Long-term consequences of developmental exposure to aluminum in a suboptimal diet for growth and behavior of Swiss Webster mice

Tamarindus indica ameliorates behavioral and cytoarchitectural changes in the cerebellar cortex following prenatal aluminum chloride exposure in Wistar rats

Aluminium exposure has been linked with developmental neurotoxicity in humans and experimental animals. The study aimed to evaluate the ameliorative effect of Tamarindus indica on the developing cerebellar cortex, neurobehavior, and immunohistochemistry of the cerebellar cortex following prenatal aluminum chloride (AlCl₃) exposure. Pregnant timed Wistar rats were divided into 5 groups (n=4). Group I (negative control) was given distilled water, group II was treated with 200 mg/kg of AlCl₃, group III were given 200 mg/kg of AlCl₃ and 400 mg/kg of ethyl acetate leaf fraction of Tamarindus indica (EATI), group IV were given 200 mg/kg of AlCl₃ and 800 mg/kg of EATI, and group V were treated with 200 mg/kg of AlCl₃ s/c and 300 mg/kg of vitamin E for 14 days (prenatal day 7-21) via the oral route. Male pups (n=6) were randomly selected and taken for neurobehavioral studies, and humanely sacrificed via intraperitoneal injection of thiopental sodium. The cerebellum was removed, fixed and tissue processed for histological and immunohistochemical studies. The results revealed that prenatal AlCl₃ exposure impacted neurodevelopment and neurobehaviour among exposed pups. Prenatal AlCl₃ exposure was marked with delayed cytoarchitectural development of the cerebellar cortex and increased GFAP expression in the cerebellar cortex. On the other hand, treatment with EATI and vitamin E were marked with significant improvements. The present study therefore concluded treatment with EATI shows an ameliorative effect to prenatal AlCl₃ exposure.

Celastrol and thymoquinone alleviate aluminum chloride-induced neurotoxicity: Behavioral psychomotor performance, neurotransmitter level, oxidative-inflammatory markers, and BDNF expression in rat brain

Exposure to aluminum chloride (AlCl₃) induces progressive multiregional neurodegeneration in animal models by promoting oxidative stress and neuroinflammation. The current study was designed to assess the potential efficacy of the natural antioxidants celastrol and thymoquinone (TQ) for alleviating AlCl₃-induced psychomotor abnormalities and oxidative-inflammatory burden in male albino rats. Four treatment groups were compared: (i) a vehicle control group, (ii) a AlCL₃ group receiving daily intraperitoneal (i.p.) injection of AlCl₃ (10 mg/kg) for 6 weeks, (iii) a AlCl₃ plus TQ (10 mg/kg, i.p.) cotreatment group, and (iv) a AlCl₃ plus celastrol (1 mg/kg, i.p.) cotreatment group. Open-field, rotarod, and forced swimming tests were conducted to assess locomotor activity, motor coordination, anxiety-like behavior, and depressive-like behavior. Acetylcholine (ACh), dopamine, and serotonin levels were measured in brain homogenates. Malondialdehyde (MDA), total antioxidant capacity (TAC), and catalase activity were measured as oxidative stress markers, while tumor necrosis factor-α (TNF-α) and interlukin-6 (IL-6) expression levels were measured as inflammatory markers. Brain derived neurotrophic factor (BDNF) mRNA was measured as an index for the endogenous neuroprotective response. Daily AlCl₃ injection reduced free ambulation, impaired motor coordination, promoted anxiety- and depression-like behaviors, reduced whole-brain ACh, dopamine, and serotonin concentrations, increased MDA accumulation, reduced TAC, elevated TNF-α and IL-6, and suppressed BDNF mRNA expression. All of these effects were significantly reversed by TQ or celastrol cotreatment. Thus, TQ and celastrol may be promising treatments for AlCl₃-induced neurotoxicity as well as neurodegenerative diseases involving oxidative stress and neuroinflammation.

Reviewing the association between aluminum adjuvants in the vaccines and autism spectrum disorder

The manuscript reviews the association between aluminum adjuvants (AlAd) in vaccines and autism spectrum disorder (ASD). Aluminum (Al) is neurotoxic. Infants who have received AlAd in vaccines show a higher rate of ASD. The behavior of mice changes with Al injection. Patients suffering from ASD have higher concentrations of Al in their brains. Thus, AlAd is an etiologic factor in ASD. Immune efficacy led to the use of the AlAd in vaccines; however, the safety of those who are vaccinated with such vaccines has not been considered. The mechanisms of action of AlAd and the pharmacodynamics of injected AlAd used in vaccines are not well-characterized. The association between aluminum adjuvants in the vaccines and autism spectrum disorder is suggested by multiple lines of evidence.

Slc20a2-Deficient Mice Exhibit Multisystem Abnormalities and Impaired Spatial Learning Memory and Sensorimotor Gating but Normal Motor Coordination Abilities

BACKGROUND

Primary familial brain calcification (PFBC, OMIM#213600), also known as Fahr's disease, is a rare autosomal dominant or recessive neurodegenerative disorder characterized by bilateral and symmetrical microvascular calcifications affecting multiple brain regions, particularly the basal ganglia (globus pallidus, caudate nucleus, and putamen) and thalamus. The most common clinical manifestations include cognitive impairment, neuropsychiatric signs, and movement disorders. Loss-of-function mutations in SLC20A2 are the major genetic causes of PFBC.

OBJECTIVE

This study aimed to investigate whether Slc20a2 knockout mice could recapitulate the dynamic processes and patterns of brain calcification and neurological symptoms in patients with PFBC. We comprehensively evaluated brain calcifications and PFBC-related behavioral abnormalities in Slc20a2-deficient mice.

METHODS

Brain calcifications were analyzed using classic calcium-phosphate staining methods. The Morris water maze, Y-maze, and fear conditioning paradigms were used to evaluate long-term spatial learning memory, working memory, and episodic memory, respectively. Sensorimotor gating was mainly assessed using the prepulse inhibition of the startle reflex program. Spontaneous locomotor activity and motor coordination abilities were evaluated using the spontaneous activity chamber, cylinder test, accelerating rotor-rod, and narrowing balance beam tests.

RESULTS

Slc20a2 homozygous knockout (Slc20a2-HO) mice showed congenital and global developmental delay, lean body mass, skeletal malformation, and a high proportion of unilateral or bilateral eye defects. Brain calcifications were detected in the hypothalamus, ventral thalamus, and midbrain early at postnatal day 80 in Slc20a2-HO mice, but were seldom found in Slc20a2 heterozygous knockout (Slc20a2-HE) mice, even at extremely old age. Slc20a2-HO mice exhibited spatial learning memory impairments and sensorimotor gating deficits while exhibiting normal working and episodic memories. The general locomotor activity, motor balance, and coordination abilities were not statistically different between Slc20a2-HO and wild-type mice after adjusting for body weight, which was a major confounding factor in our motor function evaluations.

CONCLUSION

The human PFBC-related phenotypes were highly similar to those in Slc20a2-HO mice. Therefore, Slc20a2-HO mice might be suitable for the future evaluation of neuropharmacological intervention strategies targeting cognitive and neuropsychiatric impairments.

Early-life exposure to aluminum and fine motor performance in infants: a longitudinal study

BACKGROUND

Aluminum (Al) is a well-established neurotoxicant. However, little is known about its effects on the neurodevelopment of infants.

OBJECTIVES

To examine early-life exposure to Al in relation to neurodevelopment in healthy infants.

METHODS

Nail Al concentrations were measured among 747 newborn babies within 6 months of delivery in the Shanghai Birth Cohort. Neurodevelopment was assessed using Ages and stages questionnaire (third edition, ASQ-3) at ages 6 and 12 months. General linear regression models were performed to estimate the associations between Al concentrations and ASQ-3 scores.

RESULTS

After adjustment for potential confounders, early-life exposure to Al was not associated with any neurodevelopmental performance at age 6 months. However, Al level was associated with an increased risk of having a low fine motor score (quartile 4 vs. quartile 1, mean difference (MD): -1.63; 95% confidence interval (CI): -3.22, -0.05; P-trend < 0.01) at 12 months. No association was found for communication, gross motor, problem-solving, or personal-social score at 12 months.

SIGNIFICANCE

Early-life exposure to Al may be associated with poor fine motor skills in a dose-response manner among apparently healthy infants at age 12 months.

The REACH registration process: A case study of metallic aluminium, aluminium oxide and aluminium hydroxide

The European Union's REACH Regulation requires determination of potential health and environmental effects of chemicals in commerce. The present case study examines the application of REACH guidance for health hazard assessments of three high production volume (HPV) aluminium (Al) substances: metallic aluminium, aluminium oxide, and aluminium hydroxide. Among the potential adverse health consequences of aluminium exposure, neurotoxicity is one of the most sensitive targets of Al toxicity and the most critical endpoint. This case study illustrates integration of data from multiple lines of evidence into REACH weight of evidence evaluations. This case study then explains how those results support regulatory decisions on classification and labelling. Challenges in the REACH appraisal of Al compounds include speciation, solubility and bioavailability, application of assessment factors, read-across rationale and differences with existing regulatory standards. Lessons learned from the present case study relate to identification and evaluation of toxicologic and epidemiologic data; assessing data relevance and reliability; development of derived no-effect levels (DNELs); addressing data gaps and preparation of chemical safety reports.

Aluminum reproductive toxicity: a summary and interpretation of scientific reports

Publications addressing aluminum (Al)-induced reproductive toxicity were reviewed. Key details were compiled in summary tables. Approximate systemic Al exposure, a measure of bioavailability, was calculated for each exposure, based on the Al percentage in the dosed Al species, Al bioavailability, and absorption time course reports for the exposure route. This was limited to laboratory animal studies because no controlled-exposure human studies were found. Intended Al exposure was compared to unintended dietary Al exposure. The considerable and variable Al content of laboratory animal diets creates uncertainty about reproductive function in the absence of Al. Aluminum-induced reproductive toxicity in female mice and rats was evident after exposure to ≥25-fold the amount of Al consumed in the diet. Generally, the additional daily Al systemic exposure of studies that reported statistically significant results was greater than 100-fold above the typical human daily Al dietary consumption equivalent. Male reproductive endpoints were significantly affected after exposure to lower levels of Al than females. Increased Al intake increased fetus, placenta, and testes Al concentrations, to a greater extent in the placenta than fetus, and, in some cases, more in the testes than placenta. An adverse outcome pathway (AOP) was constructed for males based on the results of the reviewed studies. The proposed AOP includes oxidative stress as the molecular initiating event and increased malondialdehyde, DNA and spermatozoal damage, and decreased blood testosterone and sperm count as subsequent key events. Recommendations for the design of future studies of reproductive outcomes following exposure to Al are provided.

Aggregated aluminium exposure: risk assessment for the general population

Aluminium is one of the most abundant elements in earth's crust and its manifold uses result in an exposure of the population from many sources. Developmental toxicity, effects on the urinary tract and neurotoxicity are known effects of aluminium and its compounds. Here, we assessed the health risks resulting from total consumer exposure towards aluminium and various aluminium compounds, including contributions from foodstuffs, food additives, food contact materials (FCM), and cosmetic products. For the estimation of aluminium contents in foodstuff, data from the German "Pilot-Total-Diet-Study" were used, which was conducted as part of the European TDS-Exposure project. These were combined with consumption data from the German National Consumption Survey II to yield aluminium exposure via food for adults. It was found that the average weekly aluminium exposure resulting from food intake amounts to approx. 50% of the tolerable weekly intake (TWI) of 1 mg/kg body weight (bw)/week, derived by the European Food Safety Authority (EFSA). For children, data from the French "Infant Total Diet Study" and the "Second French Total Diet Study" were used to estimate aluminium exposure via food. As a result, the TWI can be exhausted or slightly exceeded-particularly for infants who are not exclusively breastfed and young children relying on specially adapted diets (e.g. soy-based, lactose free, hypoallergenic). When taking into account the overall aluminium exposure from foods, cosmetic products (cosmetics), pharmaceuticals and FCM from uncoated aluminium, a significant exceedance of the EFSA-derived TWI and even the PTWI of 2 mg/kg bw/week, derived by the Joint FAO/WHO Expert Committee on Food Additives, may occur. Specifically, high exposure levels were found for adolescents aged 11-14 years. Although exposure data were collected with special regard to the German population, it is also representative for European and comparable to international consumers. From a toxicological point of view, regular exceedance of the lifetime tolerable aluminium intake (TWI/PTWI) is undesirable, since this results in an increased risk for health impairments. Consequently, recommendations on how to reduce overall aluminium exposure are given.

Aluminium toxicosis: a review of toxic actions and effects

Aluminium (Al) is frequently accessible to animal and human populations to the extent that intoxications may occur. Intake of Al is by inhalation of aerosols or particles, ingestion of food, water and medicaments, skin contact, vaccination, dialysis and infusions. Toxic actions of Al induce oxidative stress, immunologic alterations, genotoxicity, pro-inflammatory effect, peptide denaturation or transformation, enzymatic dysfunction, metabolic derangement, amyloidogenesis, membrane perturbation, iron dyshomeostasis, apoptosis, necrosis and dysplasia. The pathological conditions associated with Al toxicosis are desquamative interstitial pneumonia, pulmonary alveolar proteinosis, granulomas, granulomatosis and fibrosis, toxic myocarditis, thrombosis and ischemic stroke, granulomatous enteritis, Crohn's disease, inflammatory bowel diseases, anemia, Alzheimer's disease, dementia, sclerosis, autism, macrophagic myofasciitis, osteomalacia, oligospermia and infertility, hepatorenal disease, breast cancer and cyst, pancreatitis, pancreatic necrosis and diabetes mellitus. The review provides a broad overview of Al toxicosis as a background for sustained investigations of the toxicology of Al compounds of public health importance.

Evaluating the reproductive toxicology of tannery effluent in male SWISS mice

The transformation of skin in-natura into leather in tannery industries generates large volumes of organic matter that attract small mammals. i.e., rodents living close to these facilities. Animals foraging in the backyards of such industries get exposed to the effluent produced by them; however, attention has not been given to the impacts of such exposure on the reproductive biology of these animals. Thus, our study assessed whether the direct exposure to this effluent for periods longer than 90 days leads to reproductive loss in male Swiss mice. We assessed animals' sexual behavior at the end of the experimental period and analyzed their testicular histology, as well as semen quality and volume, besides measuring pro-inflammatory markers and assessing the reproductive performance of the exposed animals. Based on the herein collected data, mice exposed to the gross effluent collected in the backyard of a tannery industry, as well as to the effluent diluted in 5% of water, presented behavioral and histological changes in the testes, disorganized germinal cells in the seminiferous tubules and inflammatory process in intertubular spaces. The inflammatory process resulted from increased proinflammatory cytokine (IFN-gamma and CCL2) concentrations in the testes, fact that explained the larger number of sperm abnormalities and the reduced number of produced sperms. These factors, along with the previously reported changes, may have led to the low reproductive performance of animals exposed to the tested pollutant, which was assessed through the lethal dominant test. This pioneering article addressed the reproductive impact caused by the direct exposure of small rodents to tannery effluents. The research helped better understanding how these pollutants can influence natural ecosystems.

Impact of Prenatal and Postnatal Treatment of Sodium Fluoride and Aluminum Chloride on Some Hormonal and Sensorimotor Aspects in Rats

In most communities, there is a constant exposure to environmental pollutants with probable negative impact on the development of the nervous system. Among these pollutants are the sodium fluoride (NaF) and aluminum chloride (AlCl₃) which may represent a real threat to the proper functioning of the brain. This study comprises two fundamentally different strategies; in the first one, pregnant rats were administered a daily dose of NaF (0.15 g /L) or AlCl₃ (500 mg/L) in the drinking water either separately or in combination with each other from day 6 of gestation until just after weaning. In the second approach, the male rats born to mothers exposed to the pollutants were divided into two groups. In the first, rats were continued to be treated with the same pollutants administered to them in the drinking water at the same dose level until the age of 70 days. The rats of the second group were supplied with drinking water without either one of the pollutants for a similar period of time. The rats exposed to NaF separately or in combination with AlCl₃ during the prenatal life and subsequently through the postnatal stages exhibited disturbance in the locomotor activities. This was concomitant with alterations in plasma, PTH, ACTH, and estradiol levels. Additionally, the serum levels of LH and testosterone were altered in the two groups treated with sodium fluoride during the prenatal and up to the weaning periods or in the group which continued to have the NaF until day 70 after birth.

Reconsideration of the immunotherapeutic pediatric safe dose levels of aluminum

FDA regulations require safety testing of constituent ingredients in drugs (21 CFR 610.15). With the exception of extraneous proteins, no component safety testing is required for vaccines or vaccine schedules. The dosing of aluminum in vaccines is based on the production of antibody titers, not safety science. Here we estimate a Pediatric Dose Limit that considers body weight. We identify several serious historical missteps in past analyses of provisional safe levels of aluminum in vaccines, and provide updates relevant to infant aluminum exposure in the pediatric schedule considering pediatric body weight. When aluminum doses are estimated from Federal Regulatory Code given body weight, exposure from the current vaccine schedule are found to exceed our estimate of a weight-corrected Pediatric Dose Limit. Our calculations show that the levels of aluminum suggested by the currently used limits place infants at risk of acute, repeated, and possibly chronic exposures of toxic levels of aluminum in modern vaccine schedules. Individual adult exposures are on par with Provisional Tolerable Weekly Intake "limits", but some individuals may be aluminum intolerant due to genetics or previous exposures. Vaccination in neonates and low birth-weight infants must be re-assessed; other implications for the use of aluminum-containing vaccines, and additional limitations in our understanding of neurotoxicity and safety levels of aluminum in biologics are discussed.

Critical analysis of reference studies on the toxicokinetics of aluminum-based adjuvants

We reviewed the three toxicokinetic reference studies commonly used to suggest that aluminum (Al)-based adjuvants are innocuous. A single experimental study was carried out using isotopic 26Al (Flarend et al., Vaccine, 1997). This study used aluminum salts resembling those used in vaccines but ignored adjuvant uptake by cells that was not fully documented at the time. It was conducted over a short period of time (28days) and used only two rabbits per adjuvant. At the endpoint, Al elimination in the urine accounted for 6% for Al hydroxide and 22% for Al phosphate, both results being incompatible with rapid elimination of vaccine-derived Al in urine. Two theoretical studies have evaluated the potential risk of vaccine Al in infants, by reference to an oral "minimal risk level" (MRL) extrapolated from animal studies. Keith et al. (Vaccine, 2002) used a high MRL (2mg/kg/d), an erroneous model of 100% immediate absorption of vaccine Al, and did not consider renal and blood-brain barrier immaturity. Mitkus et al. (Vaccine, 2011) only considered solubilized Al, with erroneous calculations of absorption duration. Systemic Al particle diffusion and neuro-inflammatory potential were omitted. The MRL they used was both inappropriate (oral Al vs. injected adjuvant) and still too high (1mg/kg/d) regarding recent animal studies. Both paucity and serious weaknesses of reference studies strongly suggest that novel experimental studies of Al adjuvants toxicokinetics should be performed on the long-term, including both neonatal and adult exposures, to ensure their safety and restore population confidence in Al-containing vaccines.

Systemic Inflammation in C57BL/6J Mice Receiving Dietary Aluminum Sulfate; Up-Regulation of the Pro-Inflammatory Cytokines IL-6 and TNFα, C-Reactive Protein (CRP) and miRNA-146a in Blood Serum

A number of experimental investigations utilizing different murine species have previously reported: (i) that standard mouse-diets supplemented with physiologically realistic amounts of neurotoxic metal salts substantially induce pro-inflammatory signaling in a number of murine tissues; (ii) that these diet-stimulated changes may contribute to a systemic inflammation (SI), a potential precursor to neurodegenerative events in both the central and the peripheral nervous system (CNS, PNS); and (iii) that these events may ultimately contribute to a chronic and progressive inflammatory neurodegeneration, such as that which is observed in Alzheimer’s disease (AD) brain. In these experiments we assayed for markers of SI in the blood serum of C57BL/6J mice after 0, 1, 3 and 5 months of exposure to a standard mouse diet that included aluminum-sulfate in the food and drinking water, compared to age-matched controls receiving magnesium-sulfate or no additions. The data indicate that the SI markers that include the pro-inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor alpha (TNFα), the acute phase reactive protein C-reactive protein (CRP) production and a triad of pro-inflammatory microRNAs (miRNA-9, miRNA-125b and miRNA-146a) all increase in the serum after aluminum-sulfate exposure. For the first time these results suggest that ad libitum exposure to aluminum-sulfate at physiologically realistic concentrations, as would be found in the human diet over the long term, may predispose to SI and the potential development of chronic, progressive, inflammatory neurodegeneration with downstream pathogenic consequences.

Conditional Loss of Arx From the Developing Dorsal Telencephalon Results in Behavioral Phenotypes Resembling Mild Human ARX Mutations

Mutations in the Aristaless-Related Homeobox (ARX) gene cause structural anomalies of the brain, epilepsy, and neurocognitive deficits in children. During forebrain development, Arx is expressed in both pallial and subpallial progenitor cells. We previously demonstrated that elimination of Arx from subpallial-derived cortical interneurons generates an epilepsy phenotype with features overlapping those seen in patients with ARX mutations. In this report, we have selectively removed Arx from pallial progenitor cells that give rise to the cerebral cortical projection neurons. While no discernable seizure activity was recorded, these mice exhibited a peculiar constellation of behaviors. They are less anxious, less social, and more active when compared with their wild-type littermates. The overall cortical thickness was reduced, and the corpus callosum and anterior commissure were hypoplastic, consistent with a perturbation in cortical connectivity. Taken together, these data suggest that some of the structural and behavioral anomalies, common in patients with ARX mutations, are specifically due to alterations in pallial progenitor function. Furthermore, our data demonstrate that some of the neurobehavioral features found in patients with ARX mutations may not be due to on-going seizures, as is often postulated, given that epilepsy was eliminated as a confounding variable in these behavior analyses.

Accelerated tau aggregation, apoptosis and neurological dysfunction caused by chronic oral administration of aluminum in a mouse model of tauopathies

To clarify whether long-term oral ingestion of aluminum (Al) can increase tau aggregation in mammals, we examined the effects of oral Al administration on tau accumulation, apoptosis in the central nervous system (CNS) and motor function using tau transgenic (Tg) mice that show very slowly progressive tau accumulation. Al-treated tau Tg mice had almost twice as many tau-positive inclusions in the spinal cord as tau Tg mice without Al treatment at 12 months of age, a difference that reached statistical significance, and the development of pretangle-like tau aggregates in the brain was also significantly advanced from 9 months. Al exposure did not induce any tau pathology in wild-type (WT) mice. Apoptosis was observed in the hippocampus in Al-treated tau Tg mice, but was virtually absent in the other experimental groups. Motor function as assessed by the tail suspension test was most severely impaired in Al-treated tau Tg mice. Given our results, chronic oral ingestion of Al may more strongly promote tau aggregation, apoptosis and neurological dysfunction if individuals already had a pathological process causing tau aggregation. These findings may also implicate chronic Al neurotoxicity in humans, who frequently have had mild tau pathology from a young age.

Impact of aluminum sub-chronic toxicity on body weight and recognition memory of wistar rat

The aims of this study was to investigate the impact of aluminum nitrate administered in drinking water during 90 days (sub-chronic toxicity), on body weight gain, motor activity, brain aluminum accumulation and especially in recognition memory of wistar rats. Two groups of young female wistar rats were used. Treated rats received (80 mg L(-1)) of aluminum nitrate diluted in drinking water, while control rats received a drinking water only, for 3 months. An evolution of body weight, a motor activity, object recognition memory (NOR) and brain aluminum concentration has been evaluated. The body weight was taken weekly, whereas the memory abilities and the motor activity are measured once every fortnight alternatively, by submitting rats to the open field test and to the novel object recognizing memory test. The results have showed a significant decrease in rats' body weight (p < 0.05). Though, no significance was registered for motor activity. Nevertheless, a high significance is showed for recognition memory compared to control rats (p < 0.01), especially at the end of testing period, even the difference between control and aluminium treated rats in brain aluminum levels was not significant.

Concurrent exposure to aluminum and stress during pregnancy in rats: Effects on postnatal development and behavior of the offspring

The present study was conducted to assess the potential combined influence of maternal restraint stress and aluminum (Al) exposure on postnatal development and behavior in the offspring of exposed rats. Female rats were concurrently exposed to 0 (control group), 50 or 100 mg/kg/day of Al administered as Al nitrate nonahydrate in drinking water with citric acid (355 or 710 mg/kg/day) for a period of 15 days prior to mating with untreated males. Aluminum exposure was maintained throughout the gestational, lactational and post-weaning periods. On days 6-20 of gestation, one-half of the pregnant animals in each group were restrained for 2 h/day. Food consumption and maternal body weight were decreased in the groups exposed to restraint only or combined with the highest Al dose. All of the animals were allowed to deliver and wean their offspring. The pups were evaluated for physical development and neuromotor maturation. Moreover, open-field activity, passive avoidance, and spatial learning in a water maze were also determined on postnatal days 30, 35 and 60, respectively. Body weight of pups treated with 100 mg/kg/day of Al was decreased relative to controls from postnatal day 12 through 21, sexual maturation was delayed in Al treated females and in males exposed to 100 mg/kg/day. Forelimb grip strength was reduced in males exposed to 100 mg/Al/kg/day and in females exposed to this Al dose plus prenatal restraint. Learning in a passive avoidance task indicated facilitated performance for Al treated rats at 100 mg/kg/day combined with prenatal restraint as evidenced by longer avoidance latencies, while learning in a water maze task showed a shorter latency to find the platform on acquisition day 2 for Al treated rats. However, no effects of Al on water maze performance were detected during the retention probe trial in which the only effect noted was an increase in the platform quadrant swim time for the prenatal restraint group. In general terms, the results of the present study did not show a notable influence of maternal restraint on the Al-induced postnatal developmental and behavioral effects in the offspring of prenatally Al-exposed rats.

Modelling brain diseases in mice: the challenges of design and analysis

Genetically engineered mice have been generated to model a variety of neurological disorders. Several of these models have provided valuable insights into the pathogenesis of the relevant diseases; however, they have rarely reproduced all, or even most, of the features observed in the corresponding human conditions. Here, we review the challenges that must be faced when attempting to accurately reproduce human brain disorders in mice, and discuss some of the ways to overcome them. Building on the knowledge gathered from the study of existing mutants, and on recent progress in phenotyping mutant mice, we anticipate better methods for preclinical interventional trials and significant advances in the understanding and treatment of neurological diseases.

Cellular actions of Al at low (1.25 microM) concentrations in primary oligodendrocyte culture

At a physiologically relevant concentration (1.25 microM), aluminum had an activating effect on oligodendrocyte cell cultures, similar to that previously reported for other cell types. G protein-linked signal transduction was stimulated as indicated by enhanced production of IP3, and protein synthesis was increased. At this concentration Al did not promote cell damage but did enhance oxidative effects initiated by reactive oxygen species. Both AlCl(3) and Al transferrin (AlTf) had similar actions at equimolar concentrations. In vivo, physiological Al ion may act by common cellular pathways in diverse cell types. These effects may be relevant to Al toxicological, pharmacological (immunoadjuvant), and physiological effects.