Comparison of Apolipoprotein E Knockout Mice and Spontaneously Hyperlipidemic Mice in Porphyromonas gingivalis-Induced Atherosclerosis

Abstract

Porphyromonas gingivalis was shown to accelerate atheroma formation in murine models such as apolipoprotein E knockout (ApoE-KO) mice and BALB/c. apoE-deficient spontaneously hyperlipidemic (C. KOR-Apoeshl) mice. The purpose of this study is to characterize mouse gender and strain differences in P. gingivalis-induced atherosclerosis. Male and female ApoE-KO mice (10 weeks old) and age- and sex-matched C. KOR-Apoeshl mice were intravenously injected with P. gingivalis three times a week for 3 weeks. Mice were then killed at 14 weeks. Atherosclerotic plaques in the proximal aorta were determined by Oil Red O staining. Serum lipid parameters (total cholesterol, TC; high density lipoprotein, HDL; and low density lipoprotein, LDL) and body weights were evaluated. P. gingivalis injection significantly enhanced the formation of atherosclerotic plaque in both ApoE-KO and Apoeshl mice. Moreover, atherosclerotic lesion area was slightly larger in ApoE-KO mice than in Apoeshl mice, while both model mice displayed similar body weight gain regardless of bacterial infection. The weight gain of male was larger than that of female in the period, and the TC of Apoeshl mice was higher than that of ApoE-KO mice. Furthermore, P. gingivalis injection had elevated serum TC and LDL levels compared to the non-injected Apoeshl mice group. These results suggest that P. gingivalis induces atherosclerosis in both ApoE-KO and Apoeshl mice subsequently increasingTC and LDL levels. Thus, the Apoeshl mice may serve as a substitute for ApoEKO mice at the point of it being more natural and superior in examination of temporal change of morbidity, if we take account the import cost and the complication of maintenance of genetically modified mice.