Analysis of heavy metals in testis of cadmium-exposed rat using in air micro Particle Induced X-ray Emission(PIXE)

Abstract

Ashing and acid-digestion methods are necessary for analysis of microelements in biological sample. However, the analysis of two-dimensional distribution for the intracellular element was difficult. In-air micro-PIXE ( Particle Induced X-ray Emission) method is one of the few apparatus for measuring and visualizing the spatial distribution of elements in a single cell.
It is well known that cadmium (Cd) is toxic to various tissue, particularly the testis is highly sensitive to Cd toxicity. We have investigated the changes of micro element distribution in Cd-exposed testis.
1. Evaluation by in-air micro-PIXE method revealed that Cd and Fe distribution were increased in the interstitial tissues and seminiferous tubules. The histological findings indicated that the testicular tissue damage was advanced, which may have been caused by Fe flowing into seminiferous tubules followed by disintegration of the BTB. As a result, Fe was considered to enhance the tissue damage caused by Cd exposure.
2. We isolated Sertoli cells from rat testis and cultured them. Metallothionein(MT) levels, Heat shock protein 72(Hsp72) levels and Heme oxygenase-1(HO-1) levels were assayed in Sertoli cells, and these proteins were significantly increased by Cd exposure. Evaluation by in-air micro-PIXE method revealed that Cd and Fe distribution were increased in the Cd-exposed Sertoli cells, and Zn distribution was decreased.
These results suggested that Fe and Zn were closely associated with Heat shock proteins. And, HO-1 and MT is known as radical scavenger; therefore, these protein are suggested to protect Sertoli cells from Cd-toxicity.