Neonatal Oxidative Stress Impairs Cortical Synapse Formation and GABA Homeostasis in Parvalbumin-Expressing Interneurons

Figure 5

Delayed expression of synaptic markers after exposure to neonatal hyperoxia. Real-time PCR expression analysis of the synaptic markers: synapsin 1 (Syn1), synapsin 2 (Syn2), synaptotagmin 1 (Syt1), synaptotagmin2 (Syt2), and synaptophysin (Syp) at the age P7, P9, P11, P14, and P30. Gene expression of Syn1 was decreased in cortical samples of animals previously exposed to neonatal hyperoxia (P5-P7) at the ages P7, P9, P11, and P14 and returns to control level at P30 (a). At P7-P14, cortical RNA expression of Syn2 was decreased in hyperoxia animals compared to control litters. At P30, Syn2 expression returns to control level (b). RNA expression of Syt1 was reduced at P9 (c) in the hyperoxia group. Cortical expression of Syt2 was reduced at P11 in mice previously exposed to hyperoxia and returns to control level at P14 (d). At the ages P7, P9, and P11, cortical RNA expression of Syp was decreased in the hyperoxia group (e) (for qPCR: -8, -test, ; ; ). Immunohistochemical staining for parvalbumin (PVALB) and synapsin 1/2 (SYN1/2) of 10 μm coronal brain sections at the age P14 reveals SYN1/2 expression of cortical PVALB+ interneurons (f). Scale bar 20 μm.

(a)

(b)

(c)

(d)

(e)

(f)