Comparison of the intracellular behavior of gold (Au) and indium (In) in testicle after their parenteral administration.

The subcellular behavior of several mineral elements was studied using modern techniques of observation like transmission electron microscopy and analysis like electron probe microanalysis and secondary ion mass spectrometry. In the present ultrastructural and analytical investigations, we undertake to compare the intracellular behavior of a heavy metal, gold, and a III-A group element, indium, on rat testicular tissues after their parenteral administrations. Our ultrastructural results showed that while gold was found only in the lysosomes of Leydig cells under electron dense needles, indium was observed as electron-dense deposits in the lysosomes of both Leydig and Sertoli cells. No ultrastructural modifications were observed in the testicular tissues of the control rats. The microanalytical study showed that gold was concentrated in lysosomes with sulfur as a sulfate crystalline structure whereas indium was concentrated in the same organelle as insoluble phosphate salt. These results demonstrated that testicular Leydig and Sertoli cells have the ability to selectively concentrate indium but gold was concentrated only in the first kind of cells. The mechanism implicated in this concentration phenomenon is a biochemical one involving intralysosomal hydrolytic enzymes, the acid phosphatase and the arylsulfatase. This mechanism occurs in order to protect the organism and to avoid the presence of toxic metals under soluble and free form.

Role of parietal and principal gastric mucosa cells in the phenomenon of concentration of aluminum and indium.

The subcellular behavior of aluminum and indium, used in medical and industrial fields, was studied in the gastric mucosa and the liver after their intragastric administration to rats, using, two of the most sensitive methods of observation and microanalysis, the transmission electron microscopy, and the secondary ion mass spectrometry. The ultrastructural study showed the presence of electron dense deposits, in the lysosomes of parietal and principal gastric mucosa cells but no loaded lysosomes were observed in the different studied hepatic territories. The microanalytical study allowed the identification of the chemical species present in those deposits as aluminum or indium isotopes and the cartography of their distribution. No modification was observed in control rats tissues. In comparison to previous studies describing the mechanism of aluminum concentration in the gastric mucosa and showing that this element was concentrated in the lysosomes of fundic and antral human gastric mucosa, our study provided additional informations about the types of cells involved in the phenomenon of concentration of aluminum and indium, which are the parietal and the principal cells of the gastric mucosa. Our study demonstrated that these cells have the ability to concentrate selectively aluminum and indium in their lysosomes, as a defensive reaction against intoxication by foreign elements.

Microscopy and microanalysis study of the indium (In) behavior in the intestinal mucosa, the liver, the kidney and the testicle.

Several studies have demonstrated that In used in medicine has several impacts on organs like spleen and lungs after its systemic administration. In the present study, ultrastructural and microanalytical methods were used to investigate the impact of the presence of this element in the intestinal mucosa, the liver, the kidney and the testicle after its administration in two ways. After intraperitoneal administration, In was selectively concentrated in the lysosomes of hepatocytes, of tubular proximal convoluted cells and of Sertoli and Leydig cells. After intragastric administration, ultrastructural study showed that this element was concentrated in the lysosomes of duodenal enterocytes. Microanalytical methods showed that In was precipitated in those organelles in the form of insoluble phosphate salts. Similarly to other studies, it seemed that since In is a foreign element for the organism, it was precipitated in lysosomes, very probably due to the activity of an intralysosomal enzyme the acid phosphatase, to avoid its invasion to organism via the blood. This mechanism of precipitation of the mineral elements is of great interest in the process of defensive reaction of the organism against intoxication by foreign elements.

[Role of the duodenal and hepatic cells lysosomes in the phenomenon of gadolinium accumulation]. / Rôle des lysosomes des cellules duodénales et hépatiques dans le phénomène d'accumulation du gadolinium.

The behaviour of the intestinal mucosa and of the liver after an administration of a gadolinium salt has been studied in the Wistar rat using transmission electron microscopy, ion mass spectrometry, and electron probe microanalysis. Six hours after parenteral administration, gadolinium is concentrated with phosphorus in the lysosomes of hepatocytes and Küppfer cells. Six hours after its oral administration, gadolinium is detected in the duodenal enterocytes lysosomes, but never in those of the liver cells. It is suggested that this mechanism of local concentration limits the diffusion through the digestive barrier of foreign elements, some of them being toxic and none of them having a physiological function.