[Relationship between keloid proliferation and apoptosis of epithelial cell with destruction of structure and function of skin appendages].

OBJECTIVE

To investigate the relationship between keloid proliferation and destruction of skin appendages (SAs).

METHODS

Pathological biopsies of keloids were derived from 17 patients who underwent scar resection. All samples were divided into 4 groups: infiltrating growth locus of keloids (K-I, n = 9), proliferative keloids (K-P, n = 17), atrophic keloids (K-A, n = 10), and edging normal skin (K-N, n = 6). Normal skin derived from thorax of patients was used as control (NS, n = 6). The density of SAs and the expressive characteristics of pan-cytokeratin (CKp), cytokeratin 19 (CK19), secretory component of glandular epithelium (SC), proliferating cell nuclear antigen (PCNA), and apoptosis related proteins (Bcl-2 and Bax) were observed with immunohistochemical method.

RESULTS

Compared with K-N and NS, the density of SAs expressing CKP and SC in keloids was apparently decreased, and remnant of CKp protein was observed after the disappearance of SAs structures. Protein expression of Bax was increased in epithelial cells of most SAs. SAs containing positive immunostaining signals of Bcl-2, PCNA and CK19 exhibited squamous epithelization and abnormal structure. The structure of SAs underwent 3 morphological stages: infiltrating, proliferating, and maturing. In correspondence to each stage, SAs underwent proliferation, structural destruction, and fibrosis which were caused by cellular migration, inflammatory reaction, and vascular occlusion respectively.

CONCLUSION

Abnormal proliferation of epithelial cells and their structural destruction of SAs may be associated with tissue fibrosis in keloid lesion.