Figure 2.

Prenatal exposure to MeHg increases neuronal differentiation of cortical precursors at the expense of their proliferation in vivo

(A) Schematic of prenatal exposure to MeHg in pregnant mice, created with BioRender.com. 0ppm (control) and 0.2ppm MeHg were administered through drinking water to pregnant mice starting at E0 until E15. At E15 brains were collected for immunohistochemistry.

(B, E) Images of E15 cerebral cortex sections from embryos receiving 0 and 0.2ppm MeHg treatment, immunostained for Pax6 (B, green), Ki67 (B, red) or Tbr2 (E, red) and counterstained for Hoechst (blue). Scale bar: 25 μm.

(C, D, and F) Quantitative analysis of the number and proportion of Ki67⁺/Pax6⁺ proliferating cortical precursors (C and D) and Tbr2+ intermediate progenitors (F) within VZ and SVZ/IZ, determined from sections similar to those shown in (B, E). n = 3 embryos/group, Student’s t test ∗p < 0.05.

(G) Images of E15 cerebral cortex sections from embryos receiving 0 and 0.2ppm MeHg treatment, immunostained for DCX (G, green) and counterstained for Hoechst (blue). Scale bar: 25 μm.

(H) Quantitative analysis of the number of DCX⁺ immature neurons within VZ, determined from sections similar to those shown in (G). n = 4 embryos/group, Student’s t test, ∗p < 0.05.

(I) Quantitative analysis of thickness for the CP was determined from coronal sections similar to those shown in (G). n = 3 embryos/group, Student’s t test, ∗∗p < 0.01.

(J) Images of E15 cerebral cortex sections from embryos receiving 0 and 0.2ppm MeHg treatment, immunostained for Tbr1 (red) and counterstained for Hoechst (blue). Scale bar: 25 μm.

(K) Quantitative analysis of the number of Tbr1⁺ deep layer mature neurons within CP, determined from sections similar to those shown in (J). n = 4 embryos/group. Error bars indicate the standard error of the mean (SEM). See also Figure S2.