Objective To evaluate the influence of PKH26 labeling on the biological function of the goat nucleus pulposus cells and the biological function of seeded cells in nude mice by in vivo imaging techonology. Methods Primary nucleus pulposus cells were isolated by enzymatic digestion from the nucleus pulposus tissue of the 1-year-old goat disc. The nucleus pulposus cells at passage 1 were labeled with PKH26 and the fluorescent intensity was observed under the fluorescence microscopy. The labeled cells were stained with toluidine blue and collagen type II immunocytochemistry. The cells viability and proliferation characteristics were assessed by trypan blue staining and MTT assay, respectively. Real-time fluorescent quantitative PCR was used to detect the gene expressions of collagen types I and II, and aggrecan. The fluorescent intensity and scope of the nucleus pulposus cells-scaffold composite in vivo for 6 weeks after implanting into 5 6-week-old male nude mice were measured by in vivo imaging technology. Results Primary nucleus pulposus cells were ovoid in cell shape, showing cluster growth, and the cells at passage 1 showed chondrocyte-like morphology under the inverted phase contrast microscope. The results of toluidine blue and collagen type II immunocytochemistry staining for nucleus pulposus cells at passage 1 were positive. The fluorescent intensity was even after labeling, and the cell viability was more than 95% before and after PKH26 labeling. There was no significant difference in cell growth curve between before and after labeling (P gt; 0.05). The real-time fluorescent quantitative PCR showed that there was no significant difference in gene expressions of collagen types I and II, and aggrecan between before and after labeling (P gt; 0.05). Strong fluorescence in nucleus pulposus cells-scaffold composite was detected and by in vivo imaging technology. Conclusion The PKH26 labeling has no effect on the activity, proliferation, and cell phenotype gene expression of the nucleus pulposus cells. A combination of PKH26 labeling and in vivo imaging technology can track the biological behavior of the cells in vivo.
Objective To review the in vivo imaging research progress of two-photon microscopy (TPM) in spinal cord. Methods The recent literature concerning in vivo two-photon imaging of axon, microglia, and calcium in transgenic mice spinal cord was extensively consulted and reviewed. Results In vivo two-photon imaging of spinal cord provide dynamic information about axonal degeneration and regeneration, microglial accumulation, and calcium influx after spinal cord injury. Conclusion TPM in vivo imaging study on spinal cord will provide theoretical foundation for pathophysiologic process of spinal cord injury.