SAF-1

Modulation of Cell Migration and Cell Tracking of the Gilthead Seabream (Sparus Aurata) SAF-1 Cells by Probiotics

Cell migration is essential for immunity and wound healing. Espinosa-Ruíz et al. optimized the in vitro scratch assay for the SAF-1 cell line from gilthead seabream fin. Cells were incubated with three species of extremophilic yeasts and a bacterium, then subjected to scratch and cell tracking assays. The objective was to evaluate the effects of probiotics on cell migration and identify the genetic mechanisms involved.

The viability of SAF-1 cells was assessed after 24 h incubation with inactivated probiotics (yeast D1, N6, CBS004, and bacterium SpPdp11). No significant differences (p > 0.05) were found in cell viability at different concentrations (5 × 10⁵, 5 × 10⁶, 5 × 10⁷ CFU/mL) compared to controls (Fig. 1A). A 24-h wound healing assay showed that frontal velocity of SAF-1 cells incubated with CBS004 and SpPdp11 significantly increased (3.63 ± 0.21 and 5.41 ± 0.24 μm/h, respectively) compared to controls. However, no significant differences were observed with D1 and N6 yeasts (Fig. 1C). A cell tracking assay was also performed on SAF-1 cells incubated with probiotics for 24 h (Fig. 2). Cells exposed to yeasts (D1, CBS004, or N6) showed no significant changes in velocity or directionality compared to controls. However, SAF-1 cells incubated with SpPdp11 had increased velocity and significantly higher cumulative and Euclidean distances than controls.

The Impact of PS-NPs on Intracellular ATP Content of Piscine Cell Lines

Nanoplastics contamination in marine and freshwater environments poses a global threat to aquatic life. Given the knowledge gap in polystyrene nanoplastics (PS-NPs) ecotoxicology, this study investigates the harmful effects of 20 nm and 80 nm PS-NPs on the rainbow trout (RTG-2) and gilthead seabream (SAF-1) cell lines. The aim is to understand the cytotoxicity and cellular responses of these cell lines to PS-NPs at different sizes and exposure times.

The cytotoxicity of 20 and 80 nm PS-NPs at increasing doses over 24 hours was evaluated at three time points (0.5, 6, and 24 hours) on RTG-2 and SAF-1 models by monitoring intracellular ATP content (Fig. 3, Fig. 4A-B). At 0.5 hours, 20 nm PS-NPs caused a significant ATP increase in RTG-2 up to 200 μg/mL, with 100 μg/mL resulting in an ATP content of 1.74 ± 0.12 relative to the negative control, while SAF-1 showed no significant changes. At 6 hours, the highest dose of 200 μg/mL caused opposite effects: ATP content in RTG-2 was 1.52 ± 0.12, while in SAF-1 it was 0.31 ± 0.06. At 24 hours, RTG-2 showed a general ATP increase, with a 1.62-fold change at 100 μg/mL, but SAF-1 ATP levels were unaffected up to 100 μg/mL, and 200 μg/mL resulted in the lowest median ATP content of 0.16 ± 0.07 (Fig. 3A). Thus, 200 μg/mL was identified as the lethal dose for SAF-1. To detect cytotoxic doses, RTG-2 were exposed to 400 and 800 μg/mL and evaluated at the same time points: 400 μg/mL caused a slight ATP increase only at 0.5 hours, while the highest dose led to a time-dependent decrease, with the lowest median ATP content of 0.01 ± 0.003 at 24 hours (Fig. 3B). The LC₅₀ at 24 hours was ~478.9 μg/mL for RTG-2 and ~119.0 μg/mL for SAF-1, with significant differences between the cell models. Positive controls (0.5% v/v NaN3) had relative ATP contents of 0.096-0.18 (RTG-2) and 0.013-0.06 (SAF-1).