EXPERIMENTAL TISSUE EXPANSION INDUCES CHANGES IN EXPRESSION OF PROCOLLAGEN-I AND PROCOLLAGEN-III MESSENGER-RNA

Experimental tissue expansion was performed in nine dogs following pla cement of subcutaneous silicone balloons. The balloon expander was the n filled with 300 ml saline immediately after implantation. Duration o f expansion varied from 3 days to 124 days. Unaffected skin and skin o ver an empty expander served as control tissue. Dermal procollagen I a nd procollagen III gene expression: in response to tissue expansion wa s investigated by dot-blot analysis using digoxigenin-labeled RNA prob es complementary to either human procollagen-alpha 1(I) mRNA or procol lagen-alpha(III) mRNA. Cross-hybridization of human probes with canine procollagen mRNA was demonstrated by Northern blot analysis. In respo nse to the trauma of surgery, procollagen I and III mRNA transcription s were found to be decreased significantly within the first few days a fter implantation. After 9 days of expansion, increased levels of proc ollagen I mRNA were found, while after 16 days increased levels of pro collagen III mRNA were evident. The present study is the first to demo nstrate changes-in dermal collagen gene expression as a reaction to ti ssue expansion.