Study in the changes of the proportions and numbers of the various glial cell types in the spinal cord of neonatal and young adult rats

Abstract

Glioblasts, astrocytes, microglia and the three classes of oligodendrocytes were enumerated in the grey and white matter of the spinal cord of rats of various ages. Both regions showed fairly similar results. Glioblasts, which made up the major glial population in the newborn rats, declined steadily with age and their number became negligible by 22 days post natum. They were absent in the young adult rats (aged 70 days). Contrary to this, the major glial types increased rapidly with age, the increase being most drastic in the oligodendrocy tic population. The growth continued through about 22 days after birth and became more or less stabilized thereafter. Of the three classes of oligodendrocytes, the light cells appeared to develop first, followed by the medium dense cells and subsequently the dark ones. While there was a gradual disappearance of the light and medium dense cells with age, there was an accumulation of the dark cells, so that they were predominant in the spinal cord of the young adult rats.

Mimicking the Neurotrophic Factor Profile of Embryonic Spinal Cord Controls the Differentiation Potential of Spinal Progenitors into Neuronal Cells

“…In fact, we demonstrated the increase of NGF, BDNF and GDNF gene expression within the developmental spinal cord, which corresponds temporally with the period of differentiation and maturation of neurons [23]–[24], and also the simultaneous down-regulation of NGF, BDNF and GDNF gene expression and up-regulation of CNTF gene expression, which are coincident with postnatal gliogenesis [24], [25].…”

Neuroinflammation modulates distinct regional and temporal clinical responses in ALS mice

“…A recent study concluded that there are marked differences in the regional density, distribution and/or activity of microglia in a MPTP-induced neurodegenerative mouse model of Parkinson’s disease and that microglial-derived factors influenced the region-specific role for this cell type (Sriram et al, 2006). Furthermore, in the rat spinal cord, microglial population represents 7% of the white and 11% of the grey matter, and after pathological intrathecal stimulation with IFN-γ, the highest numbers of microglia were detected in the lumbar spinal cord, suggesting a region-specific microglial regulation within the spinal cord (Ling, 1976; Vass and Lassmann, 1990). In this report, the detected microglial heterogeneity may have been dictated by the local motoneuron/astrocytic/lymphocyte microenvironments that the microglia encountered in the two anatomically distinct regions of their spinal cord, which in turn induced a specific set of different mRNA expression profiles in the respective resident microglia in these two regions; the distinct phenotypes of activated microglia might result from this heterogeneity (Sawada, 2009).…”

Expression of cyclooxygenase‐2 and microsomal prostaglandin‐E synthase in amoeboid microglial cells in the developing brain and effects of cyclooxygenase‐2 neutralization on BV‐2 microglial cells

“…It is therefore suggested that COX‐2 and mPGES‐1 and their product PGE 2 play important role in local inflammation in normal development of the periventricular white matter (Deng et al, 2008). It is noteworthy that natural occurrence of cellular and axonal degeneration is common in the callosal tissue in the postnatal rat brain (Ling, 1976). It is suggested that the natural occurring cell death may act as a stimulus to AMC and induce local inflammation.…”