[Chronic stress model in New Zealand white rabbit with hyperlipidemia]

Objective: To establish and evaluate chronic stress model in New Zealand white rabbit with hyperlipidemia. Methods: A total of 45 clearing grade male New Zealand white rabbits were divided into four groups with random number table method: control (CON), normal diet combined with chronic stress for 8 weeks (CON+ CS), high fat diet (HFD) and high fat diet for 4 weeks combined with chronic stress for 8 weeks (HFD+ CS). Both social stress and physical stress methods were adopted.One-way ANOVA was used for comparison among groups. Results: (1) Chronic stress model assessments: ①body weight, the weight gain of stress groups was significantly reduced; ②behavioral assessment, rabbits exposed to stress in CON+ CS and HFD+ CS group [54%±7%, 55%±5%] exhibited more inactivity behavior than CON and HFD group [27%±5.28%, 34%±6%, P<0.01, P<0.05]; ③serum indexes: after stress regime for 4 weeks, cortisol of HFD+ CS was higher than HFD group [(60±5) ng/ml vs (38±4) ng/ml, P=0.001]. After 8 weeks, the serum levels of hs-CRP and IL-6 also elevated. (2) The effect of hyperlipidemia on chronic stress: compared with CON+ CS, HFD+ CS group showed more inactivity behavior and rising levels of cortisol, hs-CRP and IL-6. (3) Blood lipids: chronic stress induced raised serum total cholesterol. Conclusions: (1)Chronic stress model in rabbit with hyperlipidemia could be successfully established with 4-week high lipid feed followed by social stress combined with physical stress for 8 weeks.(2) Hyperlipidemia and chronic stress influences each other.