PROCOLLAGEN TYPE-I AND TYPE-III AND TRANSFORMING GROWTH-FACTOR-BETA GENE-EXPRESSION IN THE ARTERIAL-WALL AFTER EXPOSURE TO PERIARTERIAL BLOOD

THE STIFFENING AND thickening of the arterial wall after subarachnoid hemorrhage may reflect increased connective tissue. The purpose of thi s study was to examine the nature of collagen synthesis in response to periarterial blood. Rat femoral arteries were exposed to periarterial blood for varying lengths of time (control, 1, 3, 7, and 14 d). Dot-b lot analysis of total ribonucleic acid extracted from the arteries (n = 10 to 15 animals each) demonstrated that the expression of procollag en Types I and III messenger ribonucleic acid increased at 7 (threefol d) and 14 days. The expression of transforming growth factor-beta (TGF -beta), an important regulator of collagen synthesis, was markedly inc reased by 3 days (threefold), followed by a gradual decline. There wer e marked differences in procollagen Types I and III and TGF-beta gene expression between arteries exposed to blood and sham-operated arterie s for a period of 7 days (n = 25 animals). Northern blot analysis of t otal ribonucleic acid extracted from cultured vascular smooth muscle c ells showed that the treatment with a higher concentration of serum fo r 48 hours increased the expression of procollagen Types I and III and TGF-beta, whereas exposure to oxyhemoglobin did not. After exposure t o periarterial blood, arterial walls show increased synthesis of proco llagen Types I and III, perhaps a response to the increased secretion of TGF-beta, which in turn could be the result of exposure to serum fa ctors.