A reduced mortality due to hyperglycaemia was noted since the development of insulin treatment for type I diabetes and various oral hypoglycaemic agents for type II diabetes. Nevertheless the chronic metabolic disorder, Diabetes Mellitus, remains an important cause of morbidity and mortality due to a series of common secondary metabolic complications. Patients with diabetes have an increased tendency to develop infections of the skin. Healing of skin lesions in diabetics evolves often relatively slow and the lesions tend to be more severe than in non-diabetics. Endeavouring to accelerate the healing process of skin lesions in diabetic patients, this preliminary in vitro study investigates the efficacy of green Light Emitting Diode (LED) irradiation on fibroblast proliferation of cells in hyperglycaemic circumstances. In an attempt to imitate the diabetic environment, embryonic chicken fibroblasts were cultured in hyperglycaemic medium (30.000mg Glucose per litre Hanks Medium). LED irradiation was performed three consecutive days with a wavelength of 540 nm and a power output of 10 mW, at 0,6 cm distance from the fibroblasts. Each treatment lasted 3 minutes, resulting in a surface energy density of 0,2 J/cm2. Statistical analysis revealed that LED irradiation at the applied parameters induced a higher rate of proliferation in hyperglycaemic circumstances after irradiation than in the same circumstances without irradiation. Regarding these results the effectiveness of green LED irradiation on cells in hyperglycaemic circumstances is proven. To ensure the effectiveness and to evaluate the value of LED irradiation in vivo, further research is required.
Oncological research and cancer treatment are more common in human medicine than in veterinary medicine. Nevertheless the latest decennium chemotherapy, radiotherapy and surgery also figure largely in the cancer treatment of pets. For this matter, the present study tried to explore the applicability of Photodynamic Therapy (PDT) as a proper and advantageous alternative for those treatments. PDT using topical 5-aminolaevulinic acid (5-ALA) cream was applied on superficial squamous cell carcinomas (SCC) at the nasal planum of two cats. Five hours after the cream was applied, the photosensitizing agent was removed and the sensitized area was irradiated with a red Light Emitting Diode (LED) contrivance with a wavelength of 660 nm. LED irradiation was administrated during 20 minutes, at a power output of 80 mW, with an energy density outcome of 38 J/cm2. The day after ths irradiation, the tumor area became erythematous and somewhat oedematous. After two days a scab occurred. Long-term post treatment observation showed complete removal of the malign cells related with regain of normal skin structure after three weeks. Follow-up period of one year for the first case and of two months for the second case revealed no recurrence. These promising results indicate that PDT is a possible alternative method to treat superficial skin tumors. Especially when taking into account that chemotherapy and radiotherapy are time-consuming treatments and that surgery (complete removal of the nasal planum) is not an esthetical solution.
The effectiveness and applicability of a variety of light sources, in the treatment of wounds has thoroughly been investigated, in vitro as well as in vivo. The current commercial availability of Light Emitting Diode (LED) sources therefore also invites research to explore the effect of low power infrared, red and green light on wound healing, e.g. by means of fibroblast proliferation. Therefore a controlled and randomized study on cultured embryonic chicken fibroblasts was conducted. The fibroblasts were irradiated during three consecutive days, at several wavelengths (950 nm, 660 nm and 570 nm) and a respective power output of 160 mW, 80 mW or 10 mW. Treatment duration varied from 1 minute to 3 minutes to obtain a surface energy density of 0.9 J/cm2 (infrared and red light) or 0.2 J/cm2 (green light). Statistical analysis revealed that LED irradiation for all three wavelengths induced a higher rate of proliferation in comparison of the control group. This difference was statistically significant (p < .001). With regard to the amount of proliferation the green probe yielded a significantly higher number of cells, than the red (p < .001) an the infrared probe (p < .001). Furthermore, the red probe provided a higher increase (p < .001) than the IR probe. LED irradiation results in an increased fibroblast proliferation in vitro. This outcome postulates beneficial stimulatory effects of LED at the applied wavelength, energy density and power output on wound healing in vivo. Further investigation is necessary to examine this hypothesis.
Variable effects of different forms of light therapy on wound healing have been reported. This preliminary study covers the efficacy of infrared light emitting diodes (LED) in this domain.
Cultured embryonic chicken fibroblasts were treated in a controlled, radomised manner. LED irradiation was performed three consecutive days with a wavelength of 950 nm and a power output of 160 mW, at 0,6 cm distance from the fibroblasts. Each treatment lasted 6 minutes, resulting in a surface energy denstiy of 3,2 J/cm2.
The results indicated that LED treatment does not influence fibroblast proliferation at the applied energy density and irradiation frequency (p=0,474).
Meanwhile the effects of LED on wound healing in vivo were studied by treating a surgical incision (6 cm) on the lateral side of the right foot in a male patient. The treatment started after 13 days, when initial stitches were being removed. The same parameters as in the in vitro study were used but the treatment was performed five times. The healing could only be evaluated clinically, the irradiated area (2,6 cm) showed a more appropriate contraction, less discoloration and a less hypertrophic scar than the control area (3,4 cm).
The used parameters failed to demonstrate any biological effect of LED irradiation in vitro, although the case study on the other hand illustrated a beneficial effect.
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