Increased Apoptosis in Subcortical Regions of The Visual Pathway in Offspring Born to Diabetic Rats.

OBJECTIVE: Diabetes in pregnancy is a prevalent disease that can affect the central nervous system of the fetus by hyperglycemia. This study aimed to investigate the impact of maternal diabetes on neuronal apoptosis in the superior colliculus (SC) and the lateral geniculate nucleus (LGN) in male neonates born to diabetic mothers. MATERIALS AND METHODS: In this experimental study, female adult rats were separated into three groups: control, diabetic (induced using an intraperitoneal injection of streptozotocin), and insulin-treated diabetic [diabetes controlled by subcutaneous neutral protamine hagedorn (NPH)-insulin injection]. Male neonates from each group were euthanized on 0, 7, and 14 postnatal days (P0, P7, and P14, respectively), and apoptotic cells were identified using TUNEL staining. RESULTS: The numerical density per unit area (NA) of apoptotic cells was significantly higher in SC and the dorsal LGN (dLGN) in neonates born to the diabetic rats compared to the control group at P0, P7, and P14. However, insulin treatment normalized the number of apoptotic cells. CONCLUSION: This study demonstrated that maternal diabetes increased apoptosis in dLGN and SC of male neonates at P0, P7, and P14.

Maternal diabetes decreases the expression of α2-adrenergic and M2 muscarinic receptors in the visual cortex of male rat neonates.

AIMS: This study investigates the impact of maternal diabetes on the expression of α2-adrenergic and M2 muscarinic receptors in the primary visual cortex of male offspring born to diabetic rats. MAIN METHODS: In adult female rats, a single dose of intraperitoneal streptozotocin (STZ) was used to induce diabetes (Diabetic group). Diabetes was controlled with insulin in the Insulin-treated group. Female rats in the control group received normal saline instead of STZ. Male newborns were euthanized at P0, P7, and P14, and the expression of α2-adrenergic and M2 muscarinic receptors in the primary visual cortex was determined using immunohistochemistry (IHC). KEY FINDINGS: The study showed that α2-adrenergic and M2 muscarinic receptors were significantly suppressed in all layers of the primary visual cortex of male neonates born to diabetic rats at P0, P7, and P14 compared to the control group. The highest expression was for the Con group at P14 and the lowest one was in the Dia group at P0 for both receptors. The insulin treatment in diabetic mothers modulated the expression of these receptors to normal levels in their newborns. SIGNIFICANCE: The results demonstrate maternal diabetes decreases the expression of α2-adrenergic and M2 muscarinic receptors in the primary visual cortex of male offspring born to diabetic rats. Insulin treatment can offset these effects of diabetes.

Expression of GABAAα1, GABAB1, and mGluR2 receptors in the lateral geniculate body of male neonates born to diabetic rats.

Objectives: Diabetes during gestation is one of the most common pregnancy complications and has adverse effects on offspring, including a negative impact on the offspring's central nervous system (CNS). Diabetes is a metabolic disease associated with visual impairment. Due to the importance of the lateral geniculate body (LGB) in the visual pathway, the present study examined the effect of maternal diabetes on the expression of gamma-aminobutyric acid (GABAAα1 and GABAB1) and metabotropic Glutamate (mGlu2) receptors in the LGB of male neonates of diabetic rats. Materials and Methods: Diabetes was induced in female adult rats by a single intraperitoneal dose of streptozotocin (STZ) 65 (mg/kg). In the Insulin-treated diabetic rats, diabetes was controlled by subcutaneous NPH-insulin injection daily. After mating and delivery, male offspring were killed by carbon dioxide gas inhalation at P0, P7, and P14 (postnatal days 0, 7, and 14). The expression of GABAAα1, GABAB1, and mGluR2 in the LGB of male neonates was determined using the immunohistochemistry (IHC) method. Results: The expression of GABAAα1 and GABAB1 was significantly reduced, whereas the expression of mGluR2 was markedly increased in the diabetic group compared with the control and insulin-treated groups at P0, P7, and P14. Conclusion: The results of the present study showed that induction of diabetes altered the expression of GABAAα1, GABAB1, and mGluR2 in the LGB of male neonates born to diabetic rats at P0, P7, and P14. Moreover, insulin treatment could reverse these effects of diabetes.

A new map of the rat isocortex and proisocortex: cytoarchitecture and M2 receptor distribution patterns.

Neurotransmitters and their receptors are key molecules in information transfer between neurons, thus enabling inter-areal communication. Therefore, multimodal atlases integrating the brain's cyto- and receptor architecture constitute crucial tools to understand the relationship between its structural and functional segregation. Cholinergic muscarinic M2 receptors have been shown to be an evolutionarily conserved molecular marker of primary sensory areas in the mammalian brain. To complement existing rodent atlases, we applied a silver cell body staining and quantitative in vitro receptor autoradiographic visualization of M2 receptors to alternating sections throughout the entire brain of five adult male Wistar rats (three sectioned coronally, one horizontally, one sagittally). Histological sections and autoradiographs were scanned at a spatial resolution of 1 µm and 20 µm per pixel, respectively, and files were stored as 8 bit images. We used these high-resolution datasets to create an atlas of the entire rat brain, including the olfactory bulb, cerebellum and brainstem. We describe the cyto- and M2 receptor architectonic features of 48 distinct iso- and proisocortical areas across the rat forebrain and provide their mean M2 receptor density. The ensuing parcellation scheme, which is discussed in the framework of existing comprehensive atlasses, includes the novel subdivision of mediomedial secondary visual area Oc2MM into anterior (Oc2MMa) and posterior (Oc2MMp) parts, and of lateral visual area Oc2L into rostrolateral (Oc2Lr), intermediate dorsolateral (Oc2Lid), intermediate ventrolateral (Oc2Liv) and caudolateral (Oc2Lc) secondary visual areas. The M2 receptor densities and the comprehensive map of iso-and proisocortical areas constitute useful tools for future computational and neuroscientific studies.

The effect of maternal diabetes on the expression of gamma-aminobutyric acid and metabotropic glutamate receptors in male newborn rats' inferior colliculi.

OBJECTIVES: Few studies have examined the molecular alterations in the auditory pathway of infants of diabetic mothers, notwithstanding the fact that maternal diabetes may have an impact on the development of the neonatal peripheral and central nervous systems. Male newborn rats were studied to determine how maternal diabetes affected the expression of gamma-aminobutyric acid (GABAAα1 and GABAB1) and metabotropic glutamate (mGlu2) receptors in the inferior colliculus (IC) in this research. METHODS: Female rats were given a single intraperitoneal injection of streptozotocin (STZ) at a 65 mg/kg dose to develop a model of diabetic mothers. The study population was split into sham, diabetes without treatment, and diabetes with insulin groups. Their male neonatal rats were anesthetized on P0, P7, and P14 after mating and delivery. The receptors' distribution pattern was studied using immunohistochemistry (IHC). RESULTS: Pairwise comparison in the groups revealed that the GABA receptors (Aα1 and B1) were significantly downregulated in the diabetes without treatment group (p<0.001). Furthermore, pairwise comparison in the groups indicated significant mGlu2 upregulation in the diabetes without treatment group (p<0.001). Regarding the concentration of all receptors, there was no discernible distinction between the diabetes with insulin and sham groups. CONCLUSIONS: This investigation showed that the concentration of GABAAα1 and GABAB1 receptors decreased significantly over time, whereas the concentration of mGlu2 receptors increased significantly over time in male neonatal rats born to streptozotocin-induced diabetic mothers.

Maternal diabetes decreases the expression of GABAAα1, GABAB1, and mGlu2 receptors in the visual cortex of male rat neonates.

AIMS: This study examines the impact of maternal diabetes on the expression of GABAB1, GABAAα1, and mGlu2 receptors in the primary visual cortex layers of male rat newborns. MAIN METHODS: In diabetic group (Dia), diabetes was induced in adult female rats using an intraperitoneal dose of Streptozotocin (STZ) 65 (mg/kg). Diabetes was managed by daily subcutaneous injection of NPH insulin in insulin-treated diabetic group (Ins). Control group (Con) received normal saline intraperitoneally rather than STZ. Male offspring born to each group of female rats were euthanized via CO2 inhalation at P0, P7, and P14 days after delivery and the expression of GABAB1, GABAAα1, and mGlu2 receptors in their primary visual cortex was determined using immunohistochemistry (IHC). KEY FINDINGS: The expression of GABAB1, GABAAα1, and mGlu2 receptors increased gradually with age in the male offspring born to Con group while the highest expression was detected in layer IV of the primary visual cortex. In Dia group newborns, the expression of these receptors was significantly reduced in all layers of the primary visual cortex at every three days. Insulin treatment in diabetic mothers restored the expression of these receptors to normal levels in their newborns. SIGNIFICANCE: The study indicates that diabetes reduces the expression of GABAB1, GABAAα1, and mGlu2 receptors in the primary visual cortex of male offspring born to diabetic rats at P0, P7, and P14. However, insulin treatment can counteract these effects.

The distribution pattern of M2 and Adrenergicα2 receptors on inferior colliculi in male newborns of diabetic rats.

AIMS: Despite the high prevalence of diabetes in the world, its possible effects throughut pregnancy on neonatal auditory nervous system development are still unknown. In the present research, maternal diabetes' impact on the M2 and Adrenergicα2 receptors expression in the inferior colliculus (IC) of male newborn rats was investigated. MAIN METHODS: Female rats were grouped into three: sham, insulin-treated diabetic, and diabetic. Diabetes was induced through streptozotocin (STZ) injection as one dose intraperitoneally (65 mg/kg). After mating and delivery, male rats were euthanized on P0, P7, and P14. Immunohistochemistry (IHC) was used to study the distribution pattern of receptors. KEY FINDINGS: The present study indicated that the expression of M2 receptors in the diabetic group was significantly increased in pairwise comparisons in the sham and diabetic treated with insulin groups (P < 0.001, each). The highest M2 expression was for the diabetic group on P14 and the lowest one was for the sham group on P0. The Adrenergicα2a receptors expression in the diabetic group was significantly reduced in pairwise comparisons in the sham and diabetic treated with insulin groups (P < 0.001, each). The highest Adrenergicα2a expression was for the sham group on P14 and the lowest one was for the diabetic group on P0. There was no significant difference between the sham and insulin groups regarding all receptors expression. SIGNIFICANCE: This study demonstrated a time-dependent significant decrease in Adrenergicα2a but a time-dependent significant increase in M2 receptors expression.

Developmental regulation and lateralization of N-methyl-d-aspartate (NMDA) receptors in the rat hippocampus.

N-methyl-d-aspartate receptors (NMDARs) are expressed abundantly in the brain and play a crucial role in the regulation of central nervous system (CNS) development, learning, and memory. During early neuronal development, NMDARs modulate neurogenesis, neuronal differentiation and migration, and synaptogenesis. The present study aimed to examine the developmental expression of NMDARs subunits, NR1 and NR2B, in the developing hippocampus of neonatal rats during the first two postnatal weeks. Fifty-four male offspring were randomly divided into three age groups, postnatal days (P) 0, 7, and 14. Real-time-PCR, western blotting, and immunohistochemistry (IHC) analyses were employed to examine and compare the hippocampal expression of the NMDA receptor subunits. The highest mRNA expression of NR1 and NR2B subunits was observed at P7, regardless of its laterality. The mRNA expression of both subunits in the right hippocampus was significantly higher than that of the left one at P0 and P7. Similarly, the highest protein level expression of NR1 and NR2B subunits was also observed at P7 in both sides hippocampi. Although the protein expression of NR1 was significantly higher on the right side in all studied days, the NR2B was significantly higher in the right hippocampus only at P7. The analysis of optical density (OD) has shown a marked increase in the distribution pattern of the NR1 and NR2B subunits at P7 in all hippocampal subregions. In conclusion, there is a marked right-left asymmetry in the expression of NR1 and NR2B subunits in the developing rat hippocampus, which might be considered as a probable mechanism for the lateral differences in the structure and function of the hippocampus in rats.

Long-term exposure to electromagnetic radiation from mobile phones can cause considerable changes in the balance of Bax/Bcl2 mRNA expression in the hippocampus of mice.

The aim of the present study was the investigation of the effects of mobile phones at different daily exposure times on the hippocampal expression of two apoptotic genes. Forty-eight male BALB/c mice were randomly divided into six groups with 8 animals in each group. Four experimental groups were respectively exposed to electromagnetic waves for 0.5, 1, 2 and 4 hours twice a day for 30 consecutive days. One experimental group was radiated for 4 hours once a day, while the control group did not receive any radiation during the experiment. The expression of both Bax and Bcl2 mRNAs was upregulated in the mice exposed for one and two hours. Whilst the highest expressions were observed in the two-hours radiation in the exposed group, the expression of both studied genes was downregulated in animals with longer exposure to radiation in a duration-dependent manner. The highest ratio of Bax/Bcl2 expression was observed in the mice that received radiation for four hours twice a day. These results revealed that mobile phone radiation can cause considerable changes in the balance of Bax/Bcl2 mRNA expression in laboratory mice hippocampus.

A link between nanoparticles and Parkinson's disease. Which nanoparticles are most harmful?

Nowadays, different kinds of nanoparticles (NPs) are produced around the world and used in many fields and products. NPs can enter the body and aggregate in the various organs including brain. They can damage neurons, in particular dopaminergic neurons in the substantia nigra (SN) and striatal neurons which their lesion is associated with Parkinson's disease (PD). So, NPs can have a role in PD induction along with other agents and factors. PD is the second most common neurodegenerative disease in the world, and in patients, its symptoms progressively worsen day by day through different pathways including oxidative stress, neuroinflammation, mitochondrial dysfunction, α-synuclein increasing and aggregation, apoptosis and reduction of tyrosine hydroxylase positive cells. Unfortunately, there is no effective treatment for PD. So, prevention of this disease is very important. On the other hand, without having sufficient information about PD inducers, prevention of this disease would not be possible. Therefore, we need to have sufficient information about things we contact with them in daily life. Since, NPs are widely used in different products especially in consumer products, and they can enter to the brain easily, in this review the toxicity effects of metal and metal oxide NPs have been evaluated in molecular and cellular levels to determine potential of different kinds of NPs in development of PD.

Developmental regulation and lateralisation of the α7 and α4 subunits of nicotinic acetylcholine receptors in developing rat hippocampus.

The purpose of this study was to describe the distinct regional distribution patterns of expression of the α7 and α4 subunits of nicotinic acetylcholine receptors (nAChRs) and their left-right lateralisation in the rat hippocampus during the first 2 weeks of postnatal (P) development. Eighteen male pups were randomly divided into three groups: P0, P7, and P14. After removing the newborn brains, real-time polymerase chain reaction, western blot, and immunohistochemistry techniques were used to evaluate expression of the receptors. Results indicated that the expression profile of these receptors were time- and spatially dependent. A significant increase was observed in the distribution of α7 and α4 nAChR subunits in the developing rat hippocampus from P0 to P7 (p < .001); however, there was a significant decrease from P7 to P14 (p < .05). As a spatial effect, the highest optical density (OD) was observed in the CA3 and CA2 regions of the hippocampus, while the lowest OD was in the dentate gyrus. Moreover, the distribution of α7 and α4 nAChR subunits in the left hippocampus was significantly higher than their counterparts in the right (p < .05). From these data, the expression patterns of α7 and α4 nAChR subunits exhibited left-right asymmetry in the developing rat hippocampus.

Functional dopaminergic neurons derived from human chorionic mesenchymal stem cells ameliorate striatal atrophy and improve behavioral deficits in Parkinsonian rat model.

Human chorionic mesenchymal stem cells (HCMSCs) have been recognized as a desirable choice for cell therapy in neurological disorders such as Parkinson's disease (PD). Due to invaluable features of HCMSCs including their immunomodulatory and immunosuppressive properties, easily accessible and less differentiated compared to other types of MSCs, HCMSCs provide a great hope for regenerative medicine. Thus, the purpose of this study was to determine the in vitro and in vivo efficacy of HCMSCs-derived dopaminergic (DA) neuron-like cells with regard to PD. Initially, HCMSCs were isolated and underwent a 2-week DA differentiation, followed by in vitro assessments, using quantitative real-time polymerase chain reaction, immunocytochemistry, patch clamp recording, and high-performance liquid chromatography. In addition, the effects of implanted HCMSCs-derived DA neuron-like cells on the motor coordination along with stereological alterations in the striatum of rat models of PD were investigated. Our results showed that under neuronal induction, HCMSCs revealed neuron-like morphology, and expressed neuronal and DA-specific genes, together with DA release. Furthermore, transplantation of HCMSCs-derived DA neurons into the striatum of rat models of PD, augmented performance. Besides, it prevented reduction of striatal volume, dendritic length, and the total number of neurons, coupled with a diminished level of cleaved caspase-3. Altogether, these findings suggest that HCMSCs could be considered as an attractive strategy for cell-based therapies in PD.

Developmental regulation and lateralization of GABA receptors in the rat hippocampus.

GABA is the chief inhibitory neurotransmitter in the adult brain. However, in the developing brain it acts as an excitatory transmitter causing depolarization. Thereby, activates calcium-dependent processes that are crucial for brain development. Accordingly, GABA receptors have the great role in the brain development, especially in the area with persisting neurogenesis such as hippocampus. The present study investigated the development and lateralization of two important subunits of GABA receptors, GABAAα1 and GABAB1, in the developing rat hippocampus during the neurogenesis-active period, at the first two postnatal weeks. Real-time PCR, western blot and immunohistochemistry were used. We found that the mRNA and protein of these GABA receptor subunits have already been expressed at birth and significantly increased at postnatal day (P) 7, and also at P14. Also, regarding the optical densities of GABAAα1 and GABAB1 expressing hippocampal cells, we found a significant increase in the distribution pattern of these subunits in the all hippocampal subregions on day 14 after birth. The highest optical density of GABAAα1 was observed in the CA3, and GABAB1 in the CA2. Nevertheless, our results did not show a significant laterality differences in the expression of these subunits. Regarding the crucial role of GABA receptors in the hippocampus development; they probably have the same effects on development of the rat hippocampus on both sides.

Nigral injection of 6-hydroxydopamine induces changes in spatial arrangement of striatal neuron and glial cells.

In Parkinson's disease, nigral dopamine neurons are lost and the structure of the striatum is progressively degraded. These events lead to a substantial neuronal loss in the striatum, changing spatial pattern of the neurons and glial cells, and associated cellular connections. Therefore, the aim of this study was to develop a new insight into whether the Parkinson's disease causes a change in the spatial arrangement of the neurons and glial cells in the striatum. Nigral injection of 6-hydroxydopamine led to a significant reduction in the total number of the neurons, an increase in the number of striatal glial cells, and disruption in the spatial arrangement of glial and neuronal cells in the Parkinson's disease-induced group, compared to the control group. The data support the idea that in Parkinson's disease, the function of the striatum is disturbed by both the loss of neurons and an increase in the number of glial cells, culminating in the disordered spatial distribution of these cells.

Exposure to mephedrone during gestation increases the risk of stillbirth and induces hippocampal neurotoxicity in mice offspring.

In recent years, abuse of synthetic cathinones, in particular, mephedrone, has increased among young adults worldwide. The study aim is to investigate the effects of mephedrone exposure during the gestational period on mice offspring outcomes, focusing on hippocampal neurotoxicity. The pregnant mice received mephedrone (50 mg/kg, sc) on a regular schedule (once daily on all days, from day 5 to 18 of gestation) or repeated schedule (thrice daily on day 5, 6, 11, 12, 17, and 18 of gestation) to simulate regular or recreational use of mephedrone, respectively. Results showed that the percentage of weight gain in pregnant mice was significantly lower in both regular and repeated schedule mephedrone groups (p < 0.01). Also, mephedrone significantly reduced the number and weight of delivered pups and increased the rate of stillbirth (p < 0.05). Immunohistochemistry and TUNEL assay showed an inhibition of cell proliferation (p < 0.05) and an increase of apoptosis (p < 0.05) in the hippocampus of delivered pups of the repeated schedule mephedrone group. This apoptotic effect was associated with enhanced expression of the pro-apoptotic Bax gene (p < 0.05) and reduction of expression of the anti-apoptotic Bcl-2 gene (p < 0.05) as evaluated by real-time PCR. The Morris water maze showed an impairment of spatial learning (p < 0.05) and reference memory (p < 0.01) in offspring born from litters exposed to mephedrone (repeated schedule). In conclusion, the present study has shown that regular and repeated exposure to mephedrone during the gestational period increases the risk of low birth weight and stillbirth. Also, repeated use of mephedrone impairs learning and memory processes through hippocampal damage.

Evaluation of bax, bcl-2, p21 and p53 genes expression variations on cerebellum of BALB/c mice before and after birth under mobile phone radiation exposure.

OBJECTIVES: The increasing rate of over using cell phones has been considerable in youths and pregnant women. We examined the effect of mobile phones radiation on genes expression variation on cerebellum of BALB/c mice before and after of the birth. MATERIALS AND METHODS: In this study, a mobile phone jammer, which is an instrument to prevent receiving signals between cellular phones and base transceiver stations (two frequencies 900 and 1800 MHz) for exposure was used and twelve pregnant mice (BALB/c) divided into two groups (n=6), first group irradiated in pregnancy period (19th day), the second group did not irradiate in pregnancy period. After childbirth, offspring were classified into four groups (n=4): Group1: control, Group 2: B1 (Irradiated after birth), Group 3: B2 (Irradiated in pregnancy period and after birth), Group 4: B3 (Irradiated in pregnancy period). When maturity was completed (8-10 weeks old), mice were dissected and cerebellum was isolated. The expression level of bax, bcl-2, p21 and p53 genes examined by real-time reverse transcription polymerase chain reaction (Real-Time RT- PCR). RESULTS: The data showed that mobile phone radio waves were ineffective on the expression level of bcl-2 and p53 genes) P>0.05(. Also gene expression level of bax decreased and gene expression level of p21 increased comparing to the control group (P<0.05). CONCLUSION: From the obtained data it could be concluded that the mobile phone radiations did not induce apoptosis in cells of the cerebellum and the injured cells can be repaired by cell cycle arrest.

Maternal exposure to titanium dioxide nanoparticles during pregnancy and lactation alters offspring hippocampal mRNA BAX and Bcl-2 levels, induces apoptosis and decreases neurogenesis.

INTRODUCTION: The usage of Titanium dioxide nanoparticles (TiO2-NPs) covers a vast area in different fields ranging from cosmetics and food to the production of drugs. Maternal exposure to TiO2-NPs during developmental period has been associated with hippocampal injury and with a decrease in learning and memory status of the offspring. However, little is known about its injury mechanism. This paper describes the in vivo neurotoxic effects of TiO2-NPs on rat offspring hippocampus during developmental period. MATERIAL AND METHODS: Pregnant and lactating Wistar rats received intragastric TiO2-NPs (100mg/kg body weight) daily from gestational day (GD) 2 to (GD) 21 and postnatal day (PD) 2 to (PD) 21 respectively. Animals in the control groups received an equal volume of distilled water via gavage. At the end of the treatment process, offspring were deeply anesthetized and sacrificed. Then brains of each group were collected and sections of the rat offspring's brains were stained using TUNEL staining (for detection of apoptotic cells) and immunostaining (for neurogenesis). Moreover, the right hippocampus (n=6 per each group) were removed from the right hemisphere for evaluating the expression of Bax and Bcl-2 level. RESULTS: Results of histopatological examination by TUNEL staining showed that maternal exposure to TiO2-NPs during pregnancy and lactation periods increased apoptotic cells significantly (P<0.01) in the offspring hippocampus. The immunolabeling of double cortin (DCX) protein as neurogenesis marker also showed that TiO2-NPs reduced neurogenesis in the hippocampus of the offspring (P<0.05). Moreover, in comparison with the control group, the mRNA levels of Bax and Bcl-2 in the TiO2-NPs group significantly increased and decreased, respectively (P<0.01). CONCLUSION: These findings provide strong evidence that maternal exposure to TiO2-NPs significantly impact hippocampal neurogenesis and apoptosis in the offspring. The potential impact of nanoparticle exposure for millions of pregnant mothers and their offspring across the world is potentially devastating.