Histological and histochemical study on the protective role of selenium aginst the potential hazards of the food colouring additive, orange II inthe kidney of mice

ABSTRACT

The study was conducted to demonstrate the potential hazards of the food colouring additives in the kidney of mice by identifying the adverse effects of one of these additives, orange II, and the way selenium, an antioxidant, could protect the kidney tissues and prevents the occurrence of such undesirable effects. Fifty adult animals were divided into four groups. The control [10 animals] had received one ml. saline injections. The second group [10 animals] has received sodium selenite alone, [0.03 microgram / dose], dissolved in one ml. saline. Thirty subcutaneous injections were given in 60 days [one injection every other day]. The third group [20 animals], 15 of which had received the colouring additive, orange II alone, [18 mg /dose] dissolved in water and given through gastric tube. Also, thirty doses were given in 60 days [one dose every other day]. Five more animals of this group had received only water [control for this group]. The fourth group [10 animals] had received both sodium selenite and orange II in same doses and same administration routes. All animals were sacrificed after 60 days except five animals of the third group [those received orange II alone], which were retained for 15 more days to recover [nothing administered during this period], then sacrificed. The kidneys of all animals were dissected out and specimens were fixed in buffered formalin, processed and paraffin sectioned and stained with Hematoxylin and Eosin, Mallory and PAS stains. Other specimens were cryostate sectioned and the histochemistry of acid and alkaline phosphatases and succinic dehydrogenase were studied. The results obtained had demonstrated beside the normal histology and histochemistry of the studied control specimens, the changes that resulted from selenium and the colouring additive. Specifically, selenium alone being administered in therapeutic doses has mild effect restricted to mild vascular congestion with no actual damage. The colouring additive alone was the subject of variable adverse effects. Massive vascular congestion, interstitial haemorrhage and degenerative changes in the form of cytoplasmic vacuolations, tubular and interstitial necrosis as well as heavy round cellular infiltrations were detected. These findings have been reflected upon the histological and histochemical outcome. Thus, there have been an increase of the connective tissue elements, a decrease of PAS reactive materials and reduction of alkaline phosphatase and succinic dehydrogenase enzymatic activities. Acid phosphatase reactivity appeared strong in certain areas apparently where tissue necrosis and macrophage cells infiltration were active but a reduction of the enzyme activity was obvious when these tissue changes no longer exist. The recovery period did not alter the results to an appreciable degree, but amelioration of the adverse changes could be observed. The animal group that received selenium and the colouring agent combined, has demonstrated almost normal findings, no drastic changes have been observed. This would indicate a protective role of selenium on tissues subjected to the hazards of the colouring agent