Unchanged apoptosis and neuroinflammatory responses in Pen-2 cKO mice. A, TUNEL staining. No TUNEL⁺ cells were observed in the cortex or the thalamus in control and Pen-2 cKO mice at P11 and P14. B, C, IHC on NeuN and Iba1. There was comparable immunoreactivity of NeuN (B) or Iba1 (C) between control and Pen-2 cKO mice. There was no significant difference on averaged number of NeuN⁺ (B) or Iba1⁺ (C) cells (in 1 mm² area) in the cortex of control and Pen-2 cKO mice at P14 (n = 4 per group). Scale bars: A, 50 µm; B, C, 100 µm. NS, not significant.