Effect of low-level laser therapy on healing of tenotomized Achilles tendon in streptozotocin-induced diabetic rats.

Diabetes mellitus (DM) is associated with musculoskeletal damage. Investigations have indicated that healing of the surgically tenotomized Achilles tendon was considerably augmented following low-level laser therapy (LLLT) in non-diabetic, healthy animals. The aim of the present study was to evaluate the effect of LLLT on the Achilles tendon healing in streptozotocin-induced diabetic (STZ-D) rats via a biomechanical evaluating method. Thirty-three rats were divided into non-diabetic (n = 18) and diabetic (n = 15) groups. DM was induced in the rats by injections of STZ. The right Achilles tendons of all rats were tenotomized 1 month after STZ injections. The two experimental groups (n = 6 for each group) of non-diabetic rats were irradiated with a helium-neon (He-Ne) laser at 2.9 and 11.5 J/cm(2) for ten consecutive days. The two experimental groups of diabetic rats (n = 5 for each group) were irradiated with a He-Ne laser at 2.9 and 4.3 J/cm(2) for ten consecutive days. The tendons were submitted to a tensiometric test. Significant improvements in the maximum stress (MS) values (Newton per square millimeter) were found following LLLT at 2.9 J/cm(2) in both the non-diabetic (p = 0.031) and diabetic (p = 0.019) experimental groups when compared with their control groups. LLLT at 2.9 J/cm(2) to the tenotomized Achilles tendons in the non-diabetic and diabetic rats significantly increased the strength and MS of repairing Achilles tendons in our study.

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.

Effect of low-level laser therapy on experimental wounds of hard palate mucosa in mice.

Under general anesthesia and sterile conditions, incision wound was induced in the hard palate mucosa of adult male mice. The wounds of groups 1 and 2 were irradiated daily with He-Ne laser at 3 and 7.5 J/cm2 for 120 and 300 s, respectively, while the incision wound of group 3 not exposed served as controls. On day 3 of injury, the laser-treated wounds contained significantly lower neutrophils than the wounds in the control group. By day 7 after injury, the laser-treated wounds contained significantly more fibroblasts and at the same time contained significantly fewer macrophages. In conclusion, an acceleration of the wound healing process of experimental wounds in the hard palate mucosa of mice at low-level laser therapy with a He-Ne laser at energy densities of 3 and 7.5 J/cm2 was observed.