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

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.

Development and application of a device for stretch-induced injury to cultured cell and testing system / 第三军医大学学报

Objective To develop a device for stretch-induced injury to cultured cells and measure the injury parameters.It makes possible to observe the changes of cell configuration and function directly after injury. Methods The device was developed based on aero-dynamical principle,and consisted of mini-type air compressor,electromagnetic valve,pressure transmitter,PGA amplifier,A/D converter and computer.The computer can accurately control the injury parameters.A new method and device were first introduced to measure the deformation rate and deformation degree of silastic membrance in the stretch induced cultured cell injury process.The device controlled by the computer was used to cause the astrocyte injury.The degree of cell injury was assessed qualitatively by electron microscopy,and quantitatively by lactate dehydrogenase(LDH) enzyme release and trypan blue staining.Results The experiment results showed that the injury of different levels could be reproduced by our device under the injury parameters we set.Conclusion The injury device and the measuring system meet the requirements of our design.The results suggested that the new device and the method were much better than those reported in foreign literature.It has the advantages of simple and convenient manipulation,high precision and real-time processing.It can be used for the cell-level experiment research.