Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Schauer, A.
In vitro cytocompatibility and gene expression of osteogenic markers in osteoblasts and growth plate chondrocytes after magnesium alloy treatment
[ Diplomarbeit ] Medical University of Graz; 2013. pp. 66
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Weinberg Annelie-Martina
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- Abstract:
- Introduction: Nowadays fracture treatment in children is often done by surgical intervention. This tendency implies per se a high operation rate and an even higher one due to the, for this purpose mainly used, anticorrosive stabilisation items. This is the case because they have to be removed after fracture healing. The reoperation with all its troubles, risks and costs illustrates the advantages and also the necessity for biodegradable materials. Amongst the worldwide tested different degradable materials are also bioresorbable magnesium alloys. In this study two different alloys, ZX50 and WZ21 are tested in vitro in terms of their osteoinductivity and their cytocompatibility. Considering the alloys as possible materials for fracture stabilisation in paediatric surgery, more precisely in the growing bone, tests on an osteoblast cell line and on human growth plate chondrocytes are required. Methods: For testing the osteoinductivity the MG63 cell line and the human growth plate chondrocytes were treated with the prior prepared eluates of the alloys. Treatment with pure SBF was to assess the influence of the vehicle while untreated cells served as control. After 48 hours mRNA of the samples was harvested and transcribed into cDNA. QRT-PCR was used to determine expression changes of the osteoinductive genes alkaline phosphatase and osteocalcin compared to the housekeeping gene GAPDH. To investigate cytocompatibility, namely metabolic activity and viability in different eluate concentrations, MTT and neutral red testing was performed. The MTT method is based on a conversion, the neutral red method on a colour up-take into the cells. The measurement of the optical density was conducted on a spectrometer at a wavelength of 550 nm and set into relation with the data of SBF and untreated cells, respectively. Results: The 48 hours treatment of the hGPC with the ZX50 and the WZ21 eluate showed a significant alteration in both investigated genes. The treatment of the MG63 osteoblasts revealed an augmentation of alkaline phosphatase and osteocalcin only with the ZX50 eluate. The gene expression was compared to the levels of untreated and SBF treated cells. The cytocompatibility of the two eluates and of the two cell types diverged. While the WZ21 eluate neither influenced viability nor metabolic activity throughout the tested concentration range, the ZX50 eluate treatment decreased viability and metabolic activity in both cell types. This decrease set in at a lower concentration for the hGPC than for the MG63 cells. Discussion: Both tested alloys showed good cytocompatibility and an augmentation of osteoinductive markers. The ZX50 alloy appeared to be less cytocompatible than WZ21. This could be due to its faster degradation and the additional stronger increase in pH-number.