Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Weber, K.
Effects of Immobilization on Bone Physiology and Metabolism
Humanmedizin; [ Diplomarbeit ] Medical University of Graz; 2014. pp. 103
[OPEN ACCESS]
FullText
- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Goswami Nandu
- Holzer Lukas
- Altmetrics:
- Abstract:
- Introduction: Bone is underlying a constant process of remodelling, adapting to inner and outer mechanical forces. Physical loading is an essential determinant for the maintenance of a physiological bone quality. Bone is known to response fast in terms of mechanical unloading. As a result, deconditioning with a loss of bone mass and reduction of bone density will set in quickly. Bone metabolism is not fully understood on a molecular biological level. Therefore, this diploma thesis will provide an overview of bone biology and physiology. Further, the effects of a 21 days bed rest trial on the molecular mechanisms of bone metabolism will be investigated. Methodology: 12 study subjects were exposed to bed rest for 21 days with a 6° head-down-tilt position. 3 groups were set up, respectively: Bed rest (BR), bed rest plus exercise (BR + EX), bed rest plus exercise plus diet (BR + EX + Diet). Each of the 12 volunteers acted as their own control and changed their allocated group during each campaign. Due to cost issues, only 3 subjects from each group of the first campaign (n=4) were chosen randomly for investigation of the molecular mechanisms associated with bed rest, with and without exercise and nutrition interventions. Blood samples were taken before and at campaign end. Total mRNA was extracted to generate cRNA, which was hybridized on microarray slides. Biological analysis and interpretation were performed with GeneSpring and Ingenuity Pathway Analysis (IPA). Results: Using IPA a list of 233 genes related to “Skeletal and muscular system development and function” was constructed, which mapped back to 409 probes. After applying a threshold of FC = 1,5 15 genes of the BR, 33 genes of the BR + EX and 16 genes of the BR + EX + Diet group were sorted out. For a better biological understanding and interpretation, the 15 genes of the BR group were compared to those of the treatment groups (BR + EX, BR + EX + Diet) based on their expression values and polarity. Discussion: We identified differences in gene expression changes based on the type of intervention using the innovative technique of transcriptomics. Differentially expressed genes in the BR group are reported to play an important role in bone metabolism and mechanotransduction. We conclude that microarray analysis of blood samples is an appropriate technique to investigate early biological changes due to bed rest on a molecular level.