Abstract: BACKGROUND: Our previous studies found that the polypeptide of Cornus cervi Colla can promote bone growth, which has a good application prospect in the treatment of bone diseases. However, how Cornus cervi Colla works in the body and the principle are not clear.
OBJECTIVE: To study the in vivo distribution and tracing of Cornus cervi Colla using fluorescence labeling and tracer technique.
METHODS: Cornus cervi Colla was fluorescently labeled using fluorescein isothiocyanate, and the labeling results were detected by fluorescence imaging and UV spectral scanning. Successfully labeled Cornus cervi Colla was injected into mice by gavage, and the absorption of Cornus cervi Colla into blood was detected by laser confocal microscopy, and the distribution of Cornus cervi Colla in mice was detected by small animal in vivo imager. The distribution of Cornus cervi Colla in the mice was detected by laser confocal microscopy. Samples were taken from serum and bone at the time of the strongest fluorescence, and gel electrophoresis was carried out on serum and bone tissue protein solutions, and the components of Cornus cervi Colla absorbed into target organs were determined by secondary mass spectrometry.
RESULTS AND CONCLUSION: The fluorescent markers were successfully separated by dextran gel chromatography, and the fluorescence imaging and ultraviolet spectrum scanning proved that the labeling was successful, and the fluorescence substitution degree of FITC-labeled Cornus cervi Colla was 0.953%. The fluorescence intensity of the components of Cornus cervi Colla in the blood showed that Cornus cervi Colla was most distributed in serum after oral administration for 2 hours. The fluorescence images of mice at different times were the same as those of bilateral femur and tibia, indicating that Cornus cervi Colla could play a role by entering the bone. Compared with UniProt database, secondary mass spectrometry showed that the peptide was a characteristic fragment of decorin. It is proved that decorin in Cornus cervi Colla can enter the bone to play a therapeutic role.

Key words: Cornus cervi Colla, fluorescent tracer, components that enter the blood, components that enter the bone, decorin