Objective: To investigate the expression of endogenetic matrix metalloproteinases-9 (MMP-9) and transforming growth factor-beta(TGF-beta) and their role in the wound healing of blast injury.
Methods: Rat models of blast injury under a humid and hot environment were established and the effusion from the wound surface was collected at 4, 24, 48 h and 5, 7, 14, 21 and 28 days after injury, respectively. The contents of MMP-9 and TGF-beta in the effusion of the wound were measured by zymography and enzyme-linked immunosorbent assay (ELISA), respectively.
Results: During the wound healing of blast injury, MMP-9 and TGF-beta exhibited changes that followed a regular pattern, both reaching the peak value at 48 h after the injury. TGF-beta content reached the another peak on day 7. TGF-beta value and MMP-9 contents decreased in the second week after injury and their reduction was no longer parallel. Administration of tissue inhibitor of metalloproteinase (TIMP) in the early phase of injury showed no obvious effect, but during the 2 weeks after the injury, its administration caused decrease in MMP-9 content and increase in TGF-beta content in the effusion.
Conclusions: In the early phase of wound healing, the elevation of MMP-9 and TGF-beta accelerated cell migration to promote the clearance of the inflammatory necrosis tissues, which might be one of the wound healing mechanisms. But overexpression of MMP-9 in the wound may hinder wound healing, and appropriate use of TIMP can accelerate the delayed wound healing.