Fig. 3: Maternal SARS-CoV-2 vaccination induces hippocampal cell proliferation and neuronal differentiation in pups at 1 month postnatally.

a Representative confocal micrographs of the newborn cells, labeled by proliferative marker (BrdU) in the dentate gyrus (DG) of pups from SARS-CoV-2-vaccinated pregnant mice with the inoculated doses of 50 (SCV-50) μL and 100 (SCV-100) μL and the vehicle controls. Two higher magnification (63 × oil immersion Lens) images of the inset boxes in a were shown on the right (white). The image above was related to a granular layer, and the image below was related to a hilus. (b, c) Representative confocal images of the DG in each group showing BrdU (red) and DCX (green) (b), BrdU (red) and NeuN (green) (c). The inset boxes in b and c were magnified (63 × oil immersion Lens), as reflected by the higher power images in the right (BrdU: white, NeuN and DCX: green). d The number of BrdU⁺ cells were analyzed in the unilateral DG of pups 24 h after the first BrdU injection. n = 10 pups (Control group), n = 8 (SCV-50 μL group), and n = 9 (SCV-100 μL group). Quantification of the numbers of BrdU⁺/DCX⁺ (e) and BrdU⁺/NeuN⁺ cells (f) in the DG. For e: n = 7 pups (Control group), n = 8 (SCV-50 μL and SCV-100 μL groups). For f: n = 5 pups (Control group), n = 6 (SCV-50 μL and SCV-100 μL groups). g Percentage of BrdU⁺/DCX⁺, BrdU⁺/IBA1⁺ and BrdU⁺/GFAP⁺ cells to total BrdU⁺ in the DG among the three groups. Statistics calculated by one-way ANOVA followed by Tukey HSD test. ns: non-significant; *p < 0.05, **p < 0.01, ***p < 0.001. Graphs indicate mean ± s.e.m. Scale bar: 200 μm in a, b and c, 20 μm in higher power images.