Figure 7.

Neuronal activity and microglia response to brain injury following exposure to PFOA, a known immunotoxic congener. PFOA is an 8-carbon PFAS compound with a carboxylate head group. To observe the effects of PFOA on neuronal activity, we again used larvae of the Tg(elavl3:CaMPARI) background. (A) Representative heat map of neuronal activity of a 5-dpf control-treated larval brain. (B) Representative heat map of neuronal activity of a 5-dpf 64μM PFOA-treated larval brain. (C) Quantification of the regional and global (i.e., WB) neuronal activity as normalized FRed/FGreen ratios of 5-dpf control or 64μM PFOA-treated larvae. (D) Confocal micrograph of a 3-dpf control-treated larval brain with fluorescently labeled microglia. Image taken 4 hpi, with area of responding microglia shaded in magenta. (E) Confocal micrograph of a 3-dpf 64μM PFOA-treated larval brain with fluorescently labeled microglia. Image taken 4 hpi. (F) Quantification of the area of microglia response around the injury site at 4 hpi, as shown by the magenta overlays. n=8–9 fish per group. Error bars represent standard deviation. Box plot limits represent 25th to 75th percentile, with the midline representing the median. See Excel Table S1 for additional statistical details. Note: Ce, cerebellum; dpf, days postfertilization; FB, forebrain; HB, hindbrain; hpi, hours post-injury; ns, not significant; OT, optic tectum; PFAS, per- and polyfluoroalkyl substances; PFOA, perfluorooctanoic acid; WB, whole brain.