Momordica charantia (MC) commonly known as bitter melon are a source of flavonoid and phenolic substances with potential utility to assist in wound healing. This study examined the effect topical application of an aqueous MC extract on healing in type II diabetic rodent model. The main end-points were epithelial closure rate, wound granulation tissue quality, growth factor concentration and inflammatory cell infiltration.

 Diabetes mellitus was induced in one day-old male Sprague Dawley rats by injection of STZ (85 mg/kg). Twelve weeks later a 3 cm² wound was placed in the back of each rat and the wounds were treated 2 per day with topical (MC) or vehicle alone (V). Some animals were treated with oral MC (20mg/kg). Similarly treated non diabetic animals acted as control. The animals were terminated at day 5, 10 and 15 and wound area, wound re-epithelialisation, granulation tissue myofibroblast and vessel number, inflammatory cell infiltrate, growth factors and collagen content was determined by immunohistochemistry (IHC). Hydroxyproline content was measured by colorimetry.

Animals treated with STZ had increased blood glucose level (C=5.25±0.20 vs D=9.15±0.94) and decreased serum insulin (C=1.79±0.28 vs D=0.78±0.07 ng/ml), body weights were not altered. Topical MC, improved wound closure in diabetic animals (P<0.05) to near normal levels and increased granulation tissue quality as evidenced by collagen content and vessel number on IHC. Hydroxyproline content, PMN and macrophage numbers were also normalized. Topical MC also significantly increased wound growth factors (including PDGF, VEGF, and TGF-β1). Oral treatment with MC was without effect on any of the parameters studied.

The results of this research showed that the topical application of an aqueous extract of MC fruit improved the wound healing and wound quality in diabetic rats. Whether this effect is via anti-inflammatory actions alone requires further investigation.