Proteome profiling of different rat brain regions reveals the modulatory effect of prolonged maternal separation on proteins involved in cell death-related processes

Proteome Profiling of Rat Brain Cortical Changes during Early Postnatal Brain Development

Label-free quantitation (LFQ) was applied to proteome profiling of rat brain cortical development during the early postnatal period. Male and female rat brain extracts were prepared using a convenient, detergent-free sample preparation technique at postnatal days (PND) 2, 8, 15, and 22. The PND protein ratios were calculated using Proteome Discoverer, and the PND protein change profiles were constructed separately for male and female animals for key presynaptic, postsynaptic, and adhesion brain proteins. The profiles were compared to the analogous profiles assembled from the published mouse and rat cortex proteomic data, including the fractionated-synaptosome data. The PND protein-change trendlines, Pearson correlation coefficient (PCC), and linear regression analysis of the statistically significant PND protein changes were used in the comparative analysis of the datasets. The analysis identified similarities and differences between the datasets. Importantly, there were significant similarities in the comparison of the rat cortex PND (current work) vs mouse (previously published) PND profiles, although in general, a lower abundance of synaptic proteins in mice than in rats was found. The male and female rat cortex PND profiles were expectedly almost identical (98-99% correlation by PCC), which also substantiated this LFQ nanoflow liquid chromatography-high-resolution mass spectrometry approach.

Effect of Family Integrated Care on maternal stress in preterm infants in the Neonatal Intensive Care Unit: A bi-center experience

AIM

To compare the effect of family integrated care (FICare) on maternal stress in preterm infants with traditional non-parent neonatal intensive care unit (NICU) care.

METHODS

We continuously enrolled mothers and their preterm infants from two NICUs between August 2014 and April 2017; while one NICU applied the FICare model (FICare group) and the other performed standard non-parent care model (control group). Maternal stress was evaluated by the Parental Stress Scale: NICU (PSS: NICU) on admission and right before the discharge. A generalized linear model to adjust for potential confounders. Subgroup analysis was also performed for comparisons between two groups.

RESULTS

A total of 215 mothers with preterm infants were included in this study, among whom 118 (54.88%) were in FICare group and 97 (45.12%) were in control group. The mean PSS: NICU score was 117.36 ± 26.27 on admission with no difference between two groups. Before being discharged home, the PSS: NICU score of parents in both groups was significantly reduced, with the score of FICare group was significantly lower than that of control group. In all sub-domains of PSS: NICU score as sights and sounds, baby looks and behavior score, and parental role, the scores of FICare group were significantly lower than control group.

CONCLUSIONS

There was a simultaneous decrease of maternal stress for NICU preterm infants. FICare further facilitates reducing the maternal stress. It shall be encouraged to apply FICare model in NICUs.

Methylmercury exposure during prenatal and postnatal neurodevelopment promotes oxidative stress associated with motor and cognitive damages in rats: an environmental-experimental toxicology study

The environmental contamination by methylmercury (MeHg) is a major concern for public health. The effects of MeHg in the central nervous system (CNS) of adult animals have been extensively investigated; however, little is known about the effects of MeHg exposure during intrauterine and lactation periods on motor and cognitive functions of adolescent rats. Therefore, this study aimed to investigate the effect of MeHg exposure during intrauterine life and lactation on both motor and cognitive functions of offspring rats. Ten female Wistar rats were exposed to 40 μg/kg/day of MeHg through cookie treats from the first day of pregnancy until the last day of breastfeeding. Both motor and cognitive functions of offspring male rats were assessed by open field, rotarod, and step-down inhibitory avoidance tests. Forty-one days after birth, the hippocampus and cerebellum were collected to determine total Hg content, antioxidant capacity against peroxyl radicals (ACAP), reduced glutathione (GSH) levels, lipid peroxidation (LPO), and nitrite levels. MeHg exposure during CNS development increased Hg levels in both hippocampal and cerebellar parenchymas, triggered oxidative stress throughout ACAP and GSH decrease, increased LPO and nitrite levels. These alterations resulted in reduced spontaneous and stimulated locomotion and short- and long-term memory deficits. Therefore, damages triggered by MeHg exposure during intrauterine life and lactation had detrimental effects on oxidative biochemistry and motor and cognitive functions of offspring rats.

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The MeHg exposure during CNS development increased mercury levels in hippocampal and cerebellar parenchyma.

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The MeHg intoxication during pregnancy and lactation impairs the redox status of hippocampus and cerebellum of the offspring.

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MeHg exposure causes behavioral effects in motor ability and cognition of offspring rats.

Sex Differences in Affective Dysfunction and Alterations in Parvalbumin in Rodent Models of Early Life Adversity

The early life environment markedly influences brain and behavioral development, with adverse experiences associated with increased risk of anxiety and depressive phenotypes, particularly in females. Indeed, early life adversity (ELA) in humans (i.e., caregiver deprivation, maltreatment) and rodents (i.e., maternal separation, resource scarcity) is associated with sex-specific emergence of anxious and depressive behaviors. Although these disorders show clear sex differences in humans, little attention has been paid toward evaluating sex as a biological variable in models of affective dysfunction; however, recent rodent work suggests sex-specific effects. Two widely used rodent models of ELA approximate caregiver deprivation (i.e., maternal separation) and resource scarcity (i.e., limited bedding). While these approaches model aspects of ELA experienced in humans, they span different portions of the pre-weaning developmental period and may therefore differentially contribute to underlying mechanistic risk. This is borne out in the literature, where evidence suggests differences in trajectories of behavior depending on the type of ELA and/or sex; however, the neural underpinning of these differences is not well understood. Because anxiety and depression are thought to involve dysregulation in the balance of excitatory and inhibitory signaling in ELA-vulnerable brain regions (e.g., prefrontal cortex, amygdala, hippocampus), outcomes are likely driven by alterations in local and/or circuit-specific inhibitory activity. The most abundant GABAergic subtypes in the brain, accounting for approximately 40% of inhibitory neurons, contain the calcium-binding protein Parvalbumin (PV). As PV-expressing neurons have perisomatic and proximal dendritic targets on pyramidal neurons, they are well-positioned to regulate excitatory/inhibitory balance. Recent evidence suggests that PV outcomes following ELA are sex, age, and region-specific and may be influenced by the type and timing of ELA. Here, we suggest the possibility of a combined role of PV and sex hormones driving differences in behavioral outcomes associated with affective dysfunction following ELA. This review evaluates the literature across models of ELA to characterize neural (PV) and behavioral (anxiety- and depressive-like) outcomes as a function of sex and age. Additionally, we detail a putative mechanistic role of PV on ELA-related outcomes and discuss evidence suggesting hormone influences on PV expression/function which may help to explain sex differences in ELA outcomes.

Lactobacillus paracasei ameliorates cognitive impairment in high-fat induced obese mice via insulin signaling and neuroinflammation pathways

Long-term consumption of a high-fat diet (HFD) can cause glucose and lipid metabolism disorders, damage the brain and nervous system and result in cognitive impairment. The objective of this study was to investigate the preventative effects of Lactobacillus paracasei (Jlus66, a probiotic extracted from cheese in Northeast China) on cognitive impairment associated with HFD. The water maze was used to compare memory changes in mice fed HFD with or without Jlus66. Hippocampal tissue morphology was examined using H&E staining. The expression of neurotrophic factors BDNF, PSD95 and SNAP25, insulin resistance related proteins IRS-1, AKT and GSK3β, and inflammatory related proteins JNK and p38 were detected using western blotting. The results showed that Jlus66 significantly increased the expression of BDNF, PSD95 and SNAP25 (p < 0.01, respectively), increased expression of p-AKT (p < 0.05), p-IRS-1Y612 and p-GSK3β (p < 0.01, respectively), and reduced the expression of p-IRS-1S307, p-JNK and p-p38 (p < 0.05) compared with the HFD group. We conclude that Jlus66 can ameliorate cognitive impairment via insulin signaling and neuroinflammation pathways.

Lactobacillus paracasei ameliorates cognitive impairment in high-fat induced obese mice via insulin signaling and neuroinflammation pathways

Long-term consumption of a high-fat diet (HFD) can cause glucose and lipid metabolism disorders, damage the brain and nervous system and result in cognitive impairment.