*2.2. Astaxanthin Reversed the Morphological Changes in LPS-Activated DCs*

Mature DCs were easily aggregated to form larger clusters and longer extensions [33]. Upon LPS stimulation alone, the size of clusters and the extension morphologies of DCs were increased, compared with the untreated and the astaxanthin-alone group. However, these processes were impaired by astaxanthin (Figure 3A,C). Meanwhile, the size of clusters and the cell shape index (major axis/minor axis) of each group were measured. As shown in Figure 3B,D, these two indexes were markedly increased after LPS stimulation. Treatment of astaxanthin significantly suppressed the increase of two indexes in LPS-induced DCs. These results indicated that astaxanthin attenuated the morphological changes of LPSactivated DCs.

**Figure 3.** Astaxanthin decreased the morphological changes of LPS-stimulated DCs. After stimulation for 24 h with astaxanthin or plus 100 ng/mL LPS, DC aggregation (**A**) and dendrites (**C**) were observed by microscopy. (**B**,**D**) Statistical results on the size of DC cluster formation and the cellular shape indices in each group. Data shown are the means ± s.d. of 40 clusters or DCs randomly selected from 3 separate experiments. Statistical significance is assessed by one-way ANOVA analysis to compare the results between different groups. \*\* *p* < 0.01. Bars: (**A**) 100 μm; (**C**) 20 μm.
