Document Type : Original Article


1 Department of Anatomical Sciences, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran

2 Neurosciences Research Center, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran


Skin flap necrosis has been remained as an unsolved problem in plastic and reconstructive surgeries. Here, we explored the effects of metformin post-treatment on random skin flap survival in rats. An 8.00 × 2.00 cm dorsal skin flap was created in 24 rats and they were then divided into three groups (n = 8) including Control, metformin (Met) 50.00 mg kg-1 and Met 100 mg kg-1. All animals were administrated orally until seven days after flap surgery. Flap survival, the number of blood vessels and mast cells in the flap tissues were analyzed. Vascular endothelial growth factor (VEGF) expression levels in flap tissues was also determined using immunohistochemical methods. The percentage of survival area in Met 50.00 mg kg-1 and Met 100 mg kg-1 groups were significantly higher compared to control. The blood vessel density and the VEGF positive cells in the viable areas of flaps showed a significant increase in Met 50.00 mg kg-1 group compared to control group. The results of this study suggested that treatment with metformin, especially with low dose following skin flap surgery was effective in improving the flap survival and increasing the neovascularization in the flaps tissues of rats.


  1. Cury V, Moretti AI, Assis L, et al. Low level laser therapy increases angiogenesis in a model of ischemic skin flap in rats mediated by VEGF, HIF-1α and MMP-2. J Photochem Photobiol B 2013; 125: 164-170.
  2. Lu F, Mizuno H, Uysal CA, et al. Improved viability of random pattern skin flaps through the use of adipose-derived stem cells. Plast Reconstr Surg 2008; 121(1): 50-58.
  3. Chen L, Zhou K, Chen H, et al. Calcitriol promotes survival of experimental random pattern flap via activation of autophagy. Am J Transl Res 2017; 9(8): 3642-3653.
  4. Stell PM. Proceedings: The influence of retraction on the viability of a skin flap. Br J Surg 1976; 63(8): 669.
  5. Dölen UC, Sungur N, Koca G, et al. The vasodilator effect of a cream containing 10% menthol and 15% methyl salicylate on random-pattern skin flaps in rats. Arch Plast Surg 2015; 42(6): 695-703.
  6. Gould DJ, Hunt KK, Liu J, et al. Impact of surgical techniques, biomaterials, and patient variables on rate of nipple necrosis after nipple-sparing mastectomy. Plast Reconstr Surg 2013; 132(3): 330e-338e
  7. Yang M, Sheng L, Li H, et al. Improvement of the skin flap survival with the bone marrow‐derived mononuclear cells transplantation in a rat model. Microsurgery 2010; 30(4): 275-281.
  8. Wang WZ, Baynosa RC, Zamboni WA. Update on ischemia-reperfusion injury for the plastic surgeon: 2011. Plast Reconstr Surg 2011; 128(6): 685e-692e.
  9. Baldan CS, Masson IF, Esteves Júnior I, et al. Inhibitory effects of low-level laser therapy on skin-flap survival in a rat model. Plast Surg (Oakv) 2015; 23(1): 35-39.
  10. Karimipour M, Amanzade V, Jabbari N, et al. Effects of gamma-low dose irradiation on skin flap survival in rats. Phys Med 2017; 40: 104-109.
  11. Rinker B, Fink BF, Barry NG, et al. The effect of calcium channel blockers on smoking-induced skin flap necrosis. Plast Reconstr Surg 2010; 125(3): 866-871.
  12. Chen W, Yang D, Wang P, et al. Microencapsulated myoblasts transduced by the vascular endothelial growth factor (VEGF) gene for the ischemic skin flap. Aesthetic Plast Surg 2011; 35(3): 326-332.
  13. Akgül GG, Yenidogan E, Gülçelik MA, et al. Effects of N-acetylcysteine on random skin flaps in rats. Wounds 2013; 25(3): 68-74.
  14. Mamputu JC, Wiernsperger NF, Renier G. Antiatherogenic properties of metformin: the experimental evidence. Diabetes Metab 2003; 29(4 Pt 2): 6S71-6S76.
  15. Hundal RS, Krssak M, Dufour S, et al. Mechanism by which metformin reduces glucose production in type 2 diabetes. Diabetes 2000; 49(12): 2063-2069.
  16. Tian R, Musi N, D’Agostino J, et al. Increased adenosine monophosphate–activated protein kinase activity in rat hearts with pressure-overload hypertrophy. Circulation 2001; 104(14): 1664-1669.
  17. Salminen A, Kaarniranta K, Haapasalo A, et al. AMP‐ activated protein kinase: a potential player in Alzheimer’s disease. J Neurochem 2011; 118(4):
  18. Ashabi G, Khalaj L, Khodagholi F, et al. Pre-treatment with metformin activates Nrf2 antioxidant pathways and inhibits inflammatory responses through induction of AMPK after transient global cerebral ischemia. Metab Brain Dis 2015; 30(3): 747-754.
  19. Yu JW, Deng YP, Han X, et al. Metformin improves the angiogenic functions of endothelial progenitor cells via activating AMPK/eNOS pathway in diabetic mice. Cardiovasc Diabetol 2016; 15: 88. doi:10.1186/ s12933-016-0408-3.
  20. Zhao P, Sui BD, Liu N, et al. Anti‐aging pharmacology in cutaneous wound healing: effects of metformin, resveratrol, and rapamycin by local application. Aging Cell 2017; 16(5): 1083-1093.
  21. Han X, Tao Y, Deng Y, et al. Metformin accelerates wound healing in type 2 diabetic db/db mice. Mol Med Rep 2017; 16(6): 8691-8698.
  22. Taleb S, Moghaddas P, Rahimi Balaei M, et al. Metformin improves skin flap survival through nitric oxide system. J Surg Res 2014; 192(2): 686-691.
  23. Wu H, Ding J, Li S, et al. Metformin promotes the survival of random-pattern skin flaps by inducing autophagy via the AMPK-mTOR-TFEB signaling pathway. Int J Biol Sci 2019; 15(2): 325-340.
  24. Soraya H, Khorrami A, Garjani A, et al. Acute treatment with metformin improves cardiac function following isoproterenol induced myocardial infarction in rats. Pharmacol Rep 2012; 64(6): 1476-1484.
  25. McFarlane RM, DeYoung G, Henry RA. The design of a pedicle flap in the rat to study necrosis and its prevention. Plast Reconstr Surg 1965; 35: 177-182.
  26. Karimipour M, Hassanzadeh M, Zirak Javanmard M, et al. Oral administration of alanyl-glutamine and glutamine improve random pattern dorsal skin flap survival in rats. Iran J Basic Med Sci 2018; 21(8):
  27. Lin B, Lin Y, Lin D, et al. Effects of bezafibrate on the survival of random skin flaps in rats. J Reconstr Microsurg 2016; 32(5): 395-401.
  28. Pinfildi CE, Liebano RE, Hochman BS, et al. Effect of low-level laser therapy on mast cells in viability of the transverse rectus abdominis musculocutaneous flap. Photomed Laser Surg 2009; 27(2): 337-343.
  29. Bagdas D, Cam Etoz B, Inan Ozturkoglu S, et al. Effects of systemic chlorogenic acid on random-pattern dorsal skin flap survival in diabetic rats. Biol Pharm Bull 2014; 37(3): 361-370.
  30. Karimipour M, Shojaei Zarghani S, Mohajer Milani M, et al. Pre-treatment with metformin in comparison with post-treatment reduces cerebral ischemia reperfusion induced injuries in rats. Bull Emerg Trauma 2018; 6(2): 115-121.
  31. Zhou G, Myers R, Li Y, et al. Role of AMP-activated protein kinase in mechanism of metformin action. J Clin Invest 2001; 108(8): 1167-1174.
  32. Ouchi N, Shibata R, Walsh K. AMP-activated protein kinase signaling stimulates VEGF expression and angiogenesis in skeletal muscle. Circ Res 2005; 96(8): 838-846.
  33. Zhang F, Fischer K, Komorowska-Timek E, et al. Improvement of skin paddle survival by application of vascular endothelial growth factor in a rat TRAM flap model. Ann Plast Surg 2001; 46(3): 314-319.
  34. Brown LF, Yeo KT, Berse B, et al. Expression of vascular permeability factor (vascular endothelial growth factor) by epidermal keratinocytes during wound healing. J Exp Med 1992; 176(5): 1375-1379.
  35. Shiota N, Nishikori Y, Kakizoe E, et al. Pathophysiological role of skin mast cells in wound healing after scald injury: study with mast cell-deficient W/W(V) mice. Int Arch Allergy Immunol 2010; 151(1): 80-88.
  36. Michlits W, Mittermayr R, Schäfer R, et al. Fibrin‐embedded administration of VEGF plasmid enhances skin flap survival. Wound Repair Regen 2007; 15(3): 360-367.
  37. Johnson KE, Wilgus TA. Vascular endothelial growth factor and angiogenesis in the regulation of cutaneous wound repair. Adv Wound Care (New Rochelle) 2014; 3(10): 647-661.
  38. Rivilis I, Milkiewicz M, Boyd P, et al. Differential involvement of MMP-2 and VEGF during muscle stretch-versus shear stress-induced angiogenesis. Am J Physiol Heart Circ Physiol 2002; 283(4): H1430-H1438.
  39. Heissig B, Rafii S, Akiyama H, et al. Low-dose irradiation promotes tissue revascularization through VEGF release from mast cells and MMP-9-mediated progenitor cell mobilization. J Exp Med 2005; 202(6):739-750.
  40. Chehelcheraghi F, Abbaszadeh A, Tavafi M. Skin mast cell promotion in random Skin flaps in rats using bone marrow mesenchymal stem cells and amniotic membrane. Iran Biomed J 2018; 22(5): 322-330.
  41. Ochoa-Gonzalez F, Cervantes-Villagrana AR, Fernandez-Ruiz JC, et al. Correction: Metformin induces cell cycle arrest, reduced proliferation, wound healing impairment in vivo and is associated to clinical outcomes in diabetic foot ulcer patients. PLoS One 2016; 11(7): e0159468. doi:10.1371/journal.pone. 0159468.
  42. Li DW, Liu ZQ, Wei J, et al. Contribution of endothelial progenitor cells to neovascularization (Review). Int J Mol Med 2012; 30(5): 1000-1006.
  43. Mao L, Huang M, Chen SC, et al. Endogenous endothelial progenitor cells participate in neovascularization via CXCR4/SDF-1 axis and improve outcome after stroke. CNS Neurosci Ther 2014; 20(5): 460-468.
  44. Ozturk A, Fırat C, Parlakpınar H, et al. Beneficial effects of aminoguanidine on skin flap survival in diabetic rats. Exp Diabetes Res 2012; 2012: 721256. doi:10.1155/2012/721256.
  45. Gribbe O, Gustafsson LE, Wiklund NP. Transdermally administered nitric oxide by application of acidified nitrite increases blood flow in rat epigastric island skin flaps. Eur J Pharmacol 2008; 578(1):51-56.
  46. Afraz S, Kamran A, Moazzami K, et al. Protective effect of pharmacologic preconditioning with pioglitazone on random-pattern skin flap in rat is mediated by nitric oxide system. J Surg Res 2012; 176(2): 696-700.
  47. Gribbe O, Samuelson UE, Wiklund NP. Effects of nitric oxide synthase inhibition on blood flow and survival in experimental skin flaps. J Plast Reconstr Aesthet Surg 2007; 60(3): 287-293.