Early stress affects neurogenesis in the rat rostral migratory stream

Abstract

Early stress affects neurogenesis in the rat rostral migratory stream Abstract: Stressful experience during the early postnatal period may influence processes associated with neurogenesis (i.e. proliferation, cell death, appearance of astrocytes or cell differentiation) in the neonatal rat rostral migratory stream (RMS). To induce stress, pups were subjected to maternal deprivation daily for three hours, starting from the first postnatal day till the seventh postnatal day. Immunohistochemical methods were used to visualize proliferating cells and astrocytes; dying cells and nitrergic cells were visualizedusinghistochemicalstaining.Quantitativeanalysisshowedthatmaternaldeprivationdecreasedthenumberofproliferating cells and significantly increased the number of dying cells in the RMS. Maternal deprivation did not influence the appearance of astrocytes in the RMS, but caused premature differentiation of nitrergic cells. In control rats, nitrergic cells can be observed in the RMS as early as the tenth postnatal day. In maternally deprived pups, these cells were detected as early as the seventh postnatalday. TheobservedearlierappearanceofnitrergiccellsintheRMSwasassociatedwithalteredproliferationandincreased cell dying and this observation supports the hypothesis that nitric oxide has an anti-proliferative role in the RMS. Our study demonstrates that maternal deprivation represents a stressful condition with a profound impact on early postnatal neurogenesis.

Delayed maturation and altered proliferation within the rat rostral migratory stream following maternal deprivation

“… 28 Our results of quantitative analysis showed, that the response of Ki-67-positive cells to stress was not uniform in the vertical arm, elbow and horizontal arm of the RMS. Unlike the overall decrease of BrdU labeled cells in all three parts of the RMS following maternal deprivation, 35 the decrease of the number of Ki-67-positive cells was restricted only to the RMS caudal part, i.e., to the vertical arm. Surprisingly, in the elbow and in the horizontal arm of the RMS we have observed increased amount of proliferating cells.…”

“…Maternal deprivation induced striking changes also in proliferation activity of Ki-67-positive neuronal precursors within the migratory pathway. Using a similar experimental paradigm, previously we have shown that maternal deprivation 35 caused significant changes in the number of proliferating cells labeled with the S-phase marker BrdU within the rat RMS. BrdU immunohistochemistry has regularly been used for estimating proliferating cells fraction in the RMS to map physiological dynamics at various postnatal ages 15 and in several experimental interventions.…”

Regional differences of proliferation activity in the spinal cord ependyma of adult rats

“…The proliferation activity of ependymal cells was assessed by the most commonly used markers of cell division: BrdU and Ki-67, respectively. BrdU immunohistochemistry has regularly been applied for estimating proliferating cells number in the main neurogenic region of the brain under physiological conditions [24] and in experimental interventions [25,26]. The more recently introduced marker, Ki-67 is also commonly used for detection of proliferation in the brain [27] and the spinal cord [16].…”