Figure 1
Relationship between oxidative stress and PVI integrity in the ACC of 2–3 month-old animal models relevant to schizophrenia, autism and/or redox dysregulation. (a) Oxidative stress (assessed by the immunoreactivity intensity against 8-oxo-2'-deoxyguanosine (8-oxo-dG), a marker of mitochondrial DNA oxidation), number of PV-IR cells (PV cells) and number of PV cells enwrapped with a WFA-labeled PNN. # indicates models for which the presented data are already published elsewhere.39, 41 The references indexed below provide detailed descriptions of each investigated model and its control. 22q11: mice with a 22q11.2 deletion (LgDel/+)42 (n=7 animals per group); 15q13.3: mice with a 15q13.3 deletion (Df[h15q13]/+)43 (n=5, 7); 1q21: mice with a 1q21 deletion (Df[h1q21]/+) (from M Didriksen) (n=4 per group), SRR: serine racemace KO mice44 (n=5, 7); FMR1: FMR1 KO mice45 (n=7, 8); PV-GCLC: mice with conditional KO of GCLC (catalytic subunit of the key synthesizing enzyme of GSH) in PVIs40 (n=5 per group); GRIN2A: GRIN2A KO mice46 (n=7 per group); GCLM: GCLM KO mice47 (n=5 per group); GCLM GBR: GCLM KO mice treated with dopamine uptake inhibitor GBR12909 during postnatal development (P10-20)39 (n=5 per group); GRIN2A GBR: GRIN2A KO mice treated with GBR12909 during postnatal development (P10-20) (n=7 per group); ODS BSO: ODS rats treated with the specific inhibitor of GSH synthesis (BSO) during postnatal development (P5-16)38 (n=4 per group); NVHL: rats with a neonatal ventral hippocampal lesion41 (n=6, 7); MAM: rats treated on gestation day GD17 with MAM48 (n=4, 6); Poly(I:C): mice with a sub-threshold prenatal immune challenge (on GD9) with poly(I:C); +Str: poly(I:C)-treated mice stressed at preadolescence (P30-40)49 (n=5 per group). Data are depicted by the mean±s.d. (in red: animal models; in blue: their respective controls). *** P<0.001; ** P<0.01, * P<05. (b) Quantile density contours with linear regression (red) and smoothing spline (green) plots illustrating the relationships between changes in oxidative stress (8-oxo-dG-IR), in number of PV cells, and in number of PV cells with WFA-labeled PNN (PV cells+PNN) for all animal models relative to their respective controls (JMP11, SAS Institute, Cary, NC, USA). (c) As in (b) but illustrating the relationship between changes in number of PV cells+PNN and in number of PV cells for all animal models relative to their respective controls. Brief method description: perfused fixed brains from all animal models were sent to Lausanne where immunohistological preparation, image acquisition and analyses were performed blindly using the methods described previously.39 Three to four sections per animal were used for the analyses. Analyses of 8-oxo-dG-IR intensity, numbers of PV-IR cells and PV-IR cells surrounded with a WFA-labeled PNN were done in a region of interest comprising all layers of the ACC. Oxidative stress was assessed in all cells of ROI. Each animal model was compared with its own control animals. Only males were analyzed, except for the GRIN2A model where individuals from both sexes were used. On the basis of previously analyzed data,39 sample size was choosen to detect ~25% change in number of PV-IR cells and ~75% change in 8-oxo-dG intensity with a power of 80% at a significant α-value set to P=0.05. Statistical significance was tested by comparing means of the different models with their respective controls using the Dunnett’s test. When variances were not equal, we used the Welch’s test to give confidence and confirm the Dunnett’s test outcome. ACC, anterior cingulate cortex; BSO, buthionine sulphoximine; KO, knockout; MAM, methylazoxymethanol acetate; NVHL, neonatal ventral hippocampal lesion; ODS, osteogenic disorder Shionogi; PNN, perineuronal net; PV, parvalbumin; PV-IR, parvalbumin-immunoreactive; PVI, parvalbumin inhibitory interneuron; WFA, Wisteria floribunda agglutinin.
