Açaí (Euterpe oleracea) pulp-enriched diet induces anxiolytic-like effects and improves memory retention.

Background: Açaí (Euterpe oleracea) has a rich nutritional composition, showing nutraceutical and protective effects in several organs. In this study, the effects of an açaí-enriched diet on motor performance, anxiety-like behavior, and memory retention were deeply investigated. Methods: Eight-week male Wistar rats were fed with an Euterpe oleracea (EO) pulp-enriched diet, an olive oil-enriched (OO) diet (polyunsaturated fatty acid [PUFA] fat control diet), or a chow diet for 31 days (28 days pre-treatment and 3 days during behavioral tests). Afterward, animals were submitted to a battery of behavioral tests to evaluate spontaneous motor behavior (open-field test), anxiety-like behavior (elevated plus maze and open-field test), and memory retention (step-down). Oxidative stress in the hippocampus was evaluated by a lipid peroxidation assay. Results: EO-enriched diet did not influence the body weight and food intake but increased the glucose plasmatic level after 31 days under this diet. However, a similar fat-enriched diet stimulated a marked weight gain and reduced the food intake, followed by changes in the plasmatic lipid markers. EO-enriched diet preserved the motor spontaneous performance, increased the exploration in the aversive environment (anxiolytic-like effects), and elevated the latency to step-down (improved memory retention). The EO-enriched diet also reduced the level of lipid peroxidation in the hippocampus. These positive effects of EO-enriched diet can greatly support the usage of this diet as a preventive therapy. Conclusion: Taken together, the current study suggests that Euterpe oleracea-enriched diet promotes anxiolytic-like effects and improves memory consolidation, possibly due to the reduced levels of lipid peroxidation in the hippocampus.

Environmental Enrichment Improved Learning and Memory, Increased Telencephalic Cell Proliferation, and Induced Differential Gene Expression in Colossoma macropomum.

Fish use spatial cognition based on allocentric cues to navigate, but little is known about how environmental enrichment (EE) affects learning and memory in correlation with hematological changes or gene expression in the fish brain. Here we investigated these questions in Colossoma macropomum (Teleostei). Fish were housed for 192 days in either EE or in an impoverished environment (IE) aquarium. EE contained toys, natural plants, and a 12-h/day water stream for voluntary exercise, whereas IE had no toys, plants, or water stream. A third plus maze aquarium was used for spatial and object recognition tests. Compared with IE, the EE fish showed greater learning rates, body length, and body weight. After behavioral tests, whole brain tissue was taken, stored in RNA-later, and then homogenized for DNA sequencing after conversion of isolated RNA. To compare read mapping and gene expression profiles across libraries for neurotranscriptome differential expression, we mapped back RNA-seq reads to the C. macropomum de novo assembled transcriptome. The results showed significant differential behavior, cell counts and gene expression in EE and IE individuals. As compared with IE, we found a greater number of cells in the telencephalon of individuals maintained in EE but no significant difference in the tectum opticum, suggesting differential plasticity in these areas. A total of 107,669 transcripts were found that ultimately yielded 64 differentially expressed transcripts between IE and EE brains. Another group of adult fish growing in aquaculture conditions were either subjected to exercise using running water flow or maintained sedentary. Flow cytometry analysis of peripheral blood showed a significantly higher density of lymphocytes, and platelets but no significant differences in erythrocytes and granulocytes. Thus, under the influence of contrasting environments, our findings showed differential changes at the behavioral, cellular, and molecular levels. We propose that the differential expression of selected transcripts, number of telencephalic cell counts, learning and memory performance, and selective hematological cell changes may be part of Teleostei adaptive physiological responses triggered by EE visuospatial and somatomotor stimulation. Our findings suggest abundant differential gene expression changes depending on environment and provide a basis for exploring gene regulation mechanisms under EE in C. macropomum.

Protective effect of prolactin against methylmercury-induced mutagenicity and cytotoxicity on human lymphocytes.

Mercury exhibits cytotoxic and mutagenic properties as a result of its effect on tubulin. This toxicity mechanism is related to the production of free radicals that can cause DNA damage. Methylmercury (MeHg) is one of the most toxic of the mercury compounds. It accumulates in the aquatic food chain, eventually reaching the human diet. Several studies have demonstrated that prolactin (PRL) may be differently affected by inorganic and organic mercury based on interference with various neurotransmitters involved in the regulation of PRL secretion. This study evaluated the cytoprotective effect of PRL on human lymphocytes exposed to MeHg in vitro, including observation of the kinetics of HL-60 cells (an acute myeloid leukemia lineage) treated with MeHg and PRL at different concentrations, with both treatments with the individual compounds and combined treatments. All treatments with MeHg produced a significant increase in the frequency of chromatid gaps, however, no significant difference was observed in the chromosomal breaks with any treatment. A dose-dependent increase in the mitotic index was observed for treatments with PRL, which also acts as a co-mitogenic factor, regulating proliferation by modulating the expression of genes that are essential for cell cycle progression and cytoskeleton organization. These properties contribute to the protective action of PRL against the cytotoxic and mutagenic effects of MeHg.

Beneficial effects of multisensory and cognitive stimulation on age-related cognitive decline in long-term-care institutions.

The aim of the present report was to evaluate the effectiveness and impact of multisensory and cognitive stimulation on improving cognition in elderly persons living in long-term-care institutions (institutionalized [I]) or in communities with their families (noninstitutionalized [NI]). We compared neuropsychological performance using language and Mini-Mental State Examination (MMSE) test scores before and after 24 and 48 stimulation sessions. The two groups were matched by age and years of schooling. Small groups of ten or fewer volunteers underwent the stimulation program, twice a week, over 6 months (48 sessions in total). Sessions were based on language and memory exercises, as well as visual, olfactory, auditory, and ludic stimulation, including music, singing, and dance. Both groups were assessed at the beginning (before stimulation), in the middle (after 24 sessions), and at the end (after 48 sessions) of the stimulation program. Although the NI group showed higher performance in all tasks in all time windows compared with I subjects, both groups improved their performance after stimulation. In addition, the improvement was significantly higher in the I group than the NI group. Language tests seem to be more efficient than the MMSE to detect early changes in cognitive status. The results suggest the impoverished environment of long-term-care institutions may contribute to lower cognitive scores before stimulation and the higher improvement rate of this group after stimulation. In conclusion, language tests should be routinely adopted in the neuropsychological assessment of elderly subjects, and long-term-care institutions need to include regular sensorimotor, social, and cognitive stimulation as a public health policy for elderly persons.

Estradiol reduces cumulative mercury and associated disturbances in the hypothalamus-pituitary axis of ovariectomized rats.

The aim of this research was to verify the incidence of endocrine dysfunction associated with mercury intoxication in the hypothalamus-pituitary reproductive system of normally cycling or castrated female rats and the possible protective action of estrogen replacement therapy. We found no differences in the frequency of estrus cycle stages (diestrus I, diestrus II, proestrus, and estrus) in normally cycling female rats during 54 days of daily oral administration of 0.004, 0.02, and 1 mg/kg MeHgCl. Conversely, the higher dose (1 mg/kg) induced a significant decrease in content of luteinizing hormone releasing hormone (LHRH) into the medial hypothalamus when administered daily during 3 days in ovariectomized rats. This effect was associated with increased levels of mercury found in the anterior pituitary gland and medial hypothalamus, rather than the anterior and posterior hypothalamus, striatum or cerebellum. A decrease in plasma levels of luteinizing hormone (LH) was also detected after administration of 7.5 mg/kg MeHgCl. These disturbances in LHRH and LH secretion induced by mercury were abolished or superimposed (respectively) by estrogenic replacement therapy (0.025 mg/kg 17beta estradiol cypionate, intramuscular). These effects were associated with a significant reduction in mercury content of the anterior pituitary gland and medial hypothalamus, suggesting a protective estrogenic effect.