QUANTIFICATION OF PRO-ALPHA-1(I) COLLAGEN MESSENGER-RNA IN SKIN BIOPSY SPECIMENS - LEVELS OF TRANSCRIPTION IN NORMAL SKIN AND IN GRANULOMA-ANNULARE

The synthesis of type I collagen, the major component of the skin, is known to be modulated in aging and in various skin diseases and treatm ents, In vivo analysis of type I collagen expression, however, is diff icult because of the low cell density of the dermis and the small amou nt of RNA obtainable from skin biopsy specimens, We present here a qua ntitative polymerase chain reaction method for the quantification of p ro alpha 1(I) collagen mRNA in skin punch biopsy specimens, The target ed mRNA and a synthetic RNA as an internal standard were co-amplified together with the same primers, Collagen synthesis was found to declin e after birth, so that the amount of proal(I) collagen mRNA in the ski n of 5- to 58-y-old donors was 17-37% of that in fetal skin, Slot-blot hybridization also indicated that the amount of pro alpha 1(I) collag en mRNA was much lower in adult skin than in fetal skin, In samples fr om lesional skin of two granuloma annulare patients, the number of pro alpha 1(I) mRNA molecules was increased 4- or 5-fold compared with va lues from nonlesional skin of the same patients, The method presented is a highly sensitive polymerase chain reaction application, requiring only very small amounts of total RNA.