Korean Circ J.  2007 Feb;37(2):78-83. 10.4070/kcj.2007.37.2.78.

A Slight Variation in the Age of Rats Commonly used as a Carotid Artery Injury Model Results in a Large Difference in Neointima Formation

• Kwon JS
• Park NK
• Jeong IH
• Kim YK
• Bae JH
• Hwang KK
• Kim DW
• Cho MC

• KMID: 1859085
• DOI: http://doi.org/10.4070/kcj.2007.37.2.78

Abstract

BACKGROUND AND OBJECTIVES: The degree of neointima formation after infliction of a carotid artery balloon injury in rats varies greatly depending on the sex, age, species and operational method. Strong variation is common, even within only a single control. This study attempted to find if there was any significant difference in neointima formation following a carotid artery balloon injury in 6 to 12 week old rats; the age commonly used in these types of experiments.
MATERIALS AND METHODS
A balloon injury was inflicted on the carotid arteries of male SpragueDawley rats at 6 (n=9, 250-270 g), 8 (n=8, 280-300 g) and 11 weeks (n=10, 320-340 g) of age. Two weeks postoperation, a histomorphometric analysis was carried out. The vascular smooth muscle cell proliferation was measured in situ via BrdU incorporation 2 days after injury infliction.
RESULTS
The neointima areas of the 6 week (0.22+/-0.04 mm2) and 8 week old groups (0.17+/-0.08 mm2) were 3.1 and 2.4 times larger than that of the 11 week old group (0.07+/-0.03 mm2). The mitotic index was significantly reduced in 11 week old group (n=4, 9.22+/-1.51%) compared to those of the 6 (n=4, 25.03+/-3.92%) and 8 week old (n=4, 21.66+/-3.66%) groups.
CONCLUSION
Special care should be taken when interpreting neointima formation, as even a slight variation in the age and weight in 6 to 12 week old (250-340 g) rats; the age commonly used in these types of experiments, results in an unexpectedly large difference.

Keyword

Neointimal formation; Carotid artery injuries; Aging

MeSH Terms

Aging
Animals
Bromodeoxyuridine
Carotid Arteries*
Carotid Artery Injuries*
Cell Proliferation
Humans
Male
Mitotic Index
Muscle, Smooth, Vascular
Neointima*
Rats*
Bromodeoxyuridine