Short-term, moderate exercise is capable of inducing structural, bdnf-independent hippocampal plasticity

Abstract

Exercise is known to improve cognitive functions and to induce neuroprotection. In this study we used a short-term, moderate intensity treadmill exercise protocol to investigate the effects of exercise on usual markers of hippocampal synaptic and structural plasticity, such as synapsin I (SYN), synaptophysin (SYP), neurofilaments (NF), microtubule-associated protein 2 (MAP2), glutamate receptor subunits GluR1 and GluR2/3, brain-derived neurotrophic factor (BDNF) and glial fibrillary acidic protein (GFAP). Immunohistochemistry, Western blotting and real-time PCR were used. We also evaluated the number of cells positive for the proliferation marker 5-bromo-2-deoxyuridine (BrdU), the neurogenesis marker doublecortin (DCX) and the plasma corticosterone levels. Adult male Wistar rats were adapted to a treadmill and divided into 4 groups: sedentary (SED), 3-day exercise (EX3), 7-day exercise (EX7) and 15-day exercise (EX15). The protein changes detected were increased levels of NF68 and MAP2 at EX3, of SYN at EX7 and of GFAP at EX15, accompanied by a decreased level of GluR1 at EX3. Immunohistochemical findings revealed a similar pattern of changes. The real-time PCR analysis disclosed only an increase of MAP2 mRNA at EX7. We also observed an increased number of BrdU-positive cells and DCX-positive cells in the subgranular zone of the dentate gyrus at all time points and increased corticosterone levels at EX3 and EX7. These results reveal a positive effect of short-term, moderate treadmill exercise on hippocampal plasticity. This effect was in general independent of transcriptional processes and of BDNF upregulation, and occurred even in the presence of increased corticosterone levels.

Morphological Adjustments of the Radial Nerve Are Intensity-Dependent

“…Adaptation of intra cellular proteins seemed to follow the increase in the diameter of the nerve fibers. This result is consistent with Ferreira et al 31 who observed that training increased the amount of neurofilament in central nervous axon of rats. The increased density of neurofilaments in GF2 group is consistent with the increase in the area and diameters of myelinated axons observed in this group, since neurofilaments are considered determinants of axon caliber.…”

Exercise as a pro-cognitive, pro-neurogenic and anti-inflammatory intervention in transgenic mouse models of Alzheimer’s disease

“…Three days of wheel running increased numbers of Ki67 + proliferating cells in the rat DG (Patten et al, 2013), while in mice, three days of wheel running increased doublecortin (DCX) + newly-born neurons (Brandt et al, 2010) and cell proliferation and survival (Kronenberg et al, 2006). Forced treadmill exercise also has pro-neurogenic effects; exercise-induced increases in cell proliferation, neuronal differentiation and cell survival have all been reported in mice and rats trained on treadmill exercise protocols Ferreira et al, 2011;Glasper et al, 2010). Regardless of exercise modality, additional structural measures have been reported to be modulated by exercise.…”

Effects of Voluntary Physical Exercise, Citicoline, and Combined Treatment on Object Recognition Memory, Neurogenesis, and Neuroprotection after Traumatic Brain Injury in Rats

“…26 The first injection was given on day 11 of the exercise/sedentary condition. This moment of administration was chosen because cell proliferation increases induced by exercise seem to peak during the second week of treatment 27 as well as to minimize any interference with a possible increase in proliferation due to TBI. 28 …”