Ochratoxin A (OTA) is a ubiquitous fungal metabolite that contaminates animal feed and food. It is known for its nephrotoxicity, carcinogenicity, genotoxicity, and immunotoxicity. Considering the implication of OTA in public health, it is of great importance to find ways for reducing or even abolishing OTA induced toxic effect. Aspartame is a structural analogue of OTA and had been approved as a sweetener and flavor enhancer. The main target of the present work is to study the effect of OTA on the kidney ultrastructure and to evaluate the effect of aspartame on OTA induced nephrotoxicity. The Wister rats were divided into five equal groups (five in each): G1, without any treatment; G2, received sodium bicarbonate buffer solution (Both G1 & G2 served as control groups); G3, treated with aspartame alone; G4, treated with OTA alone; G5, treated with a combination of OTA and aspartame. OTA was given at a dose of 289 µg /kg body weight and aspartame was given at a dose of 25mg /kg body weight. Aspartame, OTA or a combination of OTA and aspartame was administered by gastric intubations every 48 hours for six weeks. The kidneys of all groups were studied using transmission electron microscope. The results showed that the glumeruli, proximal and distal convoluted tubules in G1, G2, G3 and G5 were normal. In G4, OTA induced ultrastructural changes of the glomeruli, proximal and distal convoluted tubules. The majority of the glomeruli of rats received OTA showed increase of the thickness of the basement membrane that appeared non homogenous with fusion of the secondary foot processes of the majority of the podocytes. Also, there was hypercellularity of the glomeruli and proliferation of the intraglomerular mesangial cells. Most of the cells of proximal convoluted tubules showed increased number of lysosomes and degeneration of some mitochondria with remnant cristae. The microvilli were lost and the lumen was compressed and filled with necrotic homogenous material. Most of the cells of distal convoluted tubules lost their basal infoldings of the cell membrane and showed degeneration of most of the mitochondria with remnant cristae. Some cells were binucleated. Aspartame prevented the ultrastructural changes induced by OTA. From this work it can be concluded that aspartame has a protective effect on OTA induced nephrotoxicity. |
