Session Speaker

The Effects of a High Fat Diet on Trace Elements in Several Tissues of Rabbit using Atomic Absorption Spectroscopy
Mohamed Anwar K Abdelhalim, Hisham A Alhadlaq and Sherif Abdelmottaleb Moussa
Saudi Arabia

Atherosclerosis is a disease of large- and medium-sized arteries, and is characterized by endothelial dysfunction (malfunction of the cells lining the inside of the artery wall), vascular inflammation, migration of smooth muscle cells to the inner lining of the artery (intima) and the build-up of lipids, cholesterol and cellular debris within the intima of the vessel wall. Oxidation of LDL has been found to increase its uptake in macrophages and lead to formation of macrophage foam cells. These activated macrophages produce numerous factors that are injurious to the endothelium, leading to plaque formation. The mechanism of atherogenesis is not yet fully understood despite intense study in this area. The effects of high fat diet (HFD) on the changes of trace elements [iron (Fe), copper (Cu) and zinc (Zn)] in several tissues of rabbits have not been documented before. Thus, the aim of this study was to elucidate the changes in trace elements in several tissues of rabbits fed on HFD for a period of feeding of 10 weeks.

Results: The HFD group was fed a normal rabbit chow supplemented with 1.0% cholesterol plus 1.0% olive oil. Fe, Cu and Zn concentrations were measured in four types of tissue from control and HFD rabbits using atomic absorption spectroscopy. Comparing HFD rabbits to control rabbits, we found that the highest percentage change of increase of Fe was 95% in lung tissue, while the lowest percentage change of increase of Fe was 7% in kidney tissue; the highest percentage change of decrease of Cu was 16% in aortic tissue, while the lowest percentage change of decrease of Cu was 6% in kidney tissue; and the highest percentage change of decrease of Zn was 71% in kidney tissue, while the lowest percentage change of decrease of Zn was 8% in lung tissue.

Conclusions: We used AAS to elucidate the role of a HFD on trace elements (Fe, Cu and Zn) in different tissues of HFD rabbits. These results suggest that Fe plays a major role in atherogenesis; it may accelerate the process of atherosclerosis probably through the production of free radicals, deposition and absorption of intracellular and extracellular lipids in the intima, connective tissue formation, smooth muscle proliferation, lower matrix degradation capacity and increased plaque stability. Furthermore, inducing anemia in HFD rabbits may delay or inhibit the progression of atherosclerosis. Cu plays a minor role in atherogenesis and Cu supplements may inhibit the progression of atherogenesis, perhaps by reducing the migration of smooth muscle cells from the media to the intima. Zn plays a major role in atherogenesis and that it may act as an endogenous protective factor against atherosclerosis perhaps by reducing lesion Fe content, intracellular and extracellular lipids in the intima, connective tissue formation, and smooth muscle proliferation. These results suggest that it may be possible to use the measurement of changes in trace elements in different tissues of rabbits as an important risk factor during the progression of atherosclerosis.

References:

[1] Abdelhalim, MAK, Sato M, Ohshima N: Effects of cholesterol feeding periods on aortic mechanical properties of rabbits.JSME International Journal 1994, 37: 79-86.

[2] Stocker R, keaney JF Jr: Role of oxidative modifications in atherosclerosis. Physiol Rev 2004, 84 (4): 1381-1478.

[3] Abdelhalim, MAK, Alhadlaq HA: Effects of cholesterol feeding periods on blood haematology and biochemistry of rabbits. International Journal of Biological Chemistry 2008, 2 (2): 49-53.