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 its action remain elusive. The present study was aimed at analyzing the effects of NaAsO2 on primary cultures of rat astrocytes by determining DNA damage by comet assay, and by evaluating possible changes of the concentration of some 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 cell viability to 60% respect to untreated cells, high DNA damage was already observed after 24h treatment with 10 μM arsenite. Since arsenic is known to be not a direct-acting genotoxic agent, we investigated the possibility that its effects could depend on ROS formation. FACS analysis after CM-H2DCFDA staining evidenced an increase of ROS production at the lowest concentration (2.5 μM) of arsenite, while at higher doses (5 μM and 10 μM), ROS production decreased. An inverse correlation was found between ROS production and the expression of superoxide dismutases (SOD) 1 and 2. Finally, we found that PIPPin, an RNA-binding protein the concentration of which has been recently reported to change in response to stress induced by cadmium, undergoes a putative post-translational transition when cells are exposed to high doses of arsenicum.