[The effects of nitric oxide on the survival of a random pattern skin flap].
OBJECTIVE
To observe the effect of nitric oxide (NO) on the survival of a random pattern skin flap.


METHODS
Caudal based random skin flaps (9 cm x 3 cm) were raised on the back of Wistar rats. Six methods were used in the experiment to observe the effect of NO synthase inhibitor L-NAME and NO synthase substrate L-arginine on flaps: image analysis technology; light and electron microscopic studies; enzyme histochemistry of NOS in flaps; concentration of NO2-/NO3- in plasma and wet/dry ratio of the flap tissue.


RESULTS
Survival area of flap in the L-arginine-treated group significantly increased (67.06 +/- 5.65)% (p < 0.01) whereas the area in the L-NAME-treated group significantly decreased (35.17 +/- 1.87)% (p < 0.01) compared with the control group (53.25 +/- 3.24)% at seven days after the operation. General and microscopic observations showed that pathological changes in the L-arginine-treated group were fewer. Abundant capillaries and fewer inflammatory cells were noticed in the L-arginine-treated group. Transmission Electron Microscopy (TEM) studies find endothelial swelling, thrombosis-formation and endothelial loss of contact with the basement membrane in the L-NAME treated group. Before operation, the serum NO concentrations were not significantly different in three groups (p > 0.05). After operation, NO concentration of the control group began to increase and reached to the top at the third day. L-Arg kept serum NO concentration in a higher level than the control. Enzyme histochemistry of NOS in flaps: microvessel intima in dermis, hair follicles, sweat glands and inflammatory cells showed oxford blue, more positive in flaps of the L-Arg treated group than the control group at the third day after operation. The flaps of L-NAME-treated group demonstrated negative or weak positive. Wet/dry ratio: twenty-four hours after flap elevation wet/dry weight ratios increased significantly in all regions of the flap of the L-arginine-treated rats compared with saline-treated rats. The ratios of the flaps of L-NAME-treated rats were reduced compared with saline-treated rats.


CONCLUSIONS
NO could improve microcirculation of the flap and increase its survival rates. The mechanism might be that NO could accelerate flap vascularization and protect flaps from ischemia-reperfusion injury.
Du
Jiamei
J
Gongren Hospital, Hebei, Tangshan 063000, China.
Jin
Jianxue
J
Zhang
Songlin
S
Tao
Zhilu
Z
Cheng
Aiguo
A
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D062109:Dermatologic Surgical Procedures; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006085:Graft Survival / Q000187:drug effects; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009566:Nitrates / Q000097:blood; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D009573:Nitrites / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D012867:Skin / Q000201:enzymology / Q000648:ultrastructure; D016038:Skin Transplantation; D013524:Surgical Flaps / Q000502:physiology*
D004791:Enzyme Inhibitors; D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester