Effect of inorganic arsenic on rat cortical astrocytes in culture

Although inorganic arsenic is a well known poisonous metalloid, the cellular and molecular mechanisms of itsaction remain elusive. The present study was aimed at analyzing the effects of NaAsO2 on primary cultures of ratastrocytes by determining DNA damage by comet assay, and by evaluating possible changes of the concentration ofsome conserved heat shock proteins. Cells treated with inorganic arsenic underwent induction of Hsp70,demonstrating a state of stress. Moreover, although micromolar NaAsO2 treatments (60 μM) only reduced cellviability to 60% respect to untreated cells, high DNA damage was already observed after 24h treatment with 10 μMarsenite. Since arsenic is known to be not a direct-acting genotoxic agent, we investigated the possibility that itseffects could depend on ROS formation. FACS analysis after CM-H2DCFDA staining evidenced an increase ofROS production at the lowest concentration (2.5 μM) of arsenite, while at higher doses (5 μM and 10 μM), ROSproduction decreased. An inverse correlation was found between ROS production and the expression of superoxidedismutases (SOD) 1 and 2.Finally, we found that PIPPin, an RNA-binding protein the concentration of which has been recently reported tochange in response to stress induced by cadmium, undergoes a putative post-translational transition when cells areexposed to high doses of arsenicum.