Exposure to low doses of 137cesium and nicotine during postnatal development modifies anxiety levels, learning, and spatial memory performance in mice

Relationships between trace elements and cognitive and depressive behaviors in sprague dawley and wistar albino rats

Introduction: This study investigates the effects of social isolation on mental health and cognitive functions in Sprague Dawley (SD) and Wistar Albino (WIS) rat strains, prompted by the heightened awareness of such impacts amid the COVID-19 pandemic. This study aims to explore the impact of social isolation on memory, learning, and behavioral changes in middle-aged SD and WIS rat strains and to investigate cortical trace element levels, seeking potential correlations between these levels and the observed behavioral responses to social isolation. Methods: Four groups of 14-month-old male rats were established: control and isolated SDs and WIS rats (CONT-SD, ISO-SD, CONT-WIS, ISO-WIS). Morris Water Maze and Porsolt Forced Swimming tests were conducted for behavioral assessment. Following behavioral tests, rats were sacrificed under general anesthesia, and cortices were isolated for analysis of macro and trace element levels (ICP/MS). Results: In behavioral tests, CONT-SD rats exhibited superior performance in the Morris Water Maze test compared to CONT-WIS rats, but displayed increased depressive behaviors following social isolation, as evident in the Porsolt Forced Swimming test (p < 0.05). ISO-SD rats showed elevated levels of Co and Cu, along with reduced levels of Cs and As, compared to ISO-WIS rats. Moreover, isolation resulted in decreased Cu and Mo levels but increased Rb levels in WIS rats. Comparison of trace element levels in naïve groups from different strains revealed lower Zn levels in the WIS group compared to SD rats. Discussion: The findings suggest that the SD strain learns faster, but is more susceptible to depression after isolation compared to the WIS strain. Increased Co and Cu levels in ISO-SD align with previous findings, indicating potential trace element involvement in stress responses. Understanding these mechanisms could pave the way for preventive treatment strategies or therapeutic targets against the consequences of stressors, contributing to research and measures promoting a balanced diet to mitigate neurobehavioral abnormalities associated with social isolation in the future.

Maternal drinking behaviour and co-exposure from smoking during and after pregnancy in relation to the neurocognitive function of school-children in the rural Western Cape

BACKGROUND

Maternal substance use and its long-term effect on the neurocognitive functions of children is a global public health issue. Despite an increase in substance use in rural areas of low to middle-income countries, research is limited in these populations.

OBJECTIVE

We have therefore explored the effect of maternal drinking and smoking behaviors on the neurocognitive functioning of rural school children.

METHOD

A cross-sectional analysis on the determinants of current, past and gestational maternal alcohol use and gestational smoking on child neurocognitive functions was conducted on school-children (N = 482), embedded within the child health agricultural cohort (CapSA) study across seven schools in rural Western Cape, South Africa. Standardised neurocognitive assessment tools included the Cambridge Automated Neuropsychological Battery (CANTAB) and the KIDSCREEN-10 to measure health-related quality of life via a child questionnaire. Maternal smoking and drinking behaviour were captured using a parent/guardian questionnaire.

RESULTS

Of the 482 parents/guardians who completed the survey, 29 % reported current drinking 27 % reported past drinking and 10 % reported maternal gestational drinking, while 31 % reported gestational smoking. Significant associations were observed between past and current maternal drinking and child's reduced rapid visual processing accuracy in attention [β:-0.03; 95 % confidence interval (CI): -0.05;-0.004] and between maternal drinking during pregnancy and reduced child's spatial working memory (β: -0.59; CI: -1.02; -0.15). Heavy (>5 cigarettes per day) gestational smoking was associated with lowered child's learning in memory (β:-1.69; 95 % CI: -3.05; -0.33) and lower health-related quality of life (β: -3.41; CI: -6.64; -0.17). The odds of a child repeating a grade were 1.69 (CI: 2.81-1.02) for those exposed to maternal gestational smoking and 1.68 (CI: 3.31-0.85) for those exposed to maternal gestational drinking compared to those who were not exposed.

CONCLUSION

The consistent negative associations across all four maternal substance use proxies, six neurocognitive health outcomes and one health symptom is suggestive of adverse health effects, warranting longitudinal follow-up. Health policies to eliminate gestational substance use are recommended.

Memory and potential correlates among children in Jordan

BACKGROUND

Cognitive functioning hugely affects the performance of tasks of different complexity. Memory, one of the most important cognitive skills, allows children to practice and acquire necessary skills and knowledge and interact with the surrounding environment. Therefore, it is crucial to study the factors that influence the memory of children. The main purpose of his study was to investigate different variables related to memory in school aged children (5-9 years, N = 434).

METHODS

Parents of the participants provided information about child's daily behavior, child's school academic achievement, work and family income data and demographics. Memory skills in children were assessed by using the Leiter International Performance Scale -Revised.

RESULTS

The score of memory increased 2.53 points with upsurge in maternal occupation level, 3.08 points when the child ate breakfast and 4.51 points when the child daily slept nine hours and more. By contrast, increased family income and smoking by father resulted in decreased scores in memory.

CONCLUSION

Screening for and understanding of memory and relevant factors are vital for broad understanding of children's capabilities and weaknesses as well as for developing appropriate interventions.

Renal and hepatic effects following neonatal exposure to low doses of Bisphenol-A and 137Cs

137-Cesium (¹³⁷Cs) is one of the most important distributed radionuclides after a nuclear accident. Humans are usually co-exposed to various environmental toxicants, being Bisphenol-A (BPA) one of them. Exposure to IR and BPA in early life is of major concern, due to the higher vulnerability of developing organs. We evaluate the renal and hepatic effects of low doses of ionizing radiation (IR) and BPA. Sixty male mice (C57BL/6J) were randomly assigned to six experimental groups (n=10) and received a single subcutaneous dose of 0.9% saline solution, ¹³⁷Cs and/or BPA on postnatal day 10: control, BPA (25 μg/kgbw), Cs4000 (4000 Bq ¹³⁷Cs/kgbw), Cs8000 (8000 Bq ¹³⁷Cs/kgbw), BPA/Cs4000 and BPA/Cs8000. At the age of two months, urines (24h) and blood samples were collected from animals of each group to determine biochemical parameters. Finally, kidneys and liver were removed to quantify DNA damage (8-OHdG), as well as to determine CYP1A2 mRNA expression. Data suggest that both BPA and ¹³⁷Cs induced renal and liver damage evidenced by oxidative stress. However, when there is a co-exposure, it seems that there are compensatory mechanisms that may reverse the damage induced by each toxic itself. Notwithstanding, more studies are necessary to better understand the synergistic mechanisms behind.

Postnatal calpain inhibition elicits cerebellar cell death and motor dysfunction

Calpain-1 deletion elicits neurodevelopmental disorders, such as ataxia. However, the function of calpain in postnatal neurodevelopment and its mechanisms remain unknown. In this study, we revealed that postnatal intraperitoneal injection of various calpain inhibitors attenuated cerebellar cytosolic calpain activity. Moreover, postnatal application of calpeptin (2 mg/kg) apparently reduced spectrin breakdown, promoted suprachiasmatic nucleus circadian oscillatory protein (SCOP) accumulation in cerebellar tissue. In addition, application of calpeptin decreased phosphorylated protein kinase B (p-AKT) level (p<0.05), as well as total AKT level (p<0.05). We also evidenced that administration of calpeptin obviously increased phosphorylation of mammalian target of rapamycin (p-mTor) (p<0.01). Apoptosis of granular cells and activation of caspase-3 (p<0.01) were facilitated after calpain inhibition. Importantly, cell numbers of granular cells were reduced and motor function was remarkably impaired in 4-month-old rats receiving postnatal calpain inhibition. Taken together, our data implicated that calpain activity in the postnatal period was critical for the cerebellar development. Postnatal calpain inhibition causes cerebellar granular cell apoptosis and motor dysfunction, likely through SCOP/AKT and p-mTor signaling pathways.

Environmental exposure to low-doses of ionizing radiation. Effects on early nephrotoxicity in mice

Nuclear accidents of tremendous magnitude, such as those of Chernobyl (1986) and Fukushima (2011), mean that individuals living in the contaminated areas are potentially exposed to ionizing radiation (IR). However, the dose-response relationship for effects of low doses of radiation is not still established. The present study was aimed at investigating in mice the early effects of low-dose internal radiation exposure on the kidney. Adult male (C57BL/6J) mice were divided into three groups. Two groups received a single subcutaneous (s.c.) doses of cesium (¹³⁷Cs) with activities of 4000 and 8000Bq/kg bw. A third group (control group) received a single s.c. injection of 0.9% saline. To evaluate acute and subacute effects, mice (one-half of each group) were euthanized at 72h and 10 days post-exposure to ¹³⁷Cs, respectively. Urine samples were collected for biochemical analysis, including the measurement of F2-isoprostane (F2-IsoP) and kidney injury molecule-1 (KIM-1) levels. Moreover, the concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a sensitive marker of oxidative DNA damage, were measured in renal tissue. Urinary excretion of total protein significantly increased at 72h in mice exposed to Cs4000. Uric acid and lactate dehydrogenase (LDH) decreased significantly at both times post-exposure in animals exposed to Cs8000. After 72h and 10d of exposure to Cs4000, a significant increase in the γ-glutamil transferase (GGT) and N-acetyl-β-D-glucosaminidase (NAG) activities was observed. In turn, F2-IsoP levels increased -mainly in the Cs4000 group- at 72h post-exposure. Following irradiation (¹³⁷Cs), the highest level of KIM-1 was corresponded to the Cs4000 group at 72h. Likewise, the main DNA damage was detected in mice exposed to Cs4000, mainly at 10d after irradiation. The alterations observed in several biomarkers suggest an immediate renal damage following exposure to low doses of IR (given as ¹³⁷Cs). Further investigations are required to clarify the mechanisms involved in the internal IR-induced nephrotoxicity.