Figure 2.

Effects of hypoxic rearing and environmental enrichment on PV-expressing interneurons. A, B, PV immunohistochemistry in the neocortex of normoxic (NX) and hypoxic (HX)-reared mice at P15 (A) and P47 (B); P47 groups of NX and HX mice were reared in standard, nonenriched (NE) or enriched (EN) environments from P21 until analysis. Stereological quantification of PV⁺ cells in P15 (C), P35 (D), and P47 (E) cortex (Ctx) for all four experimental groups. Rearing mice in HX decreased PV interneuron numbers in neocortex and subsequent EN normalized PV⁺ cell numbers (P35: main effect of hypoxia, p < 0.05; P47: main effect of hypoxia and enrichment, both p < 0.001). F–I, Hippocampal (Hp) PV immunolabeling (F) and stereological quantification of PV⁺ cells at P15 (G), 35 (H), and 47 (I). Rearing mice in HX decreased PV⁺ interneurons in the hippocampus at P15 but PV⁺ cells recovered spontaneously. Scale bars: 20 μm. Asterisks denote significant differences from all other groups at p < 0.05.