Abstract: BACKGROUND: The research group has found that the small molecule peptides of antler gum are rich in peptide chains that promote bone growth, proliferation and ossification of bone marrow mesenchymal stem cells. The specific mechanism and target of antler glue in the treatment of avascular necrosis of the femoral head are still unclear, which needs further studies.
OBJECTIVE: To explore the mechanism of antler glue in the treatment of femoral head necrosis based on proteomics.
METHODS: Thirty-six female Wistar rats, SPF grade, were randomized into a blank group, a model group, and an antler glue group. The rats in the latter two groups were given retinoic acid 70 mg/kg once a day for 8 weeks to establish a rat model of femoral head necrosis, while the rats in the blank group were not treated. At 8 weeks after modeling, the rats in the antler glue group were given antler glue 0.35 g/kg, and those in the model and blank groups were given the same volume of 0.9% sodium chloride solution, once a day by gavage for 8 weeks. Pathological examination of bone tissue was used for verifying the successful modeling and the repair effect of antler glue on the femoral head. Non-standard (Label-free) proteome quantification technology was used to detect differential genes among groups. Biological function of differential proteins and signaling pathways involved were enriched based on GO and KEGG database analyses. STRING database was used to construct the target protein-protein interaction network diagram. The study protocol was approved by the Animal Experiment Ethics Committee of Shandong Academy of Traditional Chinese Medicine.
RESULTS AND CONCLUSION: The pathological sections of bone tissue showed that antler glue could effectively repair the necrotic femoral head. A total of 1 457 kinds of proteins were identified, including 353 kinds of common differential proteins between blank group and model group as well as between model group and antler glue group. In the model group, 97 kinds of differential proteins that increased or decreased showed a significant callback after intervention with antler glue. The mechanism of antler glue in the treatment of femoral head necrosis involves blood circulation, energy metabolism, inflammatory reaction and immune process. Protein disulfide isomerase (P4HB), cadherin 2 (CDH2), annexin A2 (ANXA2), proprotein convertase subtilisin/kexin type 9 (PCSK9), milk fat globule epidermal growth factor 8 (MFGE8), and bone morphogenetic protein may be important targets of antler glue. Antler glue may treat femoral head necrosis by regulating transforming growth factor β, glycolysis/gluconeogenesis, and PI3K-Akt signaling pathways.

Key words: antler glue, serum, proteomics, liquid chromatography-mass spectrometry, femoral head necrosis, differential protein, KEGG pathway analysis, transforming growth factor β