SURGICAL PREPARATION INDUCES INJURY AND PROMOTES SMOOTH-MUSCLE CELL-PROLIFERATION IN A CULTURE OF HUMAN SAPHENOUS-VEIN

Objective: The aim was to investigate the influence of vessel wall inj ury, incurred during routine vein preparation, on smooth muscle cell p roliferation. Methods: A newly developed quantitative organ culture wa s used, in which segments of human saphenous vein were cultured in med ium containing 30% fetal bovine serum and 1 muCi.ml-1 of [H-3]thymidin e for up to 14 d. Endothelial integrity was measured by scanning elect ron microscopy and medial cell viability by adenine nucleotide concent rations. Cell proliferation was measured by DNA concentration, global incorporation of [H-3]thymidine, and by counting labelled cells in aut oradiographs of transverse sections. Results: Surgical preparation led to endothelial injury and reduced adenine triphosphate concentration by 60%. Surgically prepared veins also suffered a significant decline in DNA concentration during culture, which implied that injury led to cell necrosis. Surgically prepared veins showed 2.1- and 2.7-fold grea ter global incorporation of [H-3]thymidine than freshly isolated veins after 7 and 14 d in culture, respectively, which corresponded with a 23-fold and 11-fold greater abundance of thymidine labelled cells in t he medial layer. Intimal thickening and the numbers of total and thymi dine labelled cells in the intimal layer were similar. Conclusions: Th e data show that injury incurred during routine surgical preparation i s associated with enhanced medial smooth muscle cell proliferation. Th e effect of injury was most probably to permit an increased response o f medial smooth muscle cells to serum derived mitogens.