Change of the blood cholesterol and lipoproteins concentration in female rabbits maintained at low temperature

Abstract

In the adaptive process to low temperature the lipidic metabolism is involved in energy production specially by stimulating lipolysis in the adipose tissue (AT) however, little is known about the participation of circulating cholesterol, low (LDL) and high density (HDL). This study was aimed to determine the effect of the prolonged exposure to low temperature on blood concentration of the above components and their possible contribution to the energetic metabolism in female rabbits.

Twelve adult female NZW rabbits weighing 1.74 ± 0.18 Kg kept in separated cages under 12h light cycles and daily fed with 100g of commercial pellets were used. The control group was maintained at room temperature (27 ± 2°C) and the experimental group at 5°C ± 1°C in a cold room. On days 0, 30 and 60 blood samples were obtained by heart punction. Plasma was used for the determination of total cholesterol, HDL-chol and LDL-chol using enzymatic methods. Results were expressed in mg/dl and statistic analysis was performed using Student "t" test and p < 0.05 was considered statistically significant.

The results showed a decrease of plasma cholesterol, LDL and HDL at 30 days of exposure to low temperature. At 60 days, the hypocholesterolemia was maintained, as well as the decrease of the LDL, but the HDL recovered the level observed at 27°C. It is possible that the plasma LDL and HDL constitute a significant energy source for the homeothermic organism exposed to low temperature.