Pentoxifylline improves cutaneous wound healing in streptozotocin-induced diabetic rats

Worldwide, 15% of the 200 million diabetics suffer from diabetic wounds. In 1997, the cost for amputation of toes and limbs that resulted from infected diabetic foot ulcers ranged from $25,000-$40,000 per incident. Increasing numbers of research have shown the positive influence of pentoxifylline (PTX) on healing skin wounds. In this study, we evaluate the effect of systemic PTX (25mg/kg bid) on wound healing in 80 diabetic rats (DB) by secondary intention. Wounds (20 mm × 5 mm) were identically inflicted on the skin area of the backs of all rats. On day 15 following surgery, a band of skin (4 mm × 60 mm) that contained wound was extracted for biomechanical testing. For histologic analysis, both experimental (DB+PTX) and control, receiving distilled water (DB+DW) groups were further subdivided into day 3 and 7 groups. Rats were sacrificed three and seven days after surgery, and a sample from each wound was taken. All specimens were sectioned stereologically and stained with H&E. Cell counts were performed by stereological methods. Semi-quantitative evaluation of matrix metalloproteinases (MMPs) and inhibitor-1 was performed by Reversed Transcription-PCR and UVI TEC software. For statistical analysis we used student's t-test. Collectively, the results of this study demonstrate that there was significant improvement with PTX in all biomechanical parameters. Histologically, PTX reduced inflammation by day seven. Quantitatively, by day five, PTX reduced expression of MMPs and increased TIMP-1 expression. These findings revealed that PTX significantly improved wound healing indices in streptozotocin-induced DB.