The Photosensitize Methylene Blue-Mediated Photodynamic Theray On The Efficacy Of Pain Threshold In Rats

Part1: EVALUATION OF ANALGESIC EFFECT OF PHOTOSENSITIZER METHYLENE BLUE USING ELECTRICITY PAIN THRESHOLD ASSAYObjective The aim of the present study is to precisely evaluate analgesic effect of methylene blue using electricity pain threshold assay. Method Fifty SD rats were used in this study, Four groups of rats were given methylene blue by local injection into the sciatic nerve at the concentration of 0.25%,0.5%,0.75% ,1% respectively. The rats in the fifth group received distilled water injection served as a normal control group. The pain threshold of rats was measured by a BL-410 biology function experiment system apparatus at 1h, 2h, 3h, 4h, 6h, 8h, 12h, 24h post treatment. Results The peak analgesic effect at the injection site occurred at 4h after administration of methylene blue. There was a very significant difference(P<0.01)between the pain threshold recorded in the 0.75% and 1% treated groups and the distilled water group. Conclusion Our findings demonstrated that Methylene blue can elevate pain threshold value. Methylene Blue can be caused by demyelination of nerve fibers and axonal injury like change, but over time to reduce the extension of axonal injury, and to nearby non-serious impact on the organization Part2:THE PHOTOSENSITIZE METHYLENE BLUE-MEDIATEDPHOTODYNAMIC THERAY ON THE EFFICACY OF PAIN THRESHOLD INRATSObjective: By observing the photosensitizer methylene blue-mediated photodynamic therapy (PDT) on the efficacy of pain threshold in rats to provide a new way of thinking and methods. Method: Fixed rats and located the right sciatic nerve in rats. The rats in five groups of rats received 0.75%. Methylene blue injection were given department of vertical illumination for 0 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes , 30 minutes respectively. The rats in the other five group received distilled water injection were given the same light respectively. The pain threshold of rats was measured by a BL-410 biology function experiment system apparatus at 0.5, 1h, 2h, 3h, 4h post treatment. Results :Whether the use of methylene blue on rat affect the pain threshold; Different illumination time of rats affect the pain threshold; Different illumination time and the drug interaction between the two factors that effect. Conclusion Photosensitizer methylene blue-mediated photodynamic therapy can increase the pain threshold of rats, the role of photodynamic therapy can cause degeneration of peripheral nerve fibers occurred.