Expression of Tie-2 and angiopoietin-1 and -2 in early phase of ulcer healing.
BACKGROUND
Angiogenesis is an important process in tissue development and wound healing. The Tie-2 receptor tyrosine kinases and ligands, angiopoietin (Ang)-1 and -2 have been postulated to play key roles in vascular development. The purpose of this study was to evaluate the expression of Tie-2 and Ang-1 and -2 in an acetic acid-induced gastric ulcer healing process in rats.


METHODS
Gastric specimens were obtained at 0 (control), 1, 3, 5, 7, and 14 days after ulcer induction for reverse transcription polymerase chain reaction (RT-PCR), Western blot analysis, and immunohistochemical analysis.


RESULTS
Expression of Tie-2 and Ang-1 and -2 mRNAs was detected in normal gastric tissue and ulcerative tissues by RT-PCR. Western blot analysis revealed that Tie-2 expression reached a maximum on the third to fifth days. Expression of Ang-1 and -2 peaked on the first day. Ang-1 expression gradually became weaker in 2 weeks, whereas Ang-2 expression returned to normal in a few days. Immunohistochemically, Tie-2 was expressed constitutively in the endothelial cells of pre-existing vessels of the gastric wall, and Tie-2 expression was increased in the new capillaries of the ulcer base.


CONCLUSIONS
These findings suggest that Tie-2 and Ang-1 and -2 play an important role in angiogenesis in the early phase of ulcer healing.
Wen
Chun Yang
CY
Department of Molecular Pathology, Atomic Bomb Disease Institute, Nagasaki University School of Medicine, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
Ito
Masahiro
M
Chen
Long-Dian
LD
Matsuu
Mutsumi
M
Shichijo
Kazuko
K
Nakayama
Toshiyuki
T
Nakashima
Masahiro
M
Xu
Zhao-Min
ZM
Ohtsuru
Akira
A
Hsu
Chao-Tien
CT
Sekine
Ichiro
I
D043925:Angiogenesis Inducing Agents / Q000378:metabolism*; D042683:Angiopoietin-1; D042702:Angiopoietin-2; D000818:Animals; D015153:Blotting, Western; D007150:Immunohistochemistry; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D042787:Receptor, TIE-2; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014945:Wound Healing / Q000502:physiology*
D043925:Angiogenesis Inducing Agents; D042683:Angiopoietin-1; D042702:Angiopoietin-2; C467629:Angpt1 protein, rat; D008562:Membrane Glycoproteins; D020794:Receptor Protein-Tyrosine Kinases; D042787:Receptor, TIE-2