HISTOLOGY AND HISTOPATHOLOGY

Cellular and Molecular Biology

Histopathological features and modulation of type lV collagen expression induced by Pseudomonas aeruginosa lipopolysaccharide (LPS) and porins on mouse skin

A. Baroni1, F. Gorga2, A. Baldi3, B. Perfetto2, I. Paoletti2, A. Russo1, L. Lembo1 and F. Rossano2

1Institute of Dermatology, Faculty of Medicine, Second University of Naples, Naples, Italy and
2Institute of Microbiology, Faculty of Medicine, Second University of Naples, Naples, Italy and
3Laboratory of Cell Metabolism and Pharmacokinetics, CRS, Regina Elena Cancer Institute, Roma, Italy

Offprint requests to: Dr. Fabio Rossano, Institute of Microbiology, Faculty of Medicine, Second University of Naples, Larghetto s. Aniello a Caponapoli n 2, 80138 Naples, Italy. Fax: +39 81-5665661. e-mail: fabio.rossano@unina2.it

 

Summary. Background: Pseudomonas aeruginosa (P. aeruginosa) is responsible for serious infections in the immunocompromised host. Many skin lesions induced by P. aeruginosa have been described. Few investigations have been performed on the local action of P. aeruginosa components. Objectives: To shed light on the "in vivo" activity of lipopolysaccharide (LPS) and porins extracted from P. aeruginosa, by verifying their effects after inoculation in mouse skin through the observation of histological changes and immunohistochemical expression of collagen IV. Results: Both substances were able to induce a similar inflammatory process and a characteristic reversible change in collagen IV distribution. Interestingly, a fibroblast increase was observed at 24 h in the skin treated with porins, while it appeared later in the skin treated with LPS. Besides these changes, porins particularly increased collagen edema, together with disgregation of hypodermal structures. Moreover "in vitro", porins were able to stimulate fibloblasts 3T3 to convert 72 kDa type IV collagenase into the activated 62 kDa form and to release the 92 kDa collagenase. Conclusion: LPS and porins, released by Gram-negative bacteria during cell growth and lysis, interact with the host at target cells, such as keratinocytes, fibroblasts and immunocompetent cells, thus contributing significantly to the pathogenesis of P. aeruginosa skin infections. Histol. Histopathol. 16, 685-692 (2001)

Key words: Bacterial components, Pseudomonas aureginosa, Inflammation, Type IV collagen

DOI: 10.14670/HH-16.685