Effects of monosodium glutamate treatment on calretinin-immunoreactive neurons in hippocampus of postnatal rats

Introduction. Calretinin (CR) is a protein, which is present in GABAergic neurons and belongs to the calcium-binding proteins family. It may reduce the excitotoxicity phenomenon through its Ca2+ buffering properties. This phenomenon is due to the increase of calcium ions levels caused by the excess of glutamate — the main excitatory neurotransmitter. The aim of the study was to investigate alterations of calretinin-immunoreactivity in neurons of hippocampal CA1 region and dentate gyrus with hilus in 10 day-old rats treated with monosodium glutamate (MSG). Material and methods. Ten 7 day-old Wistar rats were used. The MSG-group consisted of 5 MSG-treated rats at a dose of 4 g/kg b.w. for 3 consecutive days and the second group consisted of 5 control animals. After euthanasia the brains containing hippocampus were dissected and embedded in paraffin blocks. The immunohi­stochemical peroxidase-antiperoxydase reaction was performed on tissue sections. The morphometric analyses of CR-immunopositive neurons: density, percentage ratio to the density of all cells and an assessment of digital immunostaining intensity were performed. Results. The distribution of the CR-immunoreactive neurons in the hippocampus was irregular. In the MSG-group there were single cells, which were more intensely stained than in control animals. Some of cells contained processes of different length. The density of CR-immunopositive cells and their percentage ratio to the density of all cells did not change significantly after MSG treatment. However, there was a statistically significant increase in the staining intensity of CR-immunopositive cells. Conclusions. The obtained results indicate that CR-positive cells in P7–P10 rats are only slightly affected by MSG in CA1 region and dentate gyrus with hilus of the hippocampus

Reactivity of astrocytes in hippocampal CA1 area in rats after administration of habanero peppers

Introduction. Astrocytes react to microenvironmental changes. Their reactivity is manifested by an increase in glial fibrillary acidic protein (GFAP) and S100b protein levels, hypertrophy and hyperplasia. The aim of the study was to analyse immunoreactive GFAP (GFAP-IR) and S100b (S100b-IR) astrocytes of hippocampal CA1 area in adult rats intragastrically (i.g.) treated with habanero peppers. Material and methods. Brains from 10 control rats (group C) and 10 rats receiving oil suspension of habanero fruits for 7 days (group I-7) or 28 days (group II-28) were used. Antibodies against GFAP and S100b were used for immunohistochemistry. Morphology and distribution of astrocytes was evaluated under light microscope and their density was quantitatively analysed. Results. In the CA1 hippocampal area of group II-28 rats, GFAP-IR cells with numerous, branched processes were observed. S100b-IR astrocytes had delicate, single processes in comparison with cells without processes observed in groups I-7 and C. In groups I-7 and II-28, GFAP-IR astrocytes’ density significantly increased in SR — stratum radiatum of hippocampal CA1 area. In group I-7, a density of cells with the expression of S100b was significantly increased in SO — stratum oriens layer. In group II-28, the density of S100b-IR astrocytes was decreased. Conclusions. Habanero peppers administrated to rats, especially for a longer time, caused reactive changes in the astrocytes in hippocampal CA1 area, and thus these glial cells may protect neurons against excitotoxic damage

Maternal acrylamide exposure changes intestinal epithelium, immunolocalization of leptin and ghrelin and their receptors, and gut barrier in weaned offspring

Abstract Acrylamide (ACR) is an amide formed as a byproduct in many heat-processed starchy-rich foods. In utero ACR exposure has been associated with restricted fetal growth, but its effects of postnatal functional development of small intestine is completely unknown. The current study investigated the time- and segment-dependent effects of prenatal ACR exposure on morphological and functional development of small intestine in weaned rat offspring. Four groups of pregnant female Wistar rats were exposed to ACR (3 mg/kg b.w./day) for 0, 5, 10 and 15 days during pregnancy. Basal intestinal morphology, immunolocalization of gut hormones responsible for food intake and proteins of intestinal barrier, activity of the intestinal brush border disaccharidases, apoptosis and proliferation in intestinal mucosa were analyzed in offspring at weaning (postnatal day 21). The results showed that in utero ACR exposure disturbs offspring gut structural and functional postnatal development in a time- and segment-depended manner and even a short prenatal exposure to ACR resulted in changes in intestinal morphology, immunolocalization of leptin and ghrelin and their receptors, barrier function, activity of gut enzymes and upregulation of apoptosis and proliferation. In conclusion, prenatal ACR exposure disturbed the proper postnatal development of small intestine