Artikel
In-vivo-detection of in vitro cultivated autologous chondrocytes
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Veröffentlicht: | 8. August 2007 |
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Introduction: The aim of our research is to improve the biocompatibility of implants made from porous polyethylene by covering with autologous chondrocytes. Until now, it is not clear, in what way in-vitro cultivated cells become integrated in vivo. To find out, how the inserted autologous cells remain in their natural environment, it is essential to distinguish these cells from the surrounding tissue. Therefore, we labeled the cells with iron-nano-particles for detecting them by MRI-technology in vivo. For histological analysis, the cells were labeled with a fluorescence marker additionally.
Methods: We choose the guinea pig as animal model. Cartilage was taken from the concha, chondrocytes were isolated and cultivated. Before seeding the cells onto the polyethylene, labeling was done by mixing the cells with two different markers: ENDOREM® and fluidMAG®. After two further weeks in vitro-culture, the specimens were incubated with a fluorescence marker for 48 hours. We choose the frontal scull of the donor-animals for implantation of the specimens. Unlabeled cell-seeded samples were implanted as a control.
MRI investigations were done1 week, as well as 1, 2 and 4 months after implantation. After 2 or 4 month the specimens with the surrounding tissue were removed for histological examination.
Results: The presence of Iron-particles caused a signal intensity reduction in MRI. In contrast the identification of the unlabeled control was more difficult. The follow-up during 4 months showed a nearly unchanged intensity of the MRI-signals. The histological examinations revealed the presence of iron-labeled cells near the implant independent from the label and retention-time of the implants. The iron-nano-particles were incorporated into the cells. But the distribution of the labeled cells in the surrounding of the implant was inhomogeneous.
The fluorescence signal was detectable after 2 months in histological sections, but only very weak after 4 months.
Conclusions: Chondrocytes tolerate a labeling with iron-nano-particles and a fluorescence marker.
Labeling with iron-nano-particles was a qualified method to detect in vitro cultivated autologous cells in their natural environment in vivo by MRI up to four months.
Labeling with iron-nano-particles allows to distinguish the inserted cells from their environment by histological staining.
The fluorescence-signal was detectable after 2 month only.