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-beta 1 (TGF-beta 1) 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-beta 1. Results. Compared with group A, the expression of TGF-beta 1 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-beta 1 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-beta 1, and then caused a change in the ECM biology relevant to fibrosis and regeneration, thus affecting the wound healing process.