Identification of genes induced by rapid intraoperative tissue expansion in mouse skin

A method of rapid skin stretching, i.e. hemispherical load cycling with an inflated subcutaneous silicone balloon (Rapid Intraoperative Tissue Expansion or RITE), permits the surgeon to rapidly elongate skin and create a flap of greater length for reconstructive plastic surgery. We have previously developed an experimental mouse model to evaluate RITE, and have shown that rapid stretching prevents ischemia and significantly reduces necrosis. Although the advantages of RITE have been demonstrated both clinically and experimentally, the cellular and molecular mechanisms underlying these benefits were unknown. In the study reported here, we used differential display reverse transcription polymerase chain reaction to identify genes that are specifically induced by RITE. Among four differential gene fragments, the expression of one was confirmed by Northern blot hybridization. The cDNA fragment was extended and the resultant sequence analyzed to reveal induction of truncated long interspersed nucleotide element 1 (LINE-1 or L1). Truncated L1 elements are located inside introns of many genes and among these genes myotubularin and insulin I are known to regulate cell growth. Northern hybridization using specific cDNA probes for myotubularin and insulin I demonstrated that it also was induced by RITE. This is the first reported study to show that L1, myotubularin and insulin I are responsive to rapid hemispherical and not rapid linear stretch.