Obese male Zucker rats exhibit dendritic remodeling in neurons of the hippocampal trisynaptic circuit as well as spatial memory deficits.

Obesity is characterized by excessive fat accumulation. The Zucker rat displays genetic obesity due to a mutation in the leptin receptor gene; this model is of great interest because of its similarity to human obesity. Brain regions may be affected by obesity, but detailed information is lacking. In the present study, we analyzed the morphology of neurons in the hippocampal trisynaptic circuit as well as the spatial memory of obese Zucker rats. We performed two experiments. Each experiment contained two experimental groups: the control group (male Long Evans rats) and the study group (obese male Zucker rats). We monitored the body weights of all rats over 4 weeks. In the first experiment, we analyzed the morphology of hippocampal neurons. Under anesthesia, we measured the abdominal and hip circumferences and collected at least 1 ml of blood to assess serum glucose (GLU), triglyceride (TGC), and cholesterol (COL) concentrations. We perfused the brains of these rats with 0.9% saline solution, incubated the brains in Golgi-Cox solution, and subsequently evaluated the morphology of pyramidal neurons in the hippocampus (the CA1-CA3 regions) and the entorhinal cortex as well as the morphology of granule neurons in the dentate gyrus. In the second experiment, we assessed the spatial memory of animals with the Morris water maze. The Zucker rats had an obese phenotype, as indicated by their elevated body weight and increased abdominal and hip circumferences as well as elevated GLU, COL, and TGC concentrations. Analysis of neurons from the specified regions in obese male Zucker rats indicated reduced dendritic arborization and reduced dendritic spine density. In terms of spatial learning and memory, the obese Zucker rats exhibited intact spatial learning (i.e., of platform location) but deficits in spatial memory. These data provide evidence that obesity alters the morphology and function of hippocampal neurons.

Epigenetic mechanisms of particulate matter exposure: air pollution and hazards on human health.

Environmental pollution nowadays has not only a direct correlation with human health changes but a direct social impact. Epidemiological studies have evidenced the increased damage to human health on a daily basis because of damage to the ecological niche. Rapid urban growth and industrialized societies importantly compromise air quality, which can be assessed by a notable accumulation of air pollutants in both the gas and the particle phases. Of them, particulate matter (PM) represents a highly complex mixture of organic and inorganic compounds of the most variable size, composition, and origin. PM being one of the most complex environmental pollutants, its accumulation also varies in a temporal and spatial manner, which challenges current analytical techniques used to investigate PM interactions. Nevertheless, the characterization of the chemical composition of PM is a reliable indicator of the composition of the atmosphere, the quality of breathed air in urbanized societies, industrial zones and consequently gives support for pertinent measures to avoid serious health damage. Epigenomic damage is one of the most promising biological mechanisms of air pollution-derived carcinogenesis. Therefore, this review aims to highlight the implication of PM exposure in diverse molecular mechanisms driving human diseases by altered epigenetic regulation. The presented findings in the context of pan-organic cancer, fibrosis, neurodegeneration and metabolic diseases may provide valuable insights into the toxicity effects of PM components at the epigenomic level and may serve as biomarkers of early detection for novel targeted therapies.