RESUMO
Introduction: Staphylococcus aureus is one of the critical pathological bacteria. This bacterium had developed a variety of genetic mutations that made it resistant to drugs and more harmful to humans. In addition, all attempts to design a specific vaccine against S. aureus have failed. Therefore, this experiment was designed as a trial for vaccine production, by using a photodynamic treatment (PDT) through partial biological inhibition. The PDT of bacteria mainly focused on reducing the activity of staphylocoagulase (SC), which has a protective feature for bacteria. This study aimed to examine the photodynamic effect of combining a specific wavelength of a laser and a certain dilution photosensitizer, methylene blue (MB) dye. The possible PDT effect on the inhibition of pathogenic enzymatic activity was predicted. This study also aimed to evaluate the inhibitory effect of PDT on the total bacterial account (viability) simultaneously with SC assay. Methods: A 650nm wavelength diode laser was used with 100 mW output power and 2 minutes of exposure time. Dye dilutions were 50, 100, 150 and 200 µg/mL. The viability of bacteria after and before laser treatment was calculated using single plate-serial dilution spotting methods. The activity of SC was detected by using human plasma for 4 hours incubation of crude-substrate interaction. Results: The results revealed a significant decrease in enzyme activity and colony-forming units (CFU) after irradiating bacterial suspension with 150 g/mL MB, as well as a decline in CFU. However, irradiation with a laser alone showed a significant increase in SC activity and CFU for the same exposure time. Conclusion: Besides reducing the production of SC activity, PDT significantly inhibited the viability of S. aureus. The application of MB photosensitizer at a concentration of 150 g/mL in combination with a laser wavelength of 650 nm resulted in a complete decrease in the SC activity value as well as the viability of bacteria.
RESUMO
There were many studies that attempt to measure the effect of growth factors of platelets through platelet-rich plasma (PRP) techniques on repairing of different human tissues and their efficiency either by platelets account or measuring the concentrations of growth factors secreted from platelets at various experimental conditions, to get the optimal parameters for platelets functions in healing processes. There were little trails dealing with laser and PRP for accelerating healing process that generally takes two methods, either by studding the stimulation effect of LLLT (low-level laser therapy), by subjecting laser irradiation on injured part and left for a period of time that is necessary for photobiostimulation of cell proliferations, then PRP treatment followed, or by studding the direct effects of laser on PRP factors activity. The objectives of this study are to investigate the indirect and prolonged influence of laser irradiation (650 nm with 100 mW output power) on healing processes of knee joints with induced osteoarthritis (OA), by comparison of radiated and non-radiated PRP on repairing of joint cartilage. In material and methods, we used 9 rats divided in to four groups: C1, control without any treatment, for positive comparisons of healing; C2 and C3, controls with induced OA, left for 14 days, then sacrificed for histological analysis of negative comparisons; and P and L groups that had induced with OA for 14 days and then treated with non-irradiated and radiated PRP, respectively. Preparation of PRP (condensed platelets account with high concentration of growth factors) in order to accelerate repairing processes on induced- osteoarthritis cartilage in rats groups. To estimate the efficacy of photobiostimulation or photobioinhibition on platelets' granules, we determine the absorbance of PRP by spectrophotometer. The technique was based on PRP, as a feature of platelets quantity, that compares the quality of PRP on healing of induced osteoarthritis with and without irradiation of laser, using Wistar rats as a model. The quality of platelets was measured by time required for healing according to histopathological observations and grades of OA. Finally, the results were analyzed statistically using ANOVA test (P = 0.05). Our conclusion was emphasizing the idea of inhibiting the effect of LLLT on growth factors of PRP that is responsible of speed up healing of OA.
