Effects of shear stress on wound-healing angiogenesis in the rabbit ear chamber.
Recent studies indicate that wall shear stress plays a significant role in the physiological adaptation of the vascular system. This study focused on the effect of sustained wall shear stress on wound-healing angiogenesis by exploring the morphologic and hemodynamic changes in developing microvessels in vivo through the tissue repair process. Rabbits were treated with the alpha 1 blocker prazosin (50 mg/L in water) orally from Day 0 to Day 23 after implantation of ear chambers to increase peripheral blood flow. The microvasculature in the chamber was recorded from Day 7 to Day 23 by using an intravital videomicroscope. The relative area of the chamber covered by vascularized tissue (%), the rate of ingrowth (mm2/day), the total vascular area (mm2), and the wall shear stress level (dyne/cm2) in venules (diameter in 20-40 microns) were quantified using a computerized image analysis system. The relative area increased significantly in the prazosin-treated animals from Days 7 to 19. The chamber of the treated group was completely covered with vascularized tissue earlier than that of the control group. The final total vascular area was larger by 21% in the treated group. The time course of shear stress in the treated group showed an initial elevation (1.44 times increase vs the control) followed by a gradual decrease toward the control level. These findings suggest that wound-healing angiogenesis may be partly involved in the adaptive response of microvasculature to shear stress.
Ichioka
S
S
Department of Plastic Surgery, Faculty of Medicine, University of Tokyo, Japan.
Shibata
M
M
Kosaki
K
K
Sato
Y
Y
Harii
K
K
Kamiya
A
A
D000317:Adrenergic alpha-Antagonists / Q000097:blood / Q000494:pharmacology; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D004423:Ear / Q000098:blood supply / Q000601:surgery*; D004730:Endothelium, Vascular / Q000166:cytology; D008297:Male; D018919:Neovascularization, Physiologic / Q000502:physiology*; D011224:Prazosin / Q000097:blood / Q000494:pharmacology; D019736:Prostheses and Implants; D011817:Rabbits; D013314:Stress, Mechanical; D014699:Venules / Q000503:physiopathology; D014945:Wound Healing / Q000502:physiology*
D000317:Adrenergic alpha-Antagonists; D011224:Prazosin