The Notch Signaling System Is Involved in the Regulation of Reparative Angiogenesis in the Zone of Stasis.
The Notch pathway ligand Delta-like 4 (Dll4) functions as an antiangiogenic factor, inhibiting vascular endothelial growth factor (VEGF)-induced angiogenesis. This function is documented in tumor and embryonic vasculature. However, its implication in burn wounds remains unexplored. Our objective was to explore the involvement of the Notch in the healing of zone of stasis burns. We hypothesized that anti-Dll4 therapy would prevent progressive necrosis in the stasis zone by promoting angiogenesis. Burns were created in 21 rats using the comb burn model. The Notch inhibitor N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-phenylglycine-t-butyl-ester was administered in the treatment group. Controls were given the same amount of solvent. Seven days after the burn, skin samples were evaluated for VEGF and Dll4 gene expressions. Immunohistochemical analysis was used for the assessment of vascular density, endothelial Dll4 expression, and apoptosis count. Histologic grading of tissue damage was performed. Circulating levels of VEGF and Dll4 were determined. VEGF and Dll4 mRNA levels were found to be simultaneously induced after the burn. In the treatment group, a significant increase in the number of vessels was observed. However, gross evaluation documented an expansion of necrosis to the zone of stasis with marked activation of apoptosis. Histologic assessment showed that the resultant vascular overgrowth was accompanied by extensive edema and abundant infiltration of leukocytes. We provide evidence for the involvement of Notch in the regulation of angiogenesis in zone of stasis burns.
From the *Department of Plastic, Reconstructive and Aesthetic Surgery, and †Department of Histology and Embryology, Faculty of Medicine, Ahi Evran University, Kirşehir, Turkey; ‡Department of Medical Genetics, Faculty of Medicine, Başkent University, Ankara, Turkey; and §Department of Pharmacology and ‖Department of Biochemistry, Faculty of Medicine, Ahi Evran University, Kirşehir, Turkey.
Ozan Luay
OL
Abbas
Orhan
O
Özatik
Yunus Kasim
YK
Terzi
Fikriye Yasemin
FY
Özatik
Rukiye
R
Nar
Gamze
G
Turna
D000818:Animals; D002056:Burns / Q000473:pathology / Q000503:physiopathology*; D004151:Dipeptides / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors; D008297:Male; D008565:Membrane Proteins / Q000037:antagonists & inhibitors; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D051880:Receptors, Notch / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D014945:Wound Healing / Q000187:drug effects / Q000502:physiology*
D004151:Dipeptides; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C419410:N-(N-(3,5-difluorophenacetyl)alanyl)phenylglycine tert-butyl ester; D051880:Receptors, Notch; C064045:delta protein