Study on mechanism of c-Myc in restenosis after coronary artery bypass grafting.

OBJECTIVE To study the actions of c-Myc gene fragments in restenosis after coronary artery bypass grafting (CABG). MATERIALS AND METHODS A total of 25 healthy pure breeds New Zealand white rabbits were randomly divided into 5 groups according to weight, 5 in each group. The external jugular vein is placed at ipsilateral common carotid artery and sampling at 6h, 2d, 7d, 14d and 28d. The expression of the c-Myc positive cell population was observed in different time using immunohistochemistry and morphological analysis. The thickness and ratio of luminal intima and media were measured by the computer image analytical method. RESULTS The luminal intima and media thickness at day 7 is significantly thickening (p <0.01) from 6h while it has not changed (p >0.05) at day 14 and 28 compared to day 7. C-Myc proteins are gradually increased from 6h to day 7, reached a peak (p <0.01) at day 7; started declining from day 14-28. The difference has statistical significance (p <0.01) compared to day 7. CONCLUSIONS C-Myc positive cell population has reached a peak after transplantation, which is identical with the peak of fast intimal proliferation. It indicates that c-Myc protein expression is closely associated to intimal proliferation. It can act as an indicator for intimal proliferation after vascular injuries in the early stage of reactions.