A MORPHOLOGICAL AND MICROANALYTICAL INVESTIGATION INTO THE UPTAKE OF PARTICULATE IRON ACROSS THE GASTROINTESTINAL-TRACT OF RATS

The uptake and translocation of particulate iron across the gastrointe stinal (GI) mucosa of young adult rats has been investigated using a r ange of morphological techniques and X-ray microanalysis (XRMA). In an imals fed a suspension of iron powder constituted of metallic iron par ticles ranging in size from 6-3 mu m down to 5-30 nm, light microscopi c histochemistry has clearly revealed iron deposits within the tissues of the duodenum. Scanning electron microscopy of the duodenal tissue by back-scattered electron imaging has complemented the light microsco pic observations and revealed a selective localization of iron in the villi with variation in levels of iron uptake by the mucosal cells. Ul trastructural and XRMA analysis of duodenum has established the presen ce of metallic iron nanoparticles within the brush border, lateral int ercellular spaces of the mucosal cells, mitochondrial cristae and cyto plasm of both mucosal and stromal cells. The observations indicate tha t metallic iron particles, in the nano-size range, may be taken up by the GI mucosa and that the passage of such particles across the epithe lial barrier may take place through both a paracellular as well as a t ranscytotic process.