Long-Term Effects of Maternal Deprivation on Redox Regulation in Rat Brain: Involvement of NADPH Oxidase

Abstract

Maternal deprivation (MD) causes perinatal stress, with subsequent behavioral changes which resemble the symptoms of schizophrenia. The NADPH oxidase is one of the major generators of reactive oxygen species, known to play a role in stress response in different tissues. The aim of this study was to elucidate the long-term effects of MD on the expression of NADPH oxidase subunits (gp91^phox, p22^phox, p67^phox, p47^phox, and p40^phox). Activities of cytochrome C oxidase and respiratory chain Complex I, as well as the oxidative stress parameters using appropriate spectrophotometric techniques were analyzed. Nine-day-old Wistar rats were exposed to a 24 h maternal deprivation and sacrificed at young adult age. The structures affected by perinatal stress, cortex, hippocampus, thalamus, and caudate nuclei were investigated. The most prominent findings were increased expressions of gp91^phox in the cortex and hippocampus, increased expression of p22^phox and p40^phox, and decreased expression of gp91^phox, p22^phox, and p47^phox in the caudate nuclei. Complex I activity was increased in all structures except cortex. Content of reduced glutathione was decreased in all sections while region-specific changes of other oxidative stress parameters were found. Our results indicate the presence of long-term redox alterations in MD rats.

Figure 1

Expression of NADPH oxidase subunits gp91^phox (a, b), p22^phox (a, c), p47^phox (a, d), p67^phox (a, e), and p40^phox (a, f) in the cortex, hippocampus, thalamus, and nucleus caudatus (P60) of control and MD animals. Results are presented as mean ± SEM; ^∗p < 0.05 versus control group; n = 4 animals per group.

Figure 2

Expression of Iba1 in the cortex, hippocampus, thalamus, and nucleus caudatus in control and MD animals (P60). Results are presented as mean ± SEM; ^∗p < 0.05 versus control group; n = 4 animals per group.

Figure 3

Representative immunohistochemical staining of Iba1 (green) in coronal sections of the cortex (a, b) and hippocampus (c, d) of control (a, c) and MD (b, d) rats; nuclear staining with DAPI (blue). Scale bars: 20 μm. (e) Numerical density of Iba1 immunostained cells in the cortex (CX) and hippocampus (HIPPO). Results are presented as mean ± SEM; ^∗p < 0.05 versus control group; n = 5 animals per group.

Figure 4

Level of GSH (a), activity of γ-GCL (b), activity of GPx (c), and activity of GR (d) in control and MD animals (P60) in synaptosomal fractions of different brain structures. Results are presented as mean ± SEM; ^∗p < 0.05 versus control group; n = 6 animals per group.

Figure 5

Expression of SOD1 (a) and SOD2 (b) in the cortex, hippocampus, thalamus, and nucleus caudatus in control and MD animals (P60). Results are presented as mean ± SEM; ^∗p < 0.05 versus control group; n = 4 animals per group.