Changes of Transforming Growth Factor-β1 and Extracellular Matrix in the Wound Healing Process of Rats Infected With Pseudomonas aeruginosa.

OBJECTIVE:This work aims to investigate the changes of transforming growth factor-β1 (TGF-β1) and extracellular matrix (ECM) proteins in rats with chronic skin ulcers infected with Pseudomonas aeruginosa. METHODS:Forty-eight female Wistar rats, aged 8 weeks, were randomly divided into a simple cutaneous wound group (group A) and a cutaneous wound plus Pseudomonas aeruginosa inoculation group (group B). On postoperative days 1, 3, 7, and 10, hematoxylin and eosin staining, real-time polymerase chain reaction, immunohistochemistry (IHC), and enzyme-linked immunosorbent assay (ELISA) methods were used to detect the epithelization rate, the mRNA, and the protein expressions of matrix metalloproteinases (MMP) 2, MMP-9, tissue inhibitors of metalloproteinases (TIMP)-1, and TGF-β1. RESULTS:Compared with group A, the expression of TGF-β1 and the epithelization rate were delayed in group B. At 3 days postoperation, the expression of collagen III was reduced in group B. At 7 days postoperation, MMP-9 had an extremely high expression but collagen and TIMP-1 had a low expression. Seven days after being infected with Pseudomonas aeruginosa, the expression of TGF-β1 was reduced in the wounded skin of rats, and the dissolved ECM was much more than that synthesized in wounds. CONCLUSION:The authors' experiments suggest the wounded skin tissue infected with Pseudomonas aeruginosa delayed the expression of TGF-β1, and then caused a change in the ECM biology relevant to fibrosis and regeneration, thus affecting the wound healing process.