Histological study of the effect of Aluminum on the brain, liver and kidney of adult male rats

ABSTRACT

Sixteen adult male albino rats were utilized in this work aiming to study the effect of chronic oral low dose of aluminum on the histological structure of the brain frontal cortex, liver and kidney and its interference with iron content of these tissues. The animals were classified into two equal groups [8 animals each], a control and an experimental one. They were housed in stainless steel wire cages and provided with distilled water in stainless steel trays. The animals of the experimental group received daily 20 mg/kg body weight of aluminum chloride dissolved in their drinking water for successive 4 months. At the time of sacrifice, all the animals were anaesthetized with ether inhalation and their brain cerebral hemispheres, livers and kidneys were dissected out carefully, treated with several stains and processed for light microscope examination. Examination of the frontal cortexes of aluminum treated animals showed the appearance of small, irregular and darkly stained cells in the superficial layers. The neuropil of all cortical layers showed numerous glial cells. Furthermore, astrocytes of this neuropil showed an observable depletion of the glial fibrillary acidic protein with thinning and disruption of their processes surrounding the blood vessels. On the other hand, liver sections of the same group revealed shrinkage of some hepatocytes and widening of the adjacent sinusoidal spaces. The portal areas showed congested blood vessels with mononuclear and multinuclear cellular infiltrations. Increased collagen deposition was detected around the central veins. Sections of the renal cortex of the same animals showed dilated convoluted tubules with absence of the luminal brush border of the proximal ones. Areas of cortical interstitial cellular infiltration and fibrosis were detected. Porl's stained sections of the frontal cortex of the treated animals showed the presence of scattered iron granules in the neuropil and around some blood capillaries. Liver sections of the same animals showed coarse iron granules in the hepatocytes, in the wall of the large branches of the portal vein and in the adjacent blood sinusoids. Also, scattered iron granules were noticed in the wall of some renal tubules and glomeruli. It can be concluded that despite the suggested low gastrointestinal absorption of aluminum, the results of this work revealed that chronic low dose of oral aluminum had cytotoxic effects on the frontal cortex, liver and kidney. Furthermore, the selective deposition of free iron granules in certain areas of these examined tissues may have the potentiality for induction of the observed alterations. Moreover, the observable depletion of the glial fibrillary acidic protein in the astrocytes of the frontal cortex may reflect an impairment of the astrocyte functions and the subsequent neuronal degeneration. So, it is advisable to avoid usage of aluminum utensils in food processing