Toxicological effects and ultrastructural changes induced by lanthanum and cerium in ovary and uterus of Wistar rats.

Rare earths have been widely used in a huge number of areas in industry and medicine. Therefore, they exist in the environment and possibly accumulated within the human body. However their effects in the living organism particularly in the female reproductive system are still unclear. In this work, the subcellular behavior of lanthanum and cerium was investigated through the Transmission Electron Microscopy (TEM), in different territories of the reproductive system of Wistar rats exposed intraperitoneally to soluble solution of these elements during 2 weeks. Ultrastructural investigations of ultrathin sections from uterus and ovary of treated rats revealed the existence of inclusions with high electron density and heterogeneous aspects in the lysosomes of uterus and ovary cells. Many disruptions of architecture were observed, accompanied with several changes like vacuolations, significant expansion of the endoplasmic reticulum, mitochondrial alterations and necrotic cells, demonstrating the toxicity of these elements with doses used. Phagolysosomes as well as eosinophils were also seen. Our experimental investigations revealed no intralysosomal inclusions in ultrathin sections of the uterus and ovary of pregnant control females. The original mechanism implicated in this insolubilization-concentration phenomenon of these elements, as non-soluble phosphate form, in the lysosomes is a biochemical one involving intralysosomal hydrolytic enzymes, the acid phosphatase.