J Korean Soc Plast Reconstr Surg.  1998 Oct;25(7):1266-1275.

Effects of pentoxifylline of the revascularization of the island flap in the diabetic rabbit

• No authors listed

Abstract

The rate at which neovascular blood supply achieves the capability of sustaining survival of the flap, independent of the original vascular supply, has been extensively investigated. However, the exact time and route of neovascularization remains debatable. Evidence emphasizing the importance of revascularization from the bed over that from the wound edges also remains confusing. Diabetes mellitus induces morphologic and functional changes within small blood vessels as well as within the cellular and acellular constituents of bloods ,giving rise to a hyperviscous and hypercoagulable state. Pentoxifyllline lowers blood viscosity effectively and therefore has a salutary effect on the movement of bloods especially within small vessels. This experiment was desinged to investigate the effects of pentoxifylline administration on the revascularization of island flap in alloxan-induced diabetic rabbits. Twenty rabbits were divided into 4 groups: normal group, normal-pentoxifylline treated group, diabetic group, diabetic-pentoxifyllne treated group.The diabetic was maintained under insulin regimens which controlled serum glucose levels between 200 and 300ml/dl. A 10mg/kg of pentoxifylline was administered intraperitoneally twice a day throughout the experimental period. A 3x4cm sized island flap including perichondrium was elevated from the dorsum of rabbit ear 4 weeks after induction of diabetes. The vascular pedicle of the flap was ligated 5 days after the flap elevation. The eryhrocyte deformability, the survival area and vascular network of the flap were examined 7 days after the pedicle ligation.The tissue oxygen pressure was measured at the center of the flap before and after the flap elevation and pedicle ligation. The results were as follows;1.The flap survival of diabetic rabbit was decreased significantly compared with that of rabbit and increased significantly after pentoxifylline treatment(p<0.05). 2.The tissue oxygen pressure (PtiO2) after flap elevation and after pedicle ligation were decreased significantly compared with that before flap elevation in all groups(p<0.05)3. The erythrocyte deformability was decreased significantly in diabetic rabbit and increased significantly after pentoxifylline treatment in normal and diabetic rabbits(p>0.05) 4. In diabetic rabbit, the vascular network was scanty and revascularization was blocked by necrotic tissue around the flap margin. In pentoxifylline treated diabetic rabbit, fine vessels were increased and a few vascular connections at the flap margins and a few perforators from the ventral side were noticed.These results demonstrate that 1)reduced erythrocyte deformability caused by diabetes may reduce the revascularization of island flap.2)the revascularization from the flap margin was mainly affected by diabetes, 3)these can be restored by administration of pentoxifylline.On the basis of this experiment, we recommend the administration of pentoxifylline when anticipating microvacular free flap or island flap procedures in diabetic patients.

MeSH Terms

Blood Glucose
Blood Vessels
Blood Viscosity
Diabetes Mellitus
Ear
Erythrocyte Deformability
Free Tissue Flaps
Humans
Insulin
Ligation
Oxygen
Pentoxifylline*
Rabbits
Wounds and Injuries
Insulin
Oxygen
Pentoxifylline