Experimental tissue expansion induces changes in expression of procollagen I and III messenger RNA

Experimental tissue expansion was performed in nine dogs following placement of subcutaneous silicone balloons. The balloon expander was then filled with 300 ml saline immediately after implantation. Duration of expansion varied from 3 days to 124 days. Unaffected skin and skin over an empty expander served as control tissue. Dermal procollagen I and procollagen III gene expression in response to tissue expansion was investigated by dot-blot analysis using digoxigenin-labeled RNA probes complementary to either human procollagen-alpha 1(I) mRNA or procollagen-alpha 1(III) mRNA. Cross-hybridization of human probes with canine procollagen mRNA was demonstrated by Northern blot analysis. In response to the trauma of surgery, procollagen I and III mRNA transcriptions were found to be decreased significantly within the first few days after implantation. After 9 days of expansion, increased levels of procollagen I mRNA were found, while after 16 days increased levels of procollagen III mRNA were evident. The present study is the first to demonstrate changes in dermal collagen gene expression as a reaction to tissue expansion.