Memory impairments and increased GFAP expression in hippocampal astrocytes following hypercaloric diet in rats

Abstract

Objective: Hypothalamic inflammation and glial fibrillary acidic protein (GFAP) overexpression in astrocytes are well described in obese animals, as are some cognitive and memory deficits. As the hippocampus plays important roles in the consolidation of information, this investigation aimed to observe the memory function and the astrocyte expression of GFAP in the hippocampus of rats that received either a hypercaloric or a normocaloric diet. Methods: Adult male Wistar rats received a high-fat (cafeteria) or a standard diet for 60 days. On the 61st day, the rats were submitted to the novel object recognition (NOR) test at three and 24 hours after the first contact with objects, to assess short-term and long-term memory, respectively. Thereafter, the rats were euthanized and their brains were collected for GFAP immunohistochemical investigation in the hippocampus (CA1, CA2, CA3 areas) and hypothalamus (periventricular and arcuate nuclei). Astrocytic reactivity was assessed by morphometry. Different white adipose tissue depots and brown adipose tissue were weighed to calculate the adiposity index. Results: The hypercaloric diet increased body weight gain, adiposity index, white adipose tissue weight (epididymal, subcutaneous and retroperitoneal) and brown adipose tissue weight. Rats fed with the hypercaloric diet showed short-term and long-term memory impairments in the NOR test, as well as increased GFAP expression in astrocytes from all analyzed hypothalamic and hippocampal areas. Conclusion: This astrogliosis suggests that the neuroinflammatory response also occurs in the hippocampus and may be involved in the memory losses observed in obese/overweight animals.

Brain Alterations in High Fat Diet Induced Obesity: Effects of Tart Cherry Seeds and Juice

“…Cytoskeletal breakdown has been reported to occur in several central and peripheral neurodegenerative diseases, and it may increase neuronal susceptibility to ischemia or hypoxia [53,55], two situations more common in obesity than in normal conditions. GFAP overexpression in astrocytes was recently described in obese animals [56]. Our findings are similar.…”

“…Our findings are similar. This astrogliosis suggests that the neuroinflammatory response also occurs in the hippocampus [56]. Additionally, microglia activation has been reported to be associated with the obesity phenotype [57,58], as shown by the microglia morphology modifications stained for IBA-1 at the level of the frontal cortex and hippocampus.…”

Characterization of Hippocampal Histomorphology Following R. vomitoria Root Extract Treatment

“…GFAP is an intermediate filament-III protein present in astrocytes and therefore serves as its marker (Yang and Wang, 2015). Increased GFAP expression indicates astrogliosis (Bondan et al, 2019;Trautz et al, 2019) and RV has been reported with such action on astrocytes (Ekong et al, 2016b(Ekong et al, , 2020Nduohosewo and Ekong, 2020). Decreased GFAP is indicative of detrimental and/or diseased conditions in nervous tissues (Bondan et al, 2013;Molina et al, 2018), which may be associated with astrocytes remodelling after injury (Bondan et al, 2013).…”

Early postnatal exposure to a cafeteria diet interferes with recency and spatial memory, but not open field habituation in adolescent rats

“…Human obesity is also being linked to cognitive dysfunctions (Contu & Hawkes, 2017; Francis & Stevenson, 2013; Morris et al., 2015; Pedditzi et al., 2016; Reichelt et al., 2018; Stevenson et al., 2020; Yeomans, 2017), and even a short four day exposure to a high fat‐high sugar breakfast can interfere with human memory (Attuquayefio et al., 2017). In this context, experimental studies demonstrated that cafeteria feeding has detrimental effects in a variety of rodent memory tests (Abbott et al., 2019; Andre et al., 2014; Beilharz et al., 2014, 2018; Bondan et al., 2019; Darling et al., 2013; Ferreira et al., 2018; Kendig et al., 2019; Kosari et al., 2012; Lewis et al., 2019; Reichelt et al., 2019; Reichelt, Loughman, et al., 2018; Tran & Westbrook, 2018). Whereas many of these studies have been conducted in adult rats, fewer studies specifically addressed memory effects of a cafeteria diet in adolescent rats (Noble & Kanoski, 2016; Reichelt et al., 2019; Reichelt, Loughman, et al., 2018).…”

“…| 573 WAIT eT Al. Beilharz et al, 2014Beilharz et al, , 2018Bondan et al, 2019;Darling et al, 2013;Ferreira et al, 2018;Kendig et al, 2019;Kosari et al, 2012;Lewis et al, 2019;Reichelt et al, 2019;Reichelt, Loughman, et al, 2018;Tran & Westbrook, 2018). Whereas many of these studies have been conducted in adult rats, fewer studies specifically addressed memory effects of a cafeteria diet in adolescent rats (Noble & Kanoski, 2016;Reichelt et al, 2019;Reichelt, Loughman, et al, 2018).…”