Biochemical changes of hemoglobin and osmotic fragility of red blood cells in high fat diet rabbits. 
The aim of this study was to assess the effects of hyperlipidemia on auto-oxidation rate of hemoglobin (Hb; absorbance at 630 nm versus time), Hb derivatives and osmotic fragility of Red Blood Cells (RBCs).  These parameters were measured in twenty five 12-week-old male New Zealand white rabbits fed on a High Fat Diet (HFD) for a feeding period of 10 weeks.  We found that Hb concentration and RBC count were significantly decreased while white blood cell and platelet counts were significantly increased in HFD rabbits compared with control rabbits.  The Total Cholesterol (TC) was significantly increased (p < 0.01) in HFD rabbits compared with control rabbits with percentage normalized change of 1198% and Low Density Lipoprotein Cholesterol (LDLC) significantly increased (p < 0.01) in HFD rabbits compared with control rabbits with percentage normalized change of 1591%.  In HFD rabbits, oxyhemoglobin (HbO2) percentage was significantly decreased while met-hemoglobin (Met-Hb) percentage was significantly increased compared with control rabbits.  The auto-oxidation rate was significantly higher in HFD rabbits compared with controls.  Hyperlipidemia induced an increase in the osmotic fragility of RBCs and a decrease in their membrane elasticity compared with controls.  This study suggests that hyperlipidemia may produce reactive oxygen species and other free radicals which increase the auto-oxidation rate of Hb and promote the conversion of HbO2 and the fractions of unstable Hb molecules to Met-Hb and carboxyhemoglobin.  Increased platelet activation in hyperlipidemic rabbits may be of pathophysiological importance for the progression of atherosclerosis and thromboembolic complications.  The increase in osmotic fragility of RBCs may be attributed to the disturbance of ionic motion through the membrane and the change in molecular properties of the membrane macromolecules.