Time-dependent effects of perfluorinated compounds on viability in cerebellar granule neurons: Dependence on carbon chain length and functional group attached

The toxicity of long chained perfluoroalkyl acids (PFAAs) has previously been reported to be related to the length of the perfluorinated carbon chain and functional group attached. In the present study, we compared the cytotoxicity of six PFAAs, using primary cultures of rat cerebellar granule neurons (CGNs). Two perfluoroalkyl sulfonic acids (PFSAs, chain length C6 and C8) and four perfluoroalkyl carboxylic acids (PFCAs, chain length C8–C11) were studied. These PFAAs have been detected in human blood and the brain tissue of mammals. The cell viability trypan blue and MTT assays were used to determine toxicity potencies (based on LC50 values) after 24 h exposure (in descending order): perfluoroundecanoic acid (PFUnDA) ≥ perfluorodecanoic acid (PFDA) > perfluorooctanesulfonic acid potassium salt (PFOS) > perfluorononanoic acid (PFNA) > perfluorooctanoic acid (PFOA) > perfluorohexanesulfonic acid potassium salt (PFHxS). Concentrations of the six PFAAs that produced equipotent effects after 24 h exposure were used to further explore the dynamics of viability changes during this period. Therefore viability was assessed at 10, 30, 60, 90, 120 and 180 min as well as 6, 12, 18 and 24 h. A difference in the onset of reduction in viability was observed, occurring relatively quickly (30–60 min) for PFOS,...