Offspring Of Control Rats Research Articles

Prenatal Immune Challenge Differentiates the Effect of Aripiprazole and Risperidone on CD200-CD200R and CX3CL1-CX3CR1 Dyads and Microglial Polarization: A Study in Organotypic Cortical Cultures.

Microglia are the primary innate immune cells of the central nervous system and extensively contribute to brain homeostasis. Dysfunctional or excessive activity of microglia may be associated with several neuropsychiatric disorders, including schizophrenia. Therefore, we examined whether aripiprazole and risperidone could influence the expression of the Cd200-Cd200r and Cx3cl1-Cx3cr1 axes, which are crucial for the regulation of microglial activity and interactions of these cells with neurons. Additionally, we evaluated the impact of these drugs on microglial pro- and anti-inflammatory markers (Cd40, Il-1β, Il-6, Cebpb, Cd206, Arg1, Il-10 and Tgf-β) and cytokine release (IL-6, IL-10). The research was executed in organotypic cortical cultures (OCCs) prepared from the offspring of control rats (control OCCs) or those exposed to maternal immune activation (MIA OCCs), which allows for the exploration of schizophrenia-like disturbances in animals. All experiments were performed under basal conditions and after additional stimulation with lipopolysaccharide (LPS), following the "two-hit" hypothesis of schizophrenia. We found that MIA diminished the mRNA level of Cd200r and affected the OCCs' response to additional LPS exposure in terms of this parameter. LPS downregulated the Cx3cr1 expression and profoundly changed the mRNA levels of pro- and anti-inflammatory microglial markers in both types of OCCs. Risperidone increased Cd200 expression in MIA OCCs, while aripiprazole treatment elevated the gene levels of the Cx3cl1-Cx3cr1 dyad in control OCCs. The antipsychotics limited the LPS-generated increase in the expression of proinflammatory factors (Il-1β and Il-6) and enhanced the mRNA levels of anti-inflammatory components (Cd206 and Tgf-β) of microglial polarization, mostly in the absence of the MIA procedure. Finally, we observed a more pronounced modulating impact of aripiprazole on the expression of pro- and anti-inflammatory cytokines when compared to risperidone in MIA OCCs. In conclusion, our data suggest that MIA might influence microglial activation and crosstalk of microglial cells with neurons, whereas aripiprazole and risperidone could beneficially affect these changes in OCCs.

A pilot exploring the impact of paternal puberty blocking on offspring voluntary wheel running

Previous work from our lab has shown puberty blocking treatment in young female rats followed by discontinued use (or detransition) leads to decreased voluntary wheel running activity in their offspring. The purpose of the present study was to determine if puberty blocking and detransition in young male rats affects offspring voluntary wheel running activity. We hypothesized that offspring of previously puberty blocked male rats will have lower wheel running activity than offspring of control rats. Four week old, male Sprague-Dawley rats received either 100 μg of the gonadotropin releasing hormone agonist triptorelin daily as a puberty blocker or 0.9% saline daily as a control. At the end of the 4 week treatment period, injections ceased, and each male rat was paired with an age-matched female rat for breeding. The breeding period lasted approximately 8 weeks and resulted in pregnancy of each paired female. At 6 weeks of age, a portion of the offspring were randomly assigned to the following voluntary wheel running groups: male offspring of previously puberty blocked males (M-PBO, n=2), female offspring of previously puberty blocked males (F-PBO, n=2), male offspring of control males (M-CON, n=5), and female offspring of control males (F-CON, n=5). Offspring were housed in cages outfitted with voluntary running wheels, received food and water ad libitum, and were maintained on a12:12 hour light:dark cycle. Voluntary wheel running activity was monitored for 8 weeks, and between-group comparisons were made via Welch’s t-test. Voluntary wheel running activity is presented as number of wheel running rotations, and data are shown as mean ± standard error. For total wheel running activity over 8 weeks, M-PBO had significantly lower voluntary wheel running activity than M-CON (107,453 ± 50,683 rotations vs. 456,011 ± 62,970 rotations, respectively, p=0.0122). There were no differences observed, however, between F-PBO and F-CON for total 8-week wheel running activity (376,582 ± 1,847 rotations vs. 472,271 ± 116,017 rotations, p=0.4559). Additionally, M-PBO ran significantly less than M-CON in weeks 1, 2, 3, 6, 7, and 8 (Week 1: 5,606 ± 225 rotations vs. 17,824 ± 2,544 rotations, p=0.0084; Week 2: 11,537 ± 3,129 rotations vs. 51,882 ± 6,494 rotations, p=0.0025; Week 3: 10,157 ± 2,639 rotations vs. 79,257 ± 5,842 rotations, p=0.0001; Week 6: 15,816 ± 7,865 rotations vs. 64,425 ± 11,755 rotations, p=0.0207; Week 7: 14,068 ± 6,999 rotations vs. 58,112 ± 9,781 rotations, p=0.0178; Week 8: 13,234 ± 6351 rotations vs. 67,349 ± 16,142 rotations, p=0.0272, respectively). No differences were observed in weekly wheel running activity between F-PBO and F-CON. Based on the observed voluntary wheel running activity, puberty blocking male rats prior to breeding negatively impacted physical activity of male offspring but not female offspring. This is contrary to our previous work showing that puberty blocking treatment followed by detransition in female rats prior to breeding negatively impacted physical activity of both male and female offspring. Our hypothesis was therefore partially supported as M-PBO had significantly less wheel running activity than M-CON, but F-PBO and F-CON had similar wheel running activity. Supported by a University of Northern Colorado Provost's Seed Grant awarded to DSH. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Chronic inhibition of astrocytic aquaporin-4 induces autistic-like behavior in control rat offspring similar to maternal exposure to valproic acid

Social communication and interaction deficits, memory impairment, and anxiety-like behavior are characterized in many people identified with autism spectrum disorder (ASD). A thorough understanding of the specific aspects that contribute to the deficiencies associated with ASD can aid research into the etiology of the disorder while also providing targets for more effective intervention. As part of the ASD pathophysiology, alterations in synaptogenesis and abnormal network connections were seen in high-order brain areas, which control social behavior and communication. The early emergence of microglia during nervous system development may contribute to synaptic dysfunction and the pathobiology of ASD. Since aquaporin-4 (AQP4) appears to be required for the basic procedures of synapse activation, certain behavioral and cognitive impairments as well as disturbance in water homeostasis might likely arise from AQP4 deficiency. Here, through the measurement of the water content of the hippocampus and behavioral experiments we aim to explore the contribution of astrocytic AQP4 to the autism-like behavior induced by prenatal valproic acid (VPA) exposure and whether inhibition of AQP4 per se can induce autistic-like behavior in control rats.Microinjection of TGN-020 (10 µM, i.c.v), a specific AQP4 inhibitor, for 7 successive days before behavioral tasks from postnatal day 28 to 35 revealed that inhibition of AQP4 in the control offspring caused lower social interaction and locomotor activity, higher anxiety, and decreased ability to recognize novel objects, very similar to the behavioral changes observed in offspring prenatally exposed to VPA. However, VPA-exposed offspring treated with TGN-020, showed no further remarkable behavioral impairments than those detected in the autistic-like rats. Furthermore, both control offspring treated with TGN-020 and offspring exposed to VPA had a considerable accumulation of water in their hippocampi. But AQP4 inhibition did not affect the water status of the autistic-like rats.The findings of this study revealed that control offspring exhibited similar hippocampal water retention and behavioral impairments that were observed in maternal VPA-exposed offspring following inhibition of astrocytic AQP4, whereas, in autistic-like rats, it did not produce any significant change in water content and behaviors. Findings suggest that AQP4 deficiency could be associated with autistic disorder and may be a potential pharmaceutical target for treating autism in the future.

Insights into the Potential Impact of Quetiapine on the Microglial Trajectory and Inflammatory Response in Organotypic Cortical Cultures Derived from Rat Offspring.

Atypical antipsychotics currently constitute the first-line medication for schizophrenia, with quetiapine being one of the most commonly prescribed representatives of the group. Along with its specific affinity for multiple receptors, this compound exerts other biological characteristics, among which anti-inflammatory effects are strongly suggested. Simultaneously, published data indicated that inflammation and microglial activation could be diminished by stimulation of the CD200 receptor (CD200R), which takes place by binding to its ligand (CD200) or soluble CD200 fusion protein (CD200Fc). Therefore, in the present study, we sought to evaluate whether quetiapine could affect certain aspects of microglial activity, including the CD200-CD200R and CX3CL1-CX3CR1 axes, which are involved in the regulation of neuron-microglia interactions, as well as the expression of selected markers of the pro- and anti-inflammatory profile of microglia (Cd40, Il-1β, Il-6, Cebpb, Cd206, Arg1, Il-10 and Tgf-β). Concurrently, we examined the impact of quetiapine and CD200Fc on the IL-6 and IL-10 protein levels. The abovementioned aspects were investigated in organotypic cortical cultures (OCCs) prepared from the offspring of control rats (control OCCs) or those subjected to maternal immune activation (MIA OCCs), which is a widely implemented approach to explore schizophrenia-like disturbances in animals. The experiments were performed under basal conditions and after additional exposure to the bacterial endotoxin lipopolysaccharide (LPS), according to the "two-hit" hypothesis of schizophrenia. The results of our research revealed differences between control and MIA OCCs under basal conditions and in response to treatment with LPS in terms of lactate dehydrogenase and nitric oxide release as well as Cd200r, Il-1β, Il-6 and Cd206 expression. The additional stimulation with the bacterial endotoxin resulted in a notable change in the mRNA levels of pro- and anti-inflammatory microglial markers in both types of OCCs. Quetiapine diminished the influence of LPS on Il-1β, Il-6, Cebpb and Arg1 expression in control OCCs as well as on IL-6 and IL-10 levels in MIA OCCs. Moreover, CD200Fc reduced the impact of the bacterial endotoxin on IL-6 production in MIA OCCs. Thus, our results demonstrated that quetiapine, as well as the stimulation of CD200R by CD200Fc, beneficially affected LPS-induced neuroimmunological changes, including microglia-related activation.

Sex-dependent effects of early life stress on reinforcement learning and limbic cortico-striatal functional connectivity

Major depressive disorder (MDD) is a stress-related condition hypothesized to involve aberrant reinforcement learning (RL) with positive and negative stimuli. The present study investigated whether repeated early maternal separation (REMS) stress, a procedure widely recognized to cause depression-like behaviour, affects how subjects learn from positive and negative feedback. The REMS procedure was implemented by separating male and female rats from their dam for 6 h each day from post-natal day 5–19. Control rat offspring were left undisturbed during this period. Rats were tested as adults for behavioral flexibility and feedback sensitivity on a probabilistic reversal learning task. A computational approach based on RL theory was used to derive latent behavioral variables related to reward learning and flexibility. To assess underlying brain substrates, a seed-based functional MRI connectivity analysis was applied both before and after an additional adulthood stressor in control and REMS rats. Female but not male rats exposed to REMS stress showed increased response ‘stickiness’ (repeated responses regardless of reward outcome). Following repeated adulthood stress, reduced functional connectivity from the basolateral amygdala (BLA) to the dorsolateral striatum (DLS), cingulate cortex (Cg), and anterior insula (AI) cortex was observed in females. By contrast, control male rats exposed to the second stressor showed impaired learning from negative feedback (i.e., non-reward) and reduced functional connectivity from the BLA to the DLS and AI compared to maternally separated males. RL in male rats exposed to REMS was unaffected. The fMRI data further revealed that connectivity between the mOFC and other prefrontal cortical and subcortical structures was positively correlated with response ‘stickiness’. These findings reveal differences in how females and males respond to early life adversity and subsequent stress. These effects may be mediated by functional divergence in resting-state connectivity between the basolateral amygdala and fronto-striatal brain regions.

Gestational diabetes influences retinal Muller cells in rat's offspring.

Objective(s):The Muller cell is the principal glial cell of the vertebrate retina. The expression of Glial fibrillary acidic protein (GFAP) in the Muller cells was used as a cellular marker for retinal damage. This study was done to evaluate the effect of gestational diabetes on retinal Muller cells in rat’s offspring.Materials and Methods:In this experimental study, 12 Wistar rat dams were randomly allocated in control and diabetic groups. Gestational diabetes was induced by 40 mg/kg/body weight of streptozotocin at the first day of gestation, intraperitoneally. Dams in control group received an equivalent volume normal saline. Eye of six offspring of each group were removed at postnatal day 28 (P28). The histopathological changes in retina were examined through H&E staining and ultrastructure transmission electron microscopy (TEM). The expression of GFAP was examined using Immunohisto-chemical staining of GFAP in Muller cells. Photographs of retina were taken using Olympus BX51 microscope and a digital camera DP12 and EM LEO906; Zeiss, Germany.Results:In the control rat’s offspring, GFAP expression was not significant in Muller cells. According to the optical microscope images, GFAP expression was observed in the processes of the Muller cell in the inner plexiform layer of retina in offspring of diabetic mothers. In TEM technique, nuclear fragmentation and apoptotic bodies were observed in Muller cell of diabetic offspring.Conclusion:This study showed that the uncontrolled gestational diabetes can increase GFAP expression in Muller cells and retinal thickness of retinal layer in rat offspring’s, therefore uncontrolled gestational can damage the Muller cells.

MicroRNA-29a induces insulin resistance by targeting PPARδ in skeletal muscle cells.

Intrauterine growth retardation (IUGR) induces metabolic syndrome, which is often characterized by insulin resistance (IR), in adults. Previous research has shown that microRNAs (miRNAs or miRs) play a role in the target genes involved in this process, but the mechanisms remain unclear. In the present study, we examined miRNA profiles using samples of skeletal muscles from both IUGR and control rat offspring whose mothers were fed either a protein-restricted diet or a diet which involved normal amounts of protein during pregnancy, respectively. miR-29a was found to be upregulated in the skeletal muscles of IUGR offspring. The luciferase reporter assay confirmed the direct interaction between miR-29a and peroxisome proliferator-activated receptor δ (PPARδ). Overexpression of miR-29a in the skeletal muscle cell line C2C12 suppressed the expression of its target gene PPARδ, which, in turn, influenced the expression of its coactivator, peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). Thus, PPARδ/PGC-1α-dependent signals together reduced insulin-dependent glucose uptake and adenosine triphosphate (ATP) production. Overexpression of miR-29a also caused a decrease in levels of glucose transporter 4 (GLUT4), the most important glucose transporter in skeletal muscle, which partially induced a decrease insulin-dependent glucose uptake. These findings provide evidence for a novel micro-RNA-mediated mechanism of PPARδ regulation, and we also noted the IR-promoting actions of miR-29a in skeletal muscles of IUGR.

Maternal periodontitis decreases plasma membrane GLUT4 content in skeletal muscle of adult offspring

AimsThe fetal programming hypothesis suggests that intrauterine stimuli can induce metabolic changes in offspring, increasing the disease risk in adulthood. Periodontal disease may enhance serum cytokine levels. Cytokines such as tumor necrosis factor-alpha (TNF-α) have been associated with reduced glucose transporter type 4 (GLUT4) expression, decreased protein kinase B (Akt) phosphorylation, and insulin resistance. This study aimed to evaluate GLUT4 content, and Akt serine phosphorylation status in the gastrocnemius skeletal muscle (GSM), glycemia, insulinemia and change in body weight in offspring of rats with periodontal disease. Main methodsFemale Wistar rats were distributed into a control group (CN) and an experimental periodontal disease group (PD), in which a ligature was placed around the mandibular first molars. Seven days after ligature placement, both groups were mated with normal male rats. The ligatures remained throughout pregnancy until weaning, after which the male offspring were distributed into groups: CN-o, control rat offspring; and PD-o, periodontal disease rat offspring. The body weight from 0 to 75days of age was measured. At 75days, the glycemia, insulinemia, TNF-α levels, Akt serine phosphorylation, and GLUT4 content in the GSM were measured in the offspring. Key findingsThe PD-o group showed a low birth weight (LBW), unchanged glycemia, increased insulinemia, insulin resistance, increased TNF-α levels, decreased Akt serine phosphorylation status, and reduced GLUT4 content in the plasma membrane and translocation index after insulin stimulation. SignificanceMaternal periodontal disease causes LBW, insulin resistance, and alterations in the final stage of insulin signaling in the GSM of adult offspring.

Perinatal citalopram does not prevent the effect of prenatal stress on anxiety, depressive-like behaviour and serotonergic transmission in adult rat offspring.

It is still not clear whether the selective serotonin reuptake inhibitors frequently prescribed to depressed pregnant women improve the behavioural outcome in their children. The current study investigated whether administration of citalopram to pregnant rats could prevent anxiety and depressive-like behaviour induced by gestational stress in their offspring, and restore the expression of serotonin 1A autoreceptors in GABAergic interneurons in the medial prefrontal cortex and dorsal raphe nuclei in males, and of corticotropin-releasing factor type 2 receptors in GABAergic interneurons in the dorsal raphe nuclei in females. Activation of these receptors modulates serotonergic transmission to target areas and is reduced in a sex-dependent manner by prenatal stress. Citalopram (10mg/kg/day), administered orally from day 7 of gestation until 21days postpartum, prevented the increase in anxiety in stressed mothers but did not reduce anxiety and depressive-like behaviour in their offspring and even induced depressive-like behaviour in the offspring of control mothers. Citalopram failed to restore the reduction in the expression of serotonin 1A autoreceptors in the prefrontal cortex of males and in corticotropin-releasing factor type 2 receptors in the dorsal raphe nuclei of females induced by prenatal stress. Prenatal citalopram did not prevent the behavioural changes or reduction in serotonergic transmission to target areas induced by prenatal stress. It had adverse behavioural effects in the offspring of control rats, which, together with the lack of any change in prenatally-stressed rats, may be due to inhibition of the foetal serotonin transporter thereby preventing normal development of the serotonin system.

Neurobehavioural effects of prenatal sodium valproate exposure in rat offspring

Pregnant rats were administered sodium valproate (12.5, 25 and 50 mg/kg/day) orally once daily during the gestation days 13 to 20. Maternal sodium valproate treatment produced a dose dependent significant reduction in litter size at birth and reduced body growth during postnatal days. Sodium valproate treatment had no significant effect on maternal weight gain during pregnancy and pups mortality during postnatal period. The pups born were subjected to open-field exploratory behaviour and elevated plus maze tests of anxiety at 8 and 9 weeks of age. Prenatal sodium valproate treatment (12.5, 25 and 50 mg/kg/day) induced significant increase in open-field ambulation, rearings and self-grooming in rat offspring. Prenatal sodium valproate treated rat offspring displayed significantly increased anxiogenic behaviour on elevated plus maze (spent less time on open arms, more time on enclosed arms and made fewer number of entries on open arms) comparison to control rat offspring. The results suggest that prenatal sodium valproate exposure induces neurobehavioural toxicity and indicate persistent behavioural alterations in the rat offspring.

Effect of Prenatal Exposure of Clobazam on Anxiety Parameters in Rat Offspring

Behavioural teratological effects of prenatal clobazam exposure were investigated on anxiety parameters in rats. Pregnant rats were administered clobazam (0.5, 1, 2 and 5 mg/kg/day) orally once a day during the gestation days 13 to 20. The pups born were subjected to open-field exploratory behaviour, elevated plus maze and elevated zero maze tests at 8 weeks of age. The results indicated that prenatal clobazam treatment (0.5, 1, 2 and 5 mg/kg/day) induced significant increase in open-field ambulation, rearings and self-grooming in rat offspring. Rat offspring treated with different doses of clobazam during the prenatal period displayed dose dependent significant increase in anxiogenic behaviour patterns on elevated plus maze and elevated zero maze in comparison to control rat offspring. The findings highlight that prenatal clobazam treatment induced persistent behavioural alterations on anxiety parameters in the rat offspring.

Effects of maternal fluoxetine treatment on behavioural despair and learned helplessness parameters of depression in the rat progeny

Behavioural teratological effects of prenatal fluoxetine exposure were investigated on behavioural despair and learned helplessness parameters of depression in rats. Pregnant rats were administered fluoxetine (5 and 10 mg/kg/day) orally once a day during the gestation days 13 to 20. The pups born were subjected to forced swimming test of behavioural despair and learned helplessness test at 8 weeks of age. The results indicated that prenatal fluoxetine treatment (5 and 10 mg/kg/day) induced significant increase in time of immobility in forced swimming test and number of escape failures in learned helplessness test in rat offspring. Rat offspring treated with 5 and 10 mg/kg fluoxetine during the prenatal period displayed dose dependent significant increase in time of immobility in behavioural despair test and number of escape failures in learned helplessness test in comparison to control rat offspring. The findings highlight that prenatal fluoxetine treatment caused depressive like behavioural alterations in the rat offspring.

English

Lead (Pb) is a heavy metal environmental pollutant and toxicant. The present study investigated dose-related effects of maternal Pb exposure on pregnancy outcome. Wistar albino rats were gavaged with Pb nitrate (4 or 8 mg/kg) or vehicle daily from gestation day 0 until delivery. Length of pregnancy was noted. Number, birth weight and physical characteristics of pups were registered. Neonatal mortality was also recorded between days 1 to 15 post-delivery. Lead treatment significantly (p < 0.05) inhibited maternal body weight gain and caused abortion of pregnancy dose-dependently (4 mg/kg: 67.7%, 8 mg/kg: 100%). Besides, all occurring births in 4 mg/kg Pb-exposed rats were preterm (p = 0.0023) with morphological abnormalities in the head and limbs, and about 33% were still births. Also, average number and birth weight of Pb-exposed rats offspring were significantly (p < 0.0001) lower compared to controls. Furthermore, while body weights of offspring of control rats increased significantly (p < 0.0001) over time, those of Pb-exposed rats decreased significantly (p = 0.0077). Neonatal survival was 0% in Pb treated rats and 100% in control. The results demonstrate that maternal Pb exposure adversely and dose-dependently affects pregnancy outcome. Key words: Developmental toxicity, gestation, heavy metals, lead, reproductive toxicity, resorption.

Effect of age and COX‐2‐derived prostanoids on the progression of adult vascular dysfunction in the offspring of diabetic rats

The present study was designed to determine how diabetes in pregnancy affects vascular function in their offspring, the influence of age and whether COX activation is involved in this effect. Relaxation responses to ACh were analysed in mesenteric resistance arteries from the offspring of control rats (O-CR) and those of diabetic rats (O-DR) at 3, 6 and 12 months of age. TxB₂, PGE₂ and PGF(2α) release were determined by enzyme immunoassay. COX-1 and COX-2 expression were measured by Western blot analysis. O-DR developed hypertension from 6 months of age compared with O-CR. In O-DR, relaxation responses to ACh were impaired in all ages studied and were restored by COX-2 inhibition. TP receptor blockade (SQ29548) restored ACh relaxation in arteries from 3-month-old O-DR while TP and EP receptor blockade (SQ29548 + AH6809) was required to restore it in 6-month-old O-DR. In 12-month-old O-DR, ACh relaxation was restored when TP, EP and FP receptors were blocked (SQ29548 + AH6809 + AL8810). ACh-stimulated TxB₂ was higher in all O-DR. ACh-stimulated PGE₂ release was increased in arteries from 6- and 12-month-old O-DR, whereas PGF(2α) was increased only in 12-month-old O-DR. COX-2, but not COX-1, expression was higher in O-DR than O-CR. The results indicate an age-dependent up-regulation of COX-2 coupled to an enhanced formation of vasoconstrictor prostanoids in resistance arteries from O-DR. This effect plays a key role in the pathogenesis of endothelial dysfunction, which in turn could contribute to the progression of vascular dysfunction in these rats.

Intrauterine growth restriction promotes vascular remodelling following carotid artery ligation in rats

Epidemiological studies revealed an association between IUGR (intrauterine growth restriction) and an increased risk of developing CVDs (cardiovascular diseases), such as atherosclerosis or hypertension, in later life. Whether or not IUGR contributes to the development of atherosclerotic lesions, however, is unclear. We tested the hypothesis that IUGR aggravates experimentally induced vascular remodelling. IUGR was induced in rats by maternal protein restriction during pregnancy (8% protein diet). To detect possible differences in the development of vascular injury, a model of carotid artery ligation to induce vascular remodelling was applied in 8-week-old intrauterine-growth-restricted and control rat offspring. Histological and immunohistochemical analyses were performed in the ligated and non-ligated carotid arteries 8 weeks after ligation. IUGR alone neither caused overt histological changes nor significant dedifferentiation of VSMCs (vascular smooth muscle cells). After carotid artery ligation, however, neointima formation, media thickness and media/lumen ratio were significantly increased in rats after IUGR compared with controls. Moreover, dedifferentiation of VSMCs and collagen deposition in the media were more prominent in ligated carotids from rats after IUGR compared with ligated carotids from control rats. We conclude that IUGR aggravates atherosclerotic vascular remodelling induced by a second injury later in life.

Adipocyte pyruvate dehydrogenase kinase 4 expression is associated with augmented PPARγ upregulation in early-life programming of later obesity

We studied adipocytes from 8-week-old control rat offspring (CON) or rat offspring subjected to maternal low (8%) protein (MLP) feeding during pregnancy/lactation, a procedure predisposing to obesity. Acute exposure to isoproterenol or adenosine enhanced PDK4 and PPARγ mRNA gene expression in CON and MLP adipocytes. Enhanced adipocyte Pdk4 expression correlated with increased PPARγ expression. Higher levels of PDK4 and PPARγ were observed in MLP adipocytes. SCD1 is a PPARγ target. Isoproterenol enhanced adipocyte PDK4 and SCD1 gene expression in parallel. This could reflect augmented PPARγ expression together with enhanced lipolytic stimulation to supply endogenous PPARγ ligands, allowing enhanced adipocyte PDK4 and SCD1 expression via PPARγ activation. In contrast, the effect of adenosine to increase PDK4 expression is independent of stimulation of lipolysis and, as SCD1 expression was unaffected by adenosine, unlikely to reflect PPARγ activation. Increased adipocyte expression of both PDK4 and SCD1 in the MLP model could participate as components of a “thrifty” phenotype, favouring the development of obesity.

Prenatal stress diminishes gender differences in behavior and in expression of hippocampal synaptic genes and proteins in rats

The study determined whether there were gender differences in the expression of hippocampal genes in adult rats in association with dissimilarity in their behavior, and how these were affected by prenatal stress. Pregnant Wistar rats were subjected to varied stress once daily on days 14-20 of gestation. Adult female offspring of control rats showed significantly less anxiogenic behavior in the elevated plus maze and better discrimination between a novel and familiar object than males in the object recognition test. These gender differences in behavior were markedly attenuated by prenatal stress. Using Affymetrix DNA chip technology on hippocampal extracts prepared from littermates of the offspring used for behavioral tests, we found that 1,680 genes were differentially expressed in control males and females. The gender difference in gene expression was decreased to 11% (191 genes) by prenatal stress. In both sexes, processes like the translational machinery, mitochondrial activity, and cation transport were downregulated compared to controls, but there was a greater suppression of genes involved in vesicle trafficking, regulation of synaptic plasticity, and neurogenesis in females than in males. This was compensated by a higher expression of other components of vesicle trafficking, microtubule-based processes, and neurite development. Prenatal stress decreased the expression of 19 Rab proteins in females and five Rabs in males, but a compensatory increase of Rab partner proteins and effectors only occurred in females. Exposure to stress decreased the expression of synaptic proteins, synaptophysin, and synaptopodin in prenatally stressed males and females and increased those of PSD-95 and NR1 subunit of the N-methyl-D-aspartic acid (NMDA) glutamate receptor only in females. The study provides an unbiased view of key genes and proteins that act as gender dependent molecular sensors. The disruption of their expression by adverse early life stress may explain the alterations that occur in behavior.

Effect of prenatal phenytoin administration on brain tryptophan metabolism of rat offspring during the preweaning period.

Serum 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) concentrations in control rat offspring increased progressively during the preweaning period reaching adult values by day 21. It has been shown the prenatal phenytoin administration (100 mg kg-1 orally, days 7-19 of pregnancy) increased serum tryptophan and brain tryptophan, 5-HT and 5-HIAA of rat offspring at 3 days of age but not at 4, 15 or 21 days of age. The effect of prenatal phenytoin administration on the offspring at 3 days of age was not observed when these pups were cross-fostered to control mothers at 2 days of age suggesting that the alteration in rain tryptophan metabolism during the development of tryptaminergic neurons in rat offspring, as a result of prenatal phenytoin administration is mediated through changes in lactation or nursing ability of the mothers. It is important that such non-specific factors are controlled when studying the effect of prenatally administered drugs on neonatal brain transmitter concentrations.

Influence of Gamma Irradiation on DNA Methylation in Liver of Male Rats and their Offspring

In the present work, the influence of gamma radiation (3 Gy) on DNA methylation in slowly proliferating liver tissue of adult male rats and their offspring was studied. Total methylation of DNA was determined on the basis of presence of 5-methylcytosine at the inner cytosine of the C-C-G-G sequence by using restriction enzymes, endonuclease Msp I and its isoschisomer Hpa II. It was found that in the liver of control animals, molecular weight distribution of both Msp I and Hpa II digestion products of DNA and the level of DNA methylation were influenced by age mainly between the 3rd and the 7th days of life. At this time, significant difference was found especially in products of cleavage with enzyme Msp I, where an increase in DNA fragments of medium molecular weight (1 - 7 kb) occurred. The changes in the molecular weight distribution of DNA digestion products in the offspring of control rats were accompanied by an increase in the level of total DNA methylation from 29.8% to 67%. In the offspring of irradiated males, the level of DNA methylation was higher in comparison with the offspring of non-irradiated control males, especially on the 3rd day after birth. We suppose that this finding is conjoined with a transgeneration transfer of radiation-induced genome damage.

Streptozotocin diabetes in the pregnant rat induces cardiovascular dysfunction in adult offspring.

Severe diabetes in pregnant rats produces persistent metabolic consequences in adult offspring. This study investigated whether diabetes in pregnant rats could also lead to cardiovascular abnormalities in the adult offspring. Blood pressure, heart rate and in vitro vascular reactivity of small arteries were evaluated in female adult offspring of control rats and of rats rendered diabetic with streptozotocin. Rise in blood pressures were similar in both groups of offspring but heart rate was lower in the diabetic offspring (p < 0.05). The rise in blood pressure associated with infusion of a nitric oxide synthase inhibitor was similar in both groups, but the associated decrease in heart rate was more pronounced in diabetic offspring (p < 0.01). Small mesenteric arteries from this group showed enhanced sensitivity to noradrenaline (p < 0.05) and abnormal endothelium-dependent relaxation to acetylcholine (p < 0.01) and bradykinin (p < 0.05). Reduction in acetylcholine induced relaxation, reflected reduced synthesis of nitric oxide or a cyclooxygenase product and was not attributable to an endothelium-derived hyperpolarizing factor. Sensitivity to exogenous nitric oxide was normal. A subgroup of pups born to diabetic dams were suckled by control maternal dams and a subgroup of those born to controls by diabetic dams. Suckling was an important determinant of impaired growth; offspring of diabetic rats suckled by their own mother and those of control rats by diabetic dams showed impaired growth rates whereas growth of offspring of diabetic rats suckled by control dams paralleled those of control rats suckled by their own mother.