Figure 3.

Effects of hypoxic and enriched environment on SST, RLN, and VIP-immunopositive interneurons in neocortex. A, Immunolabeling with EGFP, RLN, and SST antibodies in P47 cortex from GAD67-EGFP mice, illustrating the presence of different subpopulations of interneurons: EGFP⁺/SST⁺/RLN⁻ (small closed arrows), EGFP⁺/SST/⁺/RLN⁺ (arrowheads), and EGFP⁺/RLN⁺/SST⁻ (open arrow). Asterisk indicates an EGFP⁻/RLN⁺/SST⁻ cell. B, C, Stereological quantification of EGFP⁺ cells coexpressing SST and/or RLN at P15 (B) and at P47 (C). Both SST⁺/RLN⁻ and SST⁺/RLN⁺ interneurons were decreased in hypoxic-reared mice, but while the first recovered to control levels with subsequent enrichment, SST⁺/RLN⁺ interneurons did not recover with subsequent enrichment. In contrast, RLN⁺/SST⁻ interneurons increased after hypoxia and were also normalized with enriched environment at P47. D, Decreased number VIP⁺ interneurons in P15 hypoxic cortex (Ctx) shown by immunostaining with VIP antibodies; stereological quantification shown in F. E, Higher magnification image of supragranular Ctx demonstrating that all VIP⁺ cells coexpress GAD67-EGFP at P15. G, Stereological quantification of VIP⁺ cells in neocortex at P47 showing that VIP⁺ cells recovered spontaneously and there was no further effect of enriched environment. NX NE, normoxic nonenriched; NX EN, normoxic enriched; HX NE, hypoxic nonenriched; HX EN, hypoxic enriched. Scale bars: 20 μm. Asterisks denote significant differences from all other groups at p < 0.05.