Genistein prevents the decrease in ganglioside levels induced by amyloid-beta in the frontal cortex of rats.

OBJECTIVES: In this study, an in vivo model of Aß toxicity was used to investigate the effects of this peptide and the treatment with genistein on the lipid composition (gangliosides, phospholipids and cholesterol) in the frontal cortex of rats. METHODS: Male Wistar rats received bilateral intracerebroventricular infusions of Aß1-42 (2 nmol) and genistein 10 mg/kg orally for 10 days. Frontal cortex was homogenized with chloroform:methanol for lipid extraction and ganglioside, phospholipid and cholesterol levels were evaluated. RESULTS: The Aß-infused animals showed a significant decrease in ganglioside concentration and relative reduction of GD1b and GQ1b species. Treatment with genistein prevented the decrease in ganglioside levels. Phospholipid and cholesterol contents did not show significant differences. DISCUSSION: Considering the roles of gangliosides on neuronal function, findings described here can contribute to the knowledge of the potential neuroprotective mechanisms of genistein against Aß-induced alterations in the frontal cortex of rats and provide a novel view in the multifaceted scenario associated with its beneficial effects.

Influence of gestational exercise practice and litter size reduction on maternal care.

Mother-pup interactions are extremely important to offspring survival and growth. The goal of this study was to evaluate the influence of prenatal and neonatal interventions on maternal care, analyzing the effect of maternal exercise, as a healthy intervention, and also the litter size reduction, a model that has been widely used to study early overfeeding in rats. Female Wistar rats were divided into 1) sedentary, and 2) swimming exercise for four weeks, starting one week before mating (5 days/week, 30 min/session). One day after birth, the litter was culled to 8 pups (normal) or 3 pups (small) per dam, yielding control and overfed subgroups for each maternal group, respectively. From postnatal days 2-9 the litter was observed 5 periods a day, to evaluate maternal behavior. Litter reduction caused important alterations in maternal behavior, reducing the total time out of the nest and increasing the frequency of maternal care and lactation in several observation periods, justifying the increased pup's weight gain already demonstrated by this animal model. The practice of maternal exercise did not prevent, but cause the less intensive frequency of non-maternal behavior and lactation in arched-back position, induced by the reduction of litter size. These data demonstrated that small litter size altered maternal behavior, and gestational exercise does not influence significantly these changes.

Genistein attenuates amyloid-beta-induced cognitive impairment in rats by modulation of hippocampal synaptotoxicity and hyperphosphorylation of Tau.

Alzheimer's disease is a progressive neurodegenerative disorder characterized by extracellular accumulation of amyloid-beta (Aß) peptide, which induces synaptic dysfunction, alteration of intracellular signaling pathways, hyperphosphorylation of the Tau protein, and cognitive impairment. Genistein, one of the major isoflavones present in soy and soy products, has been shown to modulate some of the pathogenic events associated with the neurodegeneration process. However, its underlying mechanisms remain to be clarified. Therefore, the objectives of the present study were to evaluate the ability of genistein to protect against Aß1-42-induced cognitive impairment in rats and to elucidate some of the possible mechanisms involved in its neuroprotective effects in the hippocampus. Male Wistar rats received bilateral intracerebroventricular infusions of Aß1-42 (2 nmol) and genistein 10 mg/kg orally for 10 days. The Aß-infused animals showed significant impairment of memory, which was accompanied by the following neurochemical alterations in the hippocampus: decreased levels of the synaptic proteins synaptophysin and postsynaptic density protein 95 (PSD-95), hyperphosphorylation of Tau with increased activation of glycogen synthase kinase-3ß and c-Jun N-terminal kinase, and inactivation of ERK. Treatment with genistein improved Aß-induced cognitive impairment by attenuation of synaptotoxicity, hyperphosphorylation of Tau, and inactivation of ERK. Furthermore, treatment with this soy isoflavone did not cause systemic toxicity. These findings provide further evidence of the neuroprotective effect of genistein in an in vivo model of Aß toxicity and, importantly, extend the current knowledge concerning the mechanisms associated with the neuroprotective effects of this compound in the hippocampus.

Early weaning alters redox status in the hippocampus and hypothalamus of rat pups.

Exposure to environmental factors can program the metabolism, conferring resistance or increasing the risk to chronic disease development in childhood and adulthood. In this sense, lactation is an important period in this window of development. Herein, we investigated the effect of early weaning on neurochemical and behavioral changes in offspring at weaning and adulthood. Female and male pups were divided into four groups: (1) Control weaning (weaning on the PND21, pups were kept with the biological mother); (2) Early Weaning Bromocriptine group (EWB) (pharmacological weaning on PND16); (3) Early Weaning Cross-Fostering group (EWCF) (pups housed with a foster mother on PND16 up to PND21); (4) Early Weaning Without Care group (EWWC) (weaning on PND16, maternal separation). Weight control of pups was recorded from postnatal Day 16 to 59. On the 21st day, part of the pups was euthanized and the hippocampus and hypothalamus were removed for biochemical evaluation. The remaining pups were submitted to behavioral tests on the 60th postnatal day. Early weaning reduced the pups' body weight, in a sex-dependent way. At 60 days of age, male pups of EWCF and EWWC groups have lower body weight compared to control male, and female body weight was lower than male pups. In relation to biochemical changes in the brain, weaning altered the levels of oxidants, increased the enzymatic activity of superoxide dismutase (SOD), and glutathione peroxidase (GPx), as well as induced lipid peroxidation. Weaning was also able to alter long-term memory and induce anxious behavior in pups. Our results demonstrate that the different types of early weaning changed the parameters of redox status in the hippocampus and hypothalamus of pups (21 days old), suggesting a prooxidative profile, in addition, to alter learning/memory and inducing an anxious behavior in male offspring (60 days old).

Comparison of photobiomodulation using either an intraoral or an extraoral laser on oral mucositis induced by chemotherapy in rats.

PURPOSE: The aim of the present study was to compare the effect of intraoral (IO) and extraoral (EO) diode laser irradiation on oral mucositis (OM) induced by 5-fluorouracil (5-FU) in rats. METHODS: Animals (n = 78) were divided into the following groups: negative control (NC), positive control (PC), IO 6 J/cm2, EO with 6 J/cm2 (EO 6 J/cm2), and 12 J/cm2 (EO 12 J/cm2). OM was induced with an intraperitoneal injection of 5-FU and scarification of the buccal mucosa. Over the following 14 days, animals received photobiomodulation (PBM) daily. Clinical and histological evaluation was done by scores at days 8, 10, and 14. The redox state was evaluated by reactive species levels, antioxidant network, and immunohistochemistry analysis. RESULTS: Clinically, on day 8, PBM groups showed lower scores of OM with EO 6 J/cm2 presenting a significantly lower degree compared to PC (p < 0.05). On days 10 and 14, all PBM groups exhibited improvement of OM compared to PC (p < 0.01). On day 8, all PBM groups exhibited an accelerated healing process compared to PC (p < 0.01) and reduction of reactive species (p < 0.001). Also, all PBM groups demonstrated higher levels of antioxidant GPx compared to PC (p < 0.001). Analysis of nitrotyrosine revealed that on day 14, this protein damage marker was significantly reduced in the EO 6 J/cm2 group (p > 0.05). CONCLUSIONS: An EO diode laser protocol promoted positive effects in the clinical, histopathological, and redox state in OM induced by 5-FU in rats. Among the EO protocols, EO 6 J/cm2 showed the most encouraging results.

Adaptive effects of gestational caloric restriction in the mitochondria of Wistar rats' brain: A DOHaD approach.

Developmental origins of health and disease (DOHaD) is a field of biological science dedicated to investigating how different interventions during development affect an individual's life. Diet is an essential way to interact with the environment, and during pregnancy affects not only the mother but also can impact the next generations. One of these interventions is caloric restriction (CR), which has shown positive redox modulation in rats' offspring when malnutrition is responsibly controlled. Considering that mitochondrial metabolism is determinant for redox status, we investigated parameters related to mitochondrial functionality and reactive species levels in offspring's brain from rats delivered to pregnant caloric restricted dams. Therefore, pregnant rats were divided between control (ad libitum food) and CR (20% food restriction plus micronutrients supplementation) groups, and offspring's brain was analyzed on post-natal days (PND) 0, 7, 21, and 60. Mitochondrial function, as well as superoxide content, were decreased in most brain areas on PND0 and went through adaptation, showing increased mass and membrane potential in adulthood. Concerning mitochondrial electron transport system (METS), the most affected area was the cerebellum, which was impaired at birth and activated at adulthood. In conclusion, our results show that gestational CR promotes adaptation from impaired mitochondrial parameters at birth, improving mitochondrial function when compared to control, without increasing superoxide generation, at adult age. More studies are necessary in order to support the use of CR as a clinical approach.

Gestational caloric restriction improves redox homeostasis parameters in the brain of Wistar rats: a screening from birth to adulthood.

Caloric restriction (CR) improves health and life span in animal models. Although CR effects in adult life are well described, little is known about effects on offspring when applied during gestation. Pregnancy is a remarkable period of life, alterations in this stage lead to lifelong consequences, some of which, associated to redox unbalance. Furthermore, gestational overweight is a growing issue that can lead to detrimental outcomes. To address this issue, we divided pregnant rats into control (ad libitum food) and CR groups, which received 20% less food than control. Micronutrients consumption was equalized between groups by oral gavage. Cerebellum, prefrontal cortex, hippocampus, and hypothalamus were evaluated on post-natal day (PND) 0, 7, 21, and 60. We observed increased oxidants content on PND0 in all brain structures, except for the cerebellum. Key enzymatic antioxidant defenses showed decreased activity on PND0. Interestingly, on PND60, we observed a positive modulation of most antioxidant enzymes, especially on the prefrontal cortex and hippocampus. Non-enzymatic antioxidant defenses were decreased at birth and increased during development and adult age. Lipid peroxidation was increased at birth on most structures, and the effect was abolished thereafter. In the prefrontal cortex, lipid peroxidation was unaltered at birth and diminished thereafter, while protein oxidation was increased on PND0 and decreased on PND60. Protein oxidation was also decreased in the cerebellum at adult age. Our results shown controlled gestational CR to improve antioxidant defenses and protect offspring's brain from oxidative stress, especially in adulthood, as a result of developmental metabolic programming.

Physical Exercise During Pregnancy Prevents Cognitive Impairment Induced by Amyloid-ß in Adult Offspring Rats.

Alzheimer's disease (AD) is the main aging-associated neurodegenerative disorder and is characterized by mitochondrial dysfunction, oxidative stress, synaptic failure, and cognitive decline. It has been a challenge to find disease course-modifying treatments. However, several studies demonstrated that regular physical activity and exercise are capable of promoting brain health by improving the cognitive function. Maternal lifestyle, including regular exercise during pregnancy, has also been shown to influence fetal development and disease susceptibility in adulthood through fetal metabolism programming. Here, we investigated the potential neuroprotective role of regular maternal swimming, before and during pregnancy, against amyloid-ß neurotoxicity in the adult offspring. Behavioral and neurochemical analyses were performed 14 days after male offspring received a single, bilateral, intracerebroventricular (icv) injection of amyloid-ß oligomers (AßOs). AßOs-injected rats of the sedentary maternal group exhibited learning and memory deficits, along with reduced synaptophysin, brain-derived neurotrophic factor (BDNF) levels, and alterations of mitochondrial function. Strikingly, the offspring of the sedentary maternal group had AßOs-induced behavioral alterations that were prevented by maternal exercise. This effect was accompanied by preventing the alteration of synaptophysin levels in the offspring of exercised dams. Additionally, offspring of the maternal exercise group exhibited an augmentation of functional mitochondria, as indicated by increases in mitochondrial mass and membrane potential, α-ketoglutarate dehydrogenase, and cytochrome c oxidase enzymes activities. Moreover, maternal exercise during pregnancy induced long-lasting modulation of fusion and fission proteins, Mfn1 and Drp1, respectively. Overall, our data demonstrates a potential protective effect of exercise during pregnancy against AßOs-induced neurotoxicity in the adult offspring brain, by mitigating the neurodegenerative process triggered by Alzheimer-associated AßOs through programming the brain metabolism.

Effect of maternal antioxidant supplementation and/or exercise practice during pregnancy on postnatal overnutrition induced by litter size reduction: Brain redox homeostasis at weaning.

Prenatal and early postnatal environments can permanently influence health throughout life. Early overnutrition increases the risk to develop chronic diseases. Conversely, the intake of flavonoids and exercise practice during pregnancy seem to promote long-term benefits to offspring. We hypothesized that benefic interventions during pregnancy could protect against possible postnatal neurochemical alterations caused by overnutrition induced by reduced litter size. Female Wistar rats were divided into four groups: (1) sedentary + vehicle, (2) sedentary + naringenin, (3) swimming exercise + vehicle, and (4) swimming exercise + naringenin. One day after birth, the litter was culled to 8 pups (control) or 3 pups (overfed) per dam, yielding control and overfed subgroups for each maternal group. Serum of 21-days-old pups was collected, also the cerebellum, hippocampus, and hypothalamus were dissected. Litter size reduction increased fat mass and enhanced body weight. Maternal interventions, when isolated, caused reduced glucose serum levels in offspring nurtured in control litters. In the cerebellum, reducing the litter size decreased the activity of thioredoxin reductase, which was prevented by maternal supplementation with naringenin. Hippocampus and hypothalamus have shown altered antioxidant enzymes activities in response to litter size reduction. Interestingly, when maternal exercise and naringenin supplementation were allied, the effect disappeared, suggesting a concurrent effect of the two maternal interventions. In conclusion, exercise or naringenin supplementation during pregnancy can be important interventions for combating the increasing rates of overweight during the infancy and its related neurochemical changes, especially when applied isolated.