Cholesterol (from plant)

(1) Rats were housed in a room maintained at a 12-h light-dark cycle and a constant temperature of 22±2 °C
(2) Wistar rats were always chosen for hyperlipidemia studies since this species shows a moderate increase in serum cholesterol and triglyceride level due to a high-cholesterol diet and no substantial atherosclerosis develops; therefore, the direct myocardial effect of hyperlipidemia, independent from atherosclerosis, can be studied in this model.

(1) The cholesterol-fed rabbit is a widely used model for experimental atherosclerosis research as cholesterol only cause atherosclerotic changes in the rabbit arterial intima, which was very similar to human atherosclerosis.
(2) As the absorption of dietary cholesterol requires fat, you must add oil into the diet. Otherwise, rabbits will use their internal fat, which makes them lean or sick. In addition, using soybean oil, which consists of unsaturated fatty acids, can prevent the levels of plasma cholesterol from becoming too high. Other vegetable oils, such as peanut oil or corn oil, can be used because they are all unsaturated fatty acids. Animal fat (saturated fatty acids) like tallow and lard is not recommended.
(3) 0.3-0.5% cholesterol diet is recommended for most experiments. Rabbits cannot tolerate a 1-2% cholesterol diet for a month as they develop severe liver dysfunction.
(4) Adult rabbits at 4 months or older can consume approximately ~150 g a day. You can either feed ab libitum or restricted (100-150 g/day/adult rabbit).
(5) Plasma lipids should be measured weekly, especially for the first 4 weeks, because you need to determine whether plasma levels of cholesterol are elevated in each animal. Non-responder rabbits can be excluded from the experiments if their plasma cholesterol levels do not increase after cholesterol diet feeding.
(6) Plasma lipoproteins can be measured at 8 and 16 weeks when the plasma levels of cholesterol are stable.
(7) The age of rabbits should be considered because young rabbits are more susceptible to aortic atherosclerosis than old rabbits even though they have similar plasma cholesterol levels. 4-6-month-old rabbits are usually used for cholesterol feeding experiments.
(8) Male and female rabbits are different in terms of response to a cholesterol diet and atherosclerosis. In our experience, female rabbits develop higher hypercholesterolemia and greater aortic lesions than their counterpart male rabbits. In general, male rabbits are recommended for experiments because estrogen may influence the results.