Background: Ischemic wounds are intractable and require revascularization for healing. However, many patients with ischemic wounds have serious comorbidity, and revascularization surgery is not necessarily applicable for those patients, resulting in amputation of the lower limbs. Therefore, it would be useful to establish wound dressing materials with revascularization effects. Human amniotic membrane (hAM) has a variety of characteristics that make it potentially useful as a wound dressing material. However, there have been few reports on the angiogenesis promoting effects of hAM in ischemia-impaired wound. The aim of this study was to examine the efficacy of hAM as a wound dressing material for ischemic wounds.

Methods: Amniotic membranes were collected from delivered placentas with the consent of a pregnant woman who underwent a cesarean section. Fresh hAM were used within 6 hours of collection. Ischemic wounds were made at abdominal wall of male rats (SD, 9 weeks old, 300-350 g) by ligating the arteriovenous and nerve bundles of inferior abdominal wall and excising the abdomen skin with a diameter of 2.0 cm. Microvessel density (MVD) as an index of angiogenesis was measured by double staining with anti-α-SMA and anti-CD34 antibodies. The density of the number of blood vessels as well as the wound area were compared between hAM group and control group.

Results: The wound area after 5 days was significantly smaller in hAM group than in control group (335 vs. 459 mm2, p = 0.0051). The mean value of MVD was significantly higher in hAM group than in control group (19.0 vs. 15.1, p = 0.0026). Histological evaluation showed no obvious rejection of the hAM in this study.

Conclusion: This study showed the wound healing effect and the angiogenesis promoting effect of fresh hAM, indicating the usefulness of fresh hAM for treating non-invasively ischemic wounds.