Fig. 3

Peripheral macrophages invade the brain parenchyma embryonically following in utero electroporation. a E15.5 wild-type Iba1 and IgG expression show even distribution of Iba1+ cells throughout the brain parenchyma and IgG+ cells lining the periphery of the brain (asterisk). Higher magnification images of E15.5 wild-type Iba1 and IgG expression in the embryonic hypothalamus (a’, a”) and cortex (a”’). b E15.5 pCIG2 IUE (E14.5) brains highlight Iba1 and IgG expression. Iba1+ cells are evenly distributed throughout the brain parenchyma, while IgG cells are present both lining the ventricles in the brain parenchyma and surrounding the periphery of the brain (asterisk). Higher magnification images of E15.5 pCIG2 IUE (E14.5) Iba1 and IgG expression in the embryonic hypothalamus (b’, b”) and cortex (b”’). LV, lateral ventricle; 3V, third ventricle. Dashed lines outline the ventricles and pial surface and mark the division between the thalamus and hypothalamus. White arrows mark Iba1+ single-positive (a”, a”’, b”) cells, and white arrowheads mark Iba1+/IgG+ double-positive (a”’, b”, b”’) cells. Scale bar represents 250 μm (a–b”’). c Quantification of Iba1+/IgG+ cells within the parenchyma of the hypothalamus in IUE brains as compared to wild-type brains (mean ± SEM; wild-type n = 3, IUE n = 3; p = 0.0067)