Effect of non-coherent infrared light (LED, λ945 ± 20 nm) on bone repair in diabetic rats-morphometric and spectral analyses.

Phototherapy using coherent light (lasers) and non-coherent light (light-emitting diodes (LEDs)) has been investigated for the purpose of biomodulation in biological tissues. Several effects can be expected, including pain moderation, biostimulation of cellular tropism, anti-inflammatory effects, regular circulatory stimulation, and tissue repair. The aim of this study was to evaluate the effect of LED (λ945 ± 20 nm, 48 mW) therapy on the regeneration process in femoral lesions of rats (Wistar). Seven irradiation sessions were held, with a 48-h interval between sessions. The animals were euthanised 14, 21, and 28 days after surgery. Bone samples were analysed by histomorphometry, micro X-ray fluorescence spectroscopy, scanning electron microscopy, and optical densitometry. The results demonstrated the effective positive influence of low-intensity LED therapy using the near-infrared region on the tissue repair process in diabetic animals, especially in the early stages of repair (14 and 21 days after surgery). It can be concluded that LED therapy positively influences bone formation in the early stages of the bone repair process in non-diabetic and diabetic animals, without causing changes in the optical density and volume of tissue in the final stages. No influence of LED therapy was observed on the percentage of calcium, percentage of phosphorus, Ca/P ratio, or optical mineral density in non-diabetic animals. However, increased mineral concentration was evident in the diabetic animals treated with the LED during the repair process.

In vitro evaluation of photodynamic therapy using curcumin on Leishmania major and Leishmania braziliensis.

Cutaneous leishmaniasis is an infectious disease caused by the Leishmania protozoan. The conventional treatment is long-lasting and aggressive, in addition to causing harmful effect. Photodynamic therapy has emerged as a promising alternative treatment, which allows local administration with fewer side effects. This study investigated the photodynamic activity of curcumin on Leishmania major and Leishmania braziliensis promastigote. Both species were submitted to incubation with curcumin in serial dilutions from 500 µg/ml up to 7.8 µg/ml. Control groups were kept in the dark while PDT groups received a fluency of 10 J/cm(2) at 450 nm. Mitochondrial activity was assessed by MTT assay 18 h after light treatment, and viability was measured by Trypan blue dye exclusion test. Morphological alterations were observed by Giemsa staining. Confocal microscopy showed the uptake of curcumin by both tested Leishmania species. Mitochondrial activity was inconclusive to determine viability; however, Trypan blue test was able to show that curcumin photodynamic treatment had a significant effect on viability of parasites. The morphology of promastigotes was highly affected by the photodynamic therapy. These results indicated that curcumin may be a promising alternative photosensitizer, because it presents no toxicity in the dark; however, further tests in co-culture with macrophages and other species of Leishmania should be conducted to determine better conditions before in vivo tests are performed.