OBJECTIVETo investigate the expression of Tenascin-C mRNA in keloids and hypertrophic Total RNA was isolated from normal adult skin. A cDNA fragment (base 5941-6481bp) of the scars.

METHODSfull-length human Tenascin-C cDNA was synthesized by polymerase chain reaction and subcloned in pGEM-T-easy. Dioxygen-labeled anti-sense and sense probes were synthesized by using a Sp6/T7 RNA synthesis kit in the present of Dig-UTP in vitro. The samples were taken from keloids in 10, hypertrophic scars in 10 and normal adult skin in 5. The hybridization was performed with 4% paraformaldehyde-fixed and wax-embedded sections to detect the Tenascin-C mRNA.

RESULTSThe Tenascin-C mRNA was negative in the normal adult epidermis and weakly located in the fibroblasts of the papillary dermis and the epidermal adnexa. In all of the 10 keloid specimens, the Tenascin-C mRNA was positive throughout the epidermis and widely distributed in the dermis included in the fibroblasts, endothelial cells and epidermal adnexa. In the specimens of the 3 hypertrophic scars,the Tenascin-C mRNA was also positive in the epidermis, but in the other 7 cases, it became negative. In the dermis of the hypertrophic scar,the Tenascin-C mRNA was weaker than that in the keloid, but stronger than that in the normal skin.

CONCLUSIONSThe expression of Tenascin-C mRNA is markedly enhanced in the keloids.