Immunostimulation combined with liquid nitrogen freezing to construct a rat model of atherosclerotic vulnerable plaque

doi:10.3969/j.issn.2095-4344.2924

Abstract

Abstract:

BACKGROUND: Vulnerable plaque is the pathological basis of acute cardiac and cerebrovascular ischemic events. Establishing a suitable animal vulnerable plaque model is of great significance for guiding the prevention and treatment of cardiovascular and cerebrovascular diseases. However, there is no well-established method for constructing the vulnerable plaque model.

OBJECTIVE: To investigate whether immunostimulation can cooperate with liquid nitrogen freezing to establish an atherosclerotic vulnerable plaque model in rats, aiming to replicate the widely applicable atherosclerotic model.

METHODS: Forty male Sprague-Dawley rats were randomly divided into four groups after 1 week of adaptive feeding, namely, control group, high-fat group, liquid nitrogen group, immunostimulation + liquid nitrogen group. After 2 weeks of conventional diet and special high-fat diet, respectively, the rats in the control group and the other groups were given a single dose of vitamin D3 injection through the abdominal cavity. Rats in the control and high-fat diet groups were subjected to sham operation with no immunostimulation and liquid nitrogen freezing, and given routine diet and special high-fat diet for 10 weeks respectively. Rats in the liquid nitrogen group and immunostimulation + liquid nitrogen group were given liquid nitrogen freezing, followed by 10 weeks of high-fat diet. During this period, the rats in the immunostimulation + liquid nitrogen group were given subcutaneous injection of bovine serum albumin (3 times per week, for 3 weeks) and intraperitoneal injection of ovalbumin (3 days interval, 5 times in total). At 10 weeks after modeling, blood samples were taken to detect blood lipid index, inflammation and oxidative stress injury index, and heme oxygenase-1 (HO-1) protein expression in rats. The target blood vessel segments of each group were executed for hematoxylin-eosin staining, and the pathological changes of atherosclerotic plaques were observed under light microscopy. The study protocol was approved by the Animal Ethics Committee of Southwest Medical University, with an approval No. IACUC:20170917006.

RESULTS AND CONCLUSION: Compared with the control group, there were no significant changes in cholesterol level, inflammatory and oxidative stress index, HO-1 protein expression and histopathological examination in the high-fat group (P > 0.05). Compared with the control and high-fat groups, the levels of serum lipids, inflammatory and oxidative stress indicators and HO-1 protein expression in the liquid nitrogen and immunostimulation + liquid nitrogen groups were significantly increased (P < 0.05). Histopathological examination also indicated that there were obvious plaques, and the increasing trend in the immunostimulation + liquid nitrogen group was more significant (P < 0.05). Compared with the liquid nitrogen group, the levels of serum lipids, inflammatory and oxidative stress indexes and HO-1 protein expression in the immunostimulation + liquid nitrogen group were significantly increased (P < 0.05), and histopathological examination also showed more obvious atherosclerotic plaques. Therefore, immunostimulation could accelerate the formation of rat common carotid atherosclerotic vulnerable plaque model in cooperation with liquid nitrogen freezing injury, which lays a foundation for the intervention experiment of atherosclerotic disease.

Key words: experiment, model, rat, immune, freezing, atherosclerosis, vascular construction, common carotid artery

CLC Number:

Wei Gang, Gao Shangyuan, Zhang Ying, Huang Weiyi. Immunostimulation combined with liquid nitrogen freezing to construct a rat model of atherosclerotic vulnerable plaque[J]. Chinese Journal of Tissue Engineering Research, 2020, 24(35): 5656-5661.

Figures/Tables 5

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