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Fig. 1.
Reactive oxygen species (ROS) specifically affect
collagen synthesis in neonatal rat cardiac fibroblasts. Neonatal
(A) and adult (B) cardiac fibroblasts were
treated for 24 h with DMEM alone, H2O2
(0.05-5 µM), or xanthine plus xanthine oxide (XXO; 500 µM + 0.001-0.1 mU/ml). Fibroblasts were treated in the presence of
[3H]leucine (total protein synthesis) or
[3H]proline (last 4 h; collagen synthesis), and
[3H]leucine incorporation and collagenase-sensitive
[3H]proline incorporation were determined. Data for
[3H]leucine are calculated as dpm/1,000 cells. Data for
collagenase-sensitive [3H]proline incorporation are
calculated as the percent of total protein synthesis. Means ± SE
from 6-12 experiments. Significance was determined by Student's
t-test; *P 
0.05.
