Biochemical Changes Indicate Developmental Stage in the Hippocampal Formation

Abstract

The literature showing how age of humans or animals influences the IR absorption spectra recorded in different brain regions is very poor. A very limited number of studies used FTIR microspectroscopy for analysis of the aging process, however there is lack of data concerning the biomolecular changes occurring in the course of postnatal development of the central nervous system. Therefore, in this paper the topographic and semiquantitative biochemical changes occurring within the rat hippocampus during postnatal development were examined. To achieve the goal of the study, three groups of normal male rats differing in age were investigated. These were 6, 30, and 60 day old animals, and the chosen ages correspond to the neonatal period, childhood, and early adulthood in humans, respectively. Already, preliminary topographic analysis identified a number of significant changes in the accumulation of biomolecules within the hippocampal formation occurring during brain development. Such observation was confirmed by further semiquantitative analysis of intensities of selected absorption bands or ratios of their intensities. The detailed examinations were done for four hippocampal cellular layers (multiform, molecular, pyramidal, and granular layers), and the results showed that the accumulation of most biomolecules, including both saturated and unsaturated lipids as well as compounds containing phosphate and carbonyl groups, was significantly higher in adulthood comparing to the neonatal period. What is more, the increases in their levels were observed mostly between 6th and 30th days of animals’ life. The unsaturation level of lipids did not change during postnatal development, although the differences in unsaturated and saturated lipids contents were noticed between examined animal groups. Significant differences in relative secondary structure of proteins were found between young adult rats and animals in neonatal period for which the relative level of proteins with β-type secondary structure was the highest.

Characterization of Ionic and Lipid Gradients within Corpus Callosum White Matter after Diffuse Traumatic Brain Injury in the Rat

“…If so, it is still not known if such processes are the initial stages of remyelination or, if the net lipid increase reflects abnormal myelination and oligodendrocyte dysfunction. If the latter, this would be likely contribute to the extended, incorrectly folded myelin layers observed through electron microscopy in other studies. , FTIR imaging studies by others have revealed increased lipid levels in brain cells associated with inflammation, such as during chronic pain. , The elevated lipid content observed in the lateral corpus callosum following dTBI in this study may, therefore, possibly be a marker of inflammation, which has been shown to occur in this model …”

“…51,52 FTIR imaging studies by others have revealed increased lipid levels in brain cells associated with inflammation, such as during chronic pain. 55,34 The elevated lipid content observed in the lateral corpus callosum following dTBI in this study may, therefore, possibly be a marker of inflammation, which has been shown to occur in this model. 41 XFM Elemental Mapping Reveals Effects of dTBI on the Levels of Metal Ions and Ionic Gradients across Lateral and Medial Corpus Callosum White Matter.…”

“…Recent advances in synchrotron X-ray fluorescence microscopy (XFM) enable rapid elemental mapping of brain tissue sections, at micrometer spatial resolution, to study the distribution and concentration of elements like those noted above. − The advantages of “multimodal” imaging are also gaining increasing recognition, , where vibrational spectroscopic methods such as Fourier transform infrared spectroscopy (FTIR) or Raman spectroscopy are applied to characterize tissue biochemistry in association with elemental distributions revealed by XFM. ,,− FTIR-imaging is increasingly used as an analytical tool to investigate holistic biochemical composition at the cellular (i.e., micrometer spatial resolution) or near-cellular (i.e., 10–50 μm spatial resolution) level . This sort of multimodal approach has been used to associate lipid homeostasis with ionic or elemental gradients after ischemic , or hemorrhagic stroke , or to associate protein aggregation with brain metal content during dementia or Alzheimer’s disease. ,, …”

“…24,28,31−33 FTIR-imaging is increasingly used as an analytical tool to investigate holistic biochemical composition at the cellular (i.e., micrometer spatial resolution) or near-cellular (i.e., 10−50 μm spatial resolution) level. 34 This sort of multimodal approach has been used to associate lipid homeostasis with ionic or elemental gradients after ischemic 28,33 or hemorrhagic stroke 35,36 or to associate protein aggregation with brain metal content during dementia or Alzheimer's disease. 32,37,38 In this study, we have applied a multimodal approach using FTIR biochemical imaging and XFM elemental mapping to characterize biochemical alterations, ionic gradients, and transition metal content in the medial and lateral regions of the corpus callosum white matter of rodents, and surrounding brain structures, following dTBI, created using a wellestablished and characterized model of dTBI in rodents, which model clinical aspects of human brain injury, particularly to white matter structures such as the corpus callosum.…”

Alarmin HMGB1 Plays a Detrimental Role in Hippocampal Dysfunction Caused by Hypoxia-Ischemia Insult in Neonatal Mice: Evidence from the Application of the HMGB1 Inhibitor Glycyrrhizin

“…20 However, whether HMGB1 is undeniably involved in the pathogenesis of HIBI and its relationship with hippocampal dysfunction caused by HIBI remain to be elucidated. As the hippocampal region of the brain is crucial for declarative and episodic memory for a broad range of materials 21 and plays an important role in the modulation of emotional behavior, 22,23 we investigated changes in hippocampal function after HI insult.…”