Treatments to prevent intimai hyperplasia, effective in balloon-injured rat arteries, have been disappointing when examined in a clinical setting. This may be related, in part, to differences in structure between rat and human vessels. Examination of the vessel at a single timepoint (usually two weeks after injury) may also provide incomplete or even misleading information regarding long-term effects. To compare the growth characteristics of experimental intimai lesions in arteries of approximately the same inner diameter in two species, rat aortae and rabbit carotid arteries were injured with a balloon catheter then the animals killed 2, 6, 12, 16 or 24 weeks later. Arteries were examined for changes in intima to media ratio, cell density, collagen synthesis and proliferation. At 2 weeks after injury vessels from both species had extensive neointimal formation with a high neointimal cell density and, compared to uninjured arteries, a decrease in medial cell density and an increase in collagen. In the rabbit artery the intima to media ratio increased with time after injury in a linear fashion, as did collagen synthesis. The ratio was significantly greater by 16 weeks than at 2 weeks with 75% fewer cells/mm 2. Proliferation at all times was very low. In the rat aorta cell density decreased linearly with time after injury so that the neointima at 12 weeks had 75% fewer cells/mm2 than at 2 weeks. Collagen synthesis and intima to media ratio did not change. Arterial changes in both models continued to at least 24 weeks. These differences in growth characteristics demonstrate that caution must be taken in extrapolating results from one animal model to another, even when the size of the vessels and the experimental procedures are comparable.
|Number of pages||8|
|Journal||Biomedical Research (India)|
|Publication status||Published - 1 Dec 2000|
- Animal models
- Collagen synthesis