[Study of mechanism on loss of some components from basement membrane in epithelial-interstitial junction in cutaneous pseudoepitheliomatous hyperplasia lesion].
OBJECTIVE
To investigate the relationship between the formation of pseudoepitheliomatous hyperplasia (PEH) and the mechanism of loss of some components from the basement membrane in epithelial interstitial junction (EIJ) in the treatment of cutaneous wounds, when formation of PEH lesion was induced.


METHODS
Morphological change in epithelial tissue was observed with histopathologic method and electronic microscopy in 11 specimens of PEH lesions and 6 specimens of normal skin adjacent to PEH (PEH-N) from 11 patients with injured skin. The expression characteristics and distribution of pan-cytokeratin (p-CK), matrix metalloproteinase-2 (MMP-2), MMP-3, MMP-9, proliferating cell nuclear antigen (PCNA), epithelial cadherin(E-Cad) and beta-catenin(beta-Cat) in EMJ were detected with immunohistochemical methods.


RESULTS
Epithelial cells expressing P-CK presented squamous epithelialization and extended into deep layer of mesenchyma. In epithelium-mesenchyma junction, where IV type collagen and laminin were weakly expressed, the protein contents of p-CK, E-Cad, MMP-2, MMP-3 MMP-9 were decreased, whilst the immunochemical staining of beta-Cat and PCNA was apparently increased. In the junction, epithelial basal cells were observed to migrate and to depart from basal membrane; epithelial islands and isolated epithelial cells expressing p-CK in mesenchyma could be observed. Ultrastructural observation revealed deformation of epithelial basal cells, increment of nucleus/cytoplasm ratio, loosened intercellular junctions, decrement of electronic density of BM and derangement of BM structure could be observed.


CONCLUSIONS
Reduction in the capability of epithelial basal cells adhesion, differentiation and formation of basement membrane and cytokeratin in PEH associated with wound may be the crucial cause which controls epithelial cells migration into mesenchyma. That the contents of ColIV and LN were decreased may not be associated with MMPs, but with enhancement of the ratio of beta-Cat/E-Cad signal might be the important mechanism of dedifferentiation of epithelial basal cells and the loss of ability of structure formation and cellular migration.
Jiang
Du-yin
DY
Key Laboratory of Wound Repair, 304th Hospital of PLA, Beijing, 100037, China.
Fu
Xiao-bing
XB
Sheng
Zhi-yong
ZY
Cheng
Wei
W
Zhou
Gang
G
Sun
Tong-zhu
TZ
D001485:Basement Membrane / Q000737:chemistry / Q000473:pathology*; D015820:Cadherins / Q000032:analysis; D003598:Cytoskeletal Proteins / Q000032:analysis; D004848:Epithelium / Q000737:chemistry / Q000473:pathology*; D006801:Humans; D006965:Hyperplasia; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis; D020782:Matrix Metalloproteinases / Q000032:analysis; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D012867:Skin / Q000737:chemistry / Q000473:pathology; D015534:Trans-Activators / Q000032:analysis; D051176:beta Catenin
C495270:CTNNB1 protein, human; D015820:Cadherins; D003598:Cytoskeletal Proteins; D018809:Proliferating Cell Nuclear Antigen; D015534:Trans-Activators; D051176:beta Catenin; D007633:Keratins; D020782:Matrix Metalloproteinases