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Hypothesis. Exercise and antidepressants independently increase hippocampus (BDNF) and neurogenesis.Effects are on BDNF synergistic . Background Information. Brain-derived neurotrophic factor (BDNF) is capable of mediating the beneficial effects of exercise on brain plasticity, supports the health
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1. Wheel Running and Fluoxetine Antidepressant Treatment Have Differential Effects in the Hippocampus and the Spinal Cord C. Engesser-Cesar, A. J. Anderson, and C. W. Cotman
2. Hypothesis Exercise and antidepressants independently increase hippocampus (BDNF) and neurogenesis.
Effects are on BDNF synergistic
3. Background Information Brain-derived neurotrophic factor (BDNF) is capable of mediating the beneficial effects of exercise on brain plasticity, supports the health and functioning of glutamatergic neurons, promotes differentiation, neurite (process) extension, and the survival of a variety of neuronal populations (1).
4. Exercise Improves Various neurological conditions
Age-related neurodegeneration
Depression
Alzheimers disease
Traumatic brain injury
Spinal cord injury
5. Animals C57BL/10 female mice (n=112)
2 months old
Acclimatized for 1 week, 7 days of antibiotic admin
Excluded for difficulty with wheel running
Food and water ad libitum
12h light/dark cycle
Randomly assigned
6. Animals
7. Methods and Materials
8. Methods and Materials 21 days of fluoxetine treatment
With or without wheel running
Daily i.p. injections
6 animals from each group got BrdU injections on final 7 days
Killed 24h after last fluoxetine injection
Staggered over 4 days (estrous)
9. Fluoxetine Decreased running distance
High dose group ran significantly less by the end of the experiment
Increased weight gain
10. Exercise and Fluoxetine Together, increase cell proliferation and survival in the hippocampus
IGF-1: positively linked to hippocampal neurogenesis
Seen with: Exercise-mediated recovery from traumatic brain injury
Fluoxetine administration
BDNF: positively linked to hippocampal neurogenesis
is activated more rapidly when used in combination
with exercise and antidepressants (Cotman 2002)
11. Spinal Cord Examined rostral, thoracic, lumbar
Spinal cord IGF-1 protein did not change with wheel running, and decreased with fluoxetine (high dose)
Cytogenesis also decreased with fluoxetine (dose dependent)
BDNF did not change in rostral or lumbar after running or fluoxetine treatment
Wheel running and fluoxetine did not protect against spinal cord injury
12. Rostral Cord
13. Lumbar Cord
14. Thoracic Cord
15. Effects of exercise and fluoxetine on spinal cord IGF-1 protein significantly decreased with administration of fluoxetine
No neurogenesis
Decreased cytogenesis
16. Spinal Cord Injury No benefit for pre-injury exercise for SCI recovery
Post-injury exercise and/or fluoxetine may be protective (not explored here)
Trophic factors or cytogenesis could be a recovery mechanism
Decreased BrdU in spinal cord ??
17. Results In the hippocampus fluoxetine increases BDNF, cytogenesis, and neurogenesis
Dose dependent
18. Results
BDNF was not induced by exercise
but increased by fluoxetine
Hippocampal IGF-1 protein not affected by fluoxetine, exercise, or both
Fluoxetine decreased IGF-1 protein in all three regions of the spinal cord
19. Results Decreased trend of BrdU positive cells in exercise animals
Fluoxetine also decreases BrdU
Decrease in cell proliferation
BrdU positive means there was neurogenesis present, DCX positive cells means there was cytogenesis presentBrdU positive means there was neurogenesis present, DCX positive cells means there was cytogenesis present
20. BDNF and Serum IGF1 Exercise alone had little effect on increasing BDNFExercise alone had little effect on increasing BDNF
21. IGF1 hippocampal results
22. Neurogenesis and Cytogenesis High dose fluoxetine increases BrdU cells by percentage, and DCX positive cells by percentage, wheel running had little effect on BrdU or DCX cells.High dose fluoxetine increases BrdU cells by percentage, and DCX positive cells by percentage, wheel running had little effect on BrdU or DCX cells.
25. Neurogenesis and cytogenesis results Increased dentate granule cell layer
DCX increases, not BrdU with fluoxetine
Fluoxetine and exercise combined no effect on cytogenesis or neurogenesis
26. Cell numerical density
27. De Foubert Graph Decrease in BDNF after 4 days of running and fluoxetine administration, increase in BDNF after 7 days of running and fluox admin, after 14 days of running and fluox admin large increase in hippocampl BDNF Decrease in BDNF after 4 days of running and fluoxetine administration, increase in BDNF after 7 days of running and fluox admin, after 14 days of running and fluox admin large increase in hippocampl BDNF
28. De Foubert Graph Decrease in BDNF after 4 days of running and fluoxetine administration, increase in BDNF after 7 days of running and fluox admin, after 14 days of running and fluox admin large increase in hippocampl BDNF Decrease in BDNF after 4 days of running and fluoxetine administration, increase in BDNF after 7 days of running and fluox admin, after 14 days of running and fluox admin large increase in hippocampl BDNF
29. De Foubert Graph Decrease in BDNF after 4 days of running and fluoxetine administration, increase in BDNF after 7 days of running and fluox admin, after 14 days of running and fluox admin large increase in hippocampl BDNF Decrease in BDNF after 4 days of running and fluoxetine administration, increase in BDNF after 7 days of running and fluox admin, after 14 days of running and fluox admin large increase in hippocampl BDNF
30. De Foubert results Herein, 21 days of wheel running and fluoxetine administration increased BDNF cells in hippocampus
Dependent on length of treatment
31. Discussion Exercise or fluoxetine did not increase IGF-1 as previously seen
No change in BDNF protein with exercise in female mice
Gender, strain, or amount of exercise could effect BDNF protein
High dose fluoxetine increased hippocampal BDNF protein
32. Discussion Wheel running did not effect BDNF in hippocampus
Exercise and fluoxetine may use different mechanisms for BDNF increase
No change in IGF-1 in hippocampus
High dose fluoxetine increased cytogenesis and neurogenesis in hippocampus
33. Discussion No increase in BDNF in spinal cord
High dose fluoxetine decreased IGF-1
No increase cytogenesis/neurogenesis in spinal cord with any treatment
No pre-injury exercise helped SCI
34. Conclusion Fluoxetine increased BDNF, cytogenesis, and neurogenesis in the hippocampus
Fluoxetine decreased IGF-1 and cytogenesis in the spinal cord
35. References 1. Cotman, C. W., and C. Engesser-Cesar. Exercise enhances and protects brain function. Exerc. Sport Sci Rev. 30:75-79, 2002.
2. De Foubert, G., S. L. Carney, C. S. Robinson, E. J. Destexhe, R. Tomlinson, C. A. Hicks, T. K. Murray, J. P. Gaillard, C. Deville, V. Xhenseval, C. E. Thomas, M. J. ONeill, and T. S. C. Zetterstrom. Fluoxetine-induced change in rat brain expression of brain-derived neurotrophic factor varies depending on length of treatment. J. Neurosci. 128:597-604, 2004
3. van Praag, H., G. Kempermann, and F. H. Gage. Running increases cell proliferation and neurogenesis in the adult mouse dentate gyrus. Nature Neurosci. 2:266-270, 1999