GFAP Expression in Astrocytes of Suprachiasmatic Nucleus and Medial Preoptic Area are Differentially Affected by Malnutrition during Rat Brain Development

Abstract

The aim of the present study was investigate, in young rats, the effects of malnutrition on astrocyte distribution of two hypothalamic regions, the circadian pacemaker suprachiasmatic nucleus (SCN) and the medial preoptic area (MPA). Control rats were born from mothers fed on commercial diet since gestation and malnourished rats from mothers fed on multideficient diet, from the beginning of gestation (GLA group) or from the onset of lactation (LA group). After weaning, pups received ad libitum the same diet as their mothers, and were maintained under a 12/12 h light/dark cycle. The animals were analyzed either at 30-33, or 60-63 days of life. Brain coronal sections (50 microm) were processed to visualize glial fibrillary acidic protein (GFAP) immunoreactivity. Compared to control rats, both malnourished groups of 30 and 60 days exhibited a reduced number of GFAP-immunoreactive astrocytes in the SCN. The total GFAP-immunoreactive area in the SCN of the GLA group differed from the control group at both age ranges analyzed. The GFAP expression as measured by the relative optical density (ROD) exhibited a 50-60% reduction in the MPA in both malnourished groups, compared to controls. The results suggest that malnutrition early in life leads to alterations in gliogenesis or glial cell proliferation in both nuclei, being these alterations greater in the MPA. Compensatory plasticity mechanisms in the GFAP-expression seem to be developed in the astrocyte differentiation process in the SCN, especially when the malnutrition is installed from the lactation.

Reductions in hypothalamic Gfap expression, glial cells and α-tanycytes in lean and hypermetabolic Gnasxl-deficient mice

“…However, changes in hypothalamic neuronal networks have been little analysed at the histological level in rodent models of postnatal undernutrition [ 48 ], and glial or tanycyte abnormalities have not been reported so far. In support of our findings in Gnasxl m+/p- mice, some studies on the effects of foetal and/or postnatal protein restriction and malnutrition described similar reductions in Gfap expression and glial cell numbers in the suprachiasmatic nucleus and the medial preoptic area [ 49 , 50 ]. By contrast, genetic or diet-induced mouse models of obesity have been much better characterised for changes in the hypothalamus.…”

Nutrition-dependent influence of peripheral electrical stimulation during brain development on cortical spreading depression in weaned rats

“…The underlying mechanisms for this frequency-dependent effect still need to be identified. Factors like malnutrition-related selective alterations of different brain regions (Mendonça et al 2004), or differential changes in distinct neurotransmitters systems (Stern et al 1974;Wiggins et al 1984) could be involved in that effect.…”

Misadjustment of diurnal expression of core temperature and locomotor activity in lactating rabbits associated with maternal over-nutrition before and during pregnancy

“…The homeostatic and chronostatic functions of body temperature are is regulated by the hypothalamic preoptic area and SCN, respectively [81]. Experimental evidence indicates that the maternal nutritional condition alters the cytoarchitecture of these hypothalamic structures in the offspring [82,83] and causes long-lasting disruption in the diurnal expression of clock genes in the liver and heart of the offspring [48]. Further studies are needed to determine whether the exposure to suboptimal environment, such as HFCD, during intrauterine development in rabbits has an impact on the hypothalamic regulation of temperature, on the molecular clock-work of the central pacemaker, and on the peripheral oscillators.…”