee

Woo, Young Kyun; Song, Seok Whan; Kwon, Soon Yong; Lee, Hwa Sung; Kim, Young Hoon

Abstract

PURPOSE: Tissue remodeling is essential for the natural healing of damaged tissue. The matrix metalloproteinases (MMPs) that degrade the extracellular matrix to play a central role in this process. This study was designed to examine the basic relationship between MMP-2 and anterior cruciate ligament (ACL) injury.
MATERIALS AND METHODS
After the femur-ACL-tibia complex was harvested from rats, the continuous release of MMP-2 in the stretch group was evaluated. The complexes were divided into three groups. To stretch the complexes, in group I, 5 and 12 N weights were used for 10, 30, and 60 minutes. In group II, 5 and 15 N weights were used for 5, 10, 30, 60, and 120 minutes. And in group III, 5, 8, 10, 12, and 15 N weights were used for 30 and 60 minutes. MMP-2 activity was evaluated using 0.05% gelatin zymography.
RESULTS
MMP-2 was expressed and the signal intensity was increased according to the stretch duration and magnitude. In the tissue analysis, active MMP-2 was markedly present and the expression was increased in response to the stretch in the supernatant samples.
CONCLUSION
MMP-2 was released immediately after ligament injury and its activity was increased in proportion to the stretch duration and magnitude. It is believed that MMP-2 expression plays an important role in the remodeling process after an ACL injury.