Lipid fluidity of triacylglycerol-rich lipoproteins isolated from copper-deficient rats

Triacylglycerol-rich lipoproteins (TGRLP) were isolated from Cu-deficient and control rats, TGRLP from Cu-deficient rats appeared more fluid than those from controls as sensed by the fluorescence anisotropy of 1,6-diphenyl-1-3,5-hexatriene (DPH), This high fluidity was related to a low cholesterol: phospholipid ratio and high triacylglycerol content in these lipoproteins. TGRLP from Cu-deficient rats were more susceptible to in vitro peroxidation than lipoproteins from control rats as shown by the rate of diene conjugation. The damage induced by the peroxidation resulted in a more ordered state of the lipid fraction especially in Lipoproteins from Cu-deficient rats, Thus, after in vitro peroxidation, TGRLP from Cu-deficient rats were more rigid than those from controls, These results suggest that Cu deficiency induces modifications in physicochemical properties of TGRLP which could affect their metabolism.