Chinese Journal of Tissue Engineering Research ›› 2013, Vol. 17 ›› Issue (41): 7205-7212.doi: 10.3969/j.issn.2095-4344.2013.41.004

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Mechanism of osteoblast apoptosis induced by dexamethasone via the protein kinase C pathway

Zhong Xing1, Zhang De-zhi2, Han Hong-bin3, Li Kai4, Yang Zhi-yang1, Fu Wen-ju1   

  1. 1Liaoning Medical University, Jinzhou  121001, Liaoning Province, China; 2Department of Orthopedics, the First Affiliated Hospital of Liaoning Medical University, Jinzhou  121001, Liaoning Province, China; 3Department of Scientific Research, Peking University Health Science Center, Beijing  100191, China; 4Peking University Health Science Center, Beijing  100191, China
  • Received:2013-01-03 Revised:2013-01-28 Online:2013-10-08 Published:2013-11-01
  • Contact: Zhang De-zhi, M.D., Associate chief physician, Department of Orthopedics, the First Affiliated Hospital of Liaoning Medical University, Jinzhou 121001, Liaoning Province, China zdzhi5@yahoo.com.cn
  • About author:Zhong Xing★, Studying for master’s degree, Liaoning Medical University, Jinzhou 121001, Liaoning Province, China baobeilongdao@163.com

Abstract:

BACKGROUND: Dexamethasone can improve the cell apoptosis and decrease the number of osteoblasts and bone cells through increasing the time of cell cycle. Protein kinase C is a kind of intraecellular singnal transduction pathways, and there are related reports on the relationship between protein kinase C and cell apoptosis.
OBJECTIVE: To investigate the mechanism of dexamethasone-induced osteoblast apoptosis via protein kinase C intracellular signal transduction pathway.
METHODS: Fetal rat bone marrow mesenchymal stem cells were collected for osteogenic induction, and the cells were divided into dexamethasone group, phorbol group and star cytochalasin group. The cells in the dexamethasone group were added with 1×10-6 mol/L dexamethasone, the cells in the phorbol group were added with 1×10-6 mol/L dexamethasone and 1×10-7 mol/L phorbol, while the cells in the star cytochalasin group were added with 1×10-6 mol/L dexamethasone and 1×10-7 mol/L star cytochalasin. The proliferation and inhibition of the cells in different intervention groups were observed, and the content of protein kinase C in the cell membrane and cytoplasm was measured.
RESULTS AND CONCLUSION: Dexamethasone could induce apoptosis significantly, and after added with phorbol, the apoptosis was increased significantly; while after added with star cytochalasin, the apoptosis was decreased significantly. After added with dexamethasone, the content of protein kinase C in the cytoplasm was significantly decreased, while increased in the cell membrane. At different time points after added with dexamethasone, the change of the content of protein kinase C in the cytoplasm and cell membrane was most significant at 30 minutes. The results indicated that mechanism of dexamethasone-induced osteoblast apoptosis was correlated with protein kinase C, and dexamethasone was the agonist of protein kinase C. After the cells were stimulated, the protein kinase C in the cytoplasm will moved to the cell membrane, and then the content of protein kinase C in the cytoplasm was decreased, while increased in the cell membrane.

Key words: osteoblasts, dexamethasone, bone and bones, protein kinase

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