Objective To investigate the relationship between keloid proliferation and destruction of skin appendages(SAs). Methods Pathological biopsies of keloids were derived from 17 patients whounderwent 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), cytokeratin19 (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 cellsof most SAs. SAs containing postive 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, nflammatory reaction, and vascular occlusion respectively. Conclusion Abnormal proliferation of epithelial cells and their structural destruction of SAs may beassociated with tissue fibrosis in keloid lesion.
Objective To investigate the feasibility of differentiation of the marrow mesenchymal stem cells (MSCs) into the cells of the skin appendages andthe mechanism of their involvement in the wound healing. Methods The bone marrow was collected from Wistar rats by the flushing of the femurs, MSCs were isolated and purified by the density gradient centrifugation. Then, the MSCs were amplified and labelled with 5-bromo-2′-deoxyuridine (BrdU). The full-thickness skin wounds with an area of 1 cm×1 cm were made on the midback of the homogeneous male Wistar rats. At the same time, 1×106/ml BrdU-labelled MSCs were infused from thepenile vein. The specimens were harvested from the wound tissues on the 3rd dayand the 7th day after operation and were immunohistochemically stained by either BrdU or BrdU and pan-keratin. Results The BrdU positive cells appeared in thehypodermia, the sebaceous glands, and the hair follicles of the wounds, as wellas the medullary canal of the femurs. The double-staining showed the BrdU positive cells in the sebaceous glands and the hair follicles of the wounds expressedpan-keratin simultaneously. Conclusion During the course of the wound healing, MSCs are involved in the wound repair and can differentiate into the cells ofthe skin appendages under the microenvironment of the wound.