title: Inhibition of angiogenesis, fibrosis and thrombosis by tetramethylpyrazine: mechanisms contributing to the SDF-1/CXCR4 axis.
abstract: BACKGROUND
  Tetramethylpyrazine (TMP) is one of the active ingredients extracted from the Chinese herb Chuanxiong, which has been used to treat cerebrovascular and cardiovascular diseases, pulmonary diseases and cancer. However, the molecular mechanisms underlying the actions of TMP have not been fully elucidated. In a previous study we showed that TMP-mediated glioma suppression and neural protection involves the inhibition of CXCR4 expression. The SDF-1/CXCR4 axis plays a fundamental role in many physiological and pathological processes. In this study, we further investigated whether the regulation of the SDF-1/CXCR4 pathway is also involved in the TMP-mediated inhibition of neovascularization or fibrosis and improvement of microcirculation.
  
  
  RESULTS
  Using a scratch-wound assay, we demonstrated that TMP significantly suppressed the migration and tubule formation of the human umbilical vein endothelial cell line ECV304 in vitro. The expression of CXCR4 in ECV304 cells is notably down-regulated after TMP treatment. In addition, TMP significantly suppresses corneal neovascularization in a rat model of corneal alkali burn injury. The expression of CXCR4 on days 1, 3 and 7 post-injury was determined through RT-PCR analysis. Consistent with our hypotheses, the expression of CXCR4 in the rat cornea is significantly increased with alkali burn and dramatically down-regulated with TMP treatment. Moreover, TMP treatment significantly attenuates bleomycin-induced rat pulmonary fibrosis, while immunofluorescence shows a notably decreased amount of CXCR4-positive cells in the TMP-treated group. Furthermore, TMP significantly down-regulates the expression of CXCR4 in platelets, lymphocytes and red blood cells. Whole-blood viscosity and platelet aggregation in rats are significantly decreased by TMP treatment.
  
  
  CONCLUSIONS
  These results show that TMP exerts potent effects in inhibiting neovascularization, fibrosis and thrombosis under pathological conditions; thus, the underlying mechanism of TMP might partially contribute to the down-regulation of CXCR4.
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, GuangZhou, GuangDong, P. R. China.
authors: Xiaoxiao
authors: X
authors: Cai
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, GuangZhou, GuangDong, P. R. China.
authors: Zhao
authors: Z
authors: Chen
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, GuangZhou, GuangDong, P. R. China.
authors: Xueke
authors: X
authors: Pan
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, GuangZhou, GuangDong, P. R. China.
authors: Lei
authors: L
authors: Xia
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, GuangZhou, GuangDong, P. R. China.
authors: Pei
authors: P
authors: Chen
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, GuangZhou, GuangDong, P. R. China.
authors: Ying
authors: Y
authors: Yang
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, GuangZhou, GuangDong, P. R. China.
authors: Huan
authors: H
authors: Hu
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, GuangZhou, GuangDong, P. R. China.
authors: Jing
authors: J
authors: Zhang
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, GuangZhou, GuangDong, P. R. China.
authors: Kaijing
authors: K
authors: Li
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, GuangZhou, GuangDong, P. R. China.
authors: Jian
authors: J
authors: Ge
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, GuangZhou, GuangDong, P. R. China.
authors: Keming
authors: K
authors: Yu
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, GuangZhou, GuangDong, P. R. China.
authors: Jing
authors: J
authors: Zhuang
mesh_terms: D020533:Angiogenesis Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D054377:Chemokine CXCL12 / Q000032:analysis / Q000378:metabolism*; D003315:Cornea / Q000098:blood supply / Q000187:drug effects / Q000473:pathology; D006801:Humans; D008168:Lung / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D011658:Pulmonary Fibrosis / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D011719:Pyrazines / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019718:Receptors, CXCR4 / Q000032:analysis / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013927:Thrombosis / Q000188:drug therapy* / Q000378:metabolism
chemical_list: D020533:Angiogenesis Inhibitors; D054377:Chemokine CXCL12; D010975:Platelet Aggregation Inhibitors; D011719:Pyrazines; D019718:Receptors, CXCR4; C017953:tetramethylpyrazine