[Effect of choroid plexus on sequestering cadmium and its pathomorphological change]

To investigate whether choroid plexus can sequester cadmium(Cd) and its pathomorphological change, rabbits were given the injections of 1.0, 2.0 and 4.0 mg CdCl2/kg through ear vein, respectively. 4 and 24 hours after Cd administration, animals were sacrificed, the samples of blood, cerebrospinal fluid (CSF), choroid plexus of lateral ventricle, cerebral cortex, liver and kidney were collected and the concentration of Cd in these tissues were measured. Samples of choroid plexus were rushed in saline thoroughly, then fixed. Pathomorphological changes of choroidal epithelial cells were observed in light microscopy and electron microscopy. The result showed that concentration of Cd in choroid plexus was higher than that in blood, CSF and cerebral cortex. In high-dose group, concentration of Cd in CSF was higher than that in other groups. Choroidal epithelial cells appeared vacuolation and granuler degeneration in light microscopy. Choroidal epithelial cells lost their normal slight to moderate convex luminal profiles, and appeared the loss of microvilli, shaped nuclei, increased cytoplasmic vacuolation, increased number of lysosomes, dilated rough endoplasmic reticulum, and widening of the gaps between adjacent cells. Choroid plexus could accumulate and sequester Cd to protect cerebral cortex from the fluxes of Cd in blood cadmium. When concentration of cd reached a certain level, sequestering action of choroid plexus was weak, or disappeared. Choroid plexus of lateral ventricle appeared pathomorphological change.