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Effects of Rotating Magnetic Field on Pain Threshold in Rats’spinal Cord: an Analysis from Processing Time and Angular Velocity

Author: AnShuKang
Tutor: ZhouChuSong；ChenZhong
School: Southern Medical University,
Course: Orthopedics
Keywords: Rotating magnetic field Time Angular velocity Direction Pain threshold
CLC: R741
Type: Master's thesis
Year: 2011
Downloads: 9
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Abstract

Spinal nerve neuropathic pain is one of the thorniest problems in the clinical approach for drugs, surgery and physical therapy treatment, the effect is often not ideal. Abroad, the latest treatment method is the application of implantable electrical stimulation, and its biggest drawback is the need for surgery buried the body, and the cost is very expensive and difficult to promote. The nature of neuropathic pain ectopic excited stove axons and dorsal root ganglion ion protein channels, they are constantly opening and closing, the formation of action potential transmission to the hub, while the electrical activity will be accompanied by a magnetic signal the issuance dare assumptions: 1. nerve ectopic impulse generation change of the electromagnetic signal with its own characteristics, the when nerve cutting magnetic field lines, the direction of the induced emf nerve conduction in the opposite direction, you can block nerve conduction , analgesic or anesthetic effect. Injury and magnetic can affect the nerve membrane protein, inhibition of the specific activity of the protein or to affect the expression of the protein can be translated to achieve the purpose of analgesia. Rotating constant magnetic field in the early days of this study has been to 60m / s line speed (6100r/min) in the anesthetized rat lumbar flinching results in rats is blocked, stop the role flinching recovery , and the role of flinching and then disappear. The subject on the basis of the previous experiment, take the rats in the awake state, exclude the anesthesia flinching interference rats to study the magnetic field lines perpendicular cut rat thoracolumbar spine when the impact of noise on the pain threshold of rats, respectively treated rats the opposite direction of the magnetic field, clear changes in rat pain threshold processing rat spinal magnetic fields in different directions, and further study of the different duration of action of the rotating magnetic field, different speeds under changes in rat pain threshold, and then analyzes the magnetic field analgesic mechanism to provide a theoretical basis for further to explore magnetometer analgesic and magnetic anesthesia. To observe the effect of time on the first part of the spinal cord rotary magnetic field rat pain threshold the rotation constant magnetic fields of different time of the rat tail flick pain threshold (TFL) and mechanical paw pain threshold (MWT). 80 female SD rats were randomly divided into eight groups, according to the test point in time different treatment group (control group), 10,20,30,60 min after treatment group and treatment 60min stop after 10, 20, 30min group, n = 10. Rotating magnetic field at a constant speed (7300r/min) treated rats lumbar rat tail flick latency (TFL) and mechanical paw withdrawal threshold of pain (WMT) were measured at the corresponding time points, the results were statistically analyzed. The TFL test methods: the rats in the awake state is fixed in a specially made plastic fixed tank exposed rat dorsal mouse head, limbs, tail, rat tail fall naturally 15min after the beginning of the experiment. Experimental groups run out of hot measured pain instrument to stimulate the upper third of the rat tail (the experimental measured data are to stimulate the premises resulting in a constant temperature of 40 ℃, and all the stimulation parameters are the same), followed by test magnetic field rats corresponding time before the rats TFL, clockwise magnetic field processing TFL, and record the results. MWT test methods: a 3mm thick perspex plate (30cm × 30cm, with a diameter of 1.5mm orifice, the orifice pitch 5mm) placed in a metal sieve, the fixed groove fixation rats it volts on plexiglass. To be rats in a plexiglass box to adapt the experiment after 15 min, rotating magnetic field is placed the rat above and close to the rat spinal and corresponding experimental time points with Von Frey filaments the vertical stimulation of rat left hindlimb plantar Central duration lt; 4S, the rat lift foot or bray behavior appears as a positive reaction, otherwise negative. Determination of First 1.66g when the intensity of the stimulus can not cause a positive reaction, given the adjacent large an intensity of stimulation, such as the positive reaction given to efforts to stimulate the adjacent small one, so continuously, until the emergence of the first positive and negative reaction to ride cross, and then continuously measured 4 times and record MWT interval between the two tests 30S. Von Frey filaments projected 50% paw withdrawal threshold in this up-down method. Different duration of action of the rotating magnetic field rats TFL different (F = 35.563, P = 0.000). 10min group compared with the control group, stopped after 30min group with whom the difference is not significant, and the rest of the group and the control group, the differences were significant (P lt; 0.05); stopped after 30min treatment 20,30,60 min group and stop TFL between the mean difference was statistically significant (P lt; 0.05). Different duration of action of the rotating magnetic field rats MWT different (F = 7.037, P = 0.000). And stopped after 10min 30,60 min after treatment compared with the control group had significantly improved, the differences were statistically significant (P lt; 0.05); 60min group treated with 30min group after the 10min group and stop difference was statistically significant ( P lt; 0.05). The conclusions of the rotating magnetic field can enhance the pain threshold of rats treated rats some time, stop threshold rise after deal with short-term after-effects. To observe the effect of the second part of the spinal cord rotary magnetic field angular velocity of the pain threshold in rats different role of angular velocity of the rotating magnetic field of foot pain rat tail flick pain threshold (TFL) and mechanical withdrawal threshold (MWT). 40 female rats were randomly divided into four groups of 10 each. According to the experimental one experiment II magnetic field processing time was 30min. The TFL test methods: the rats in the awake state is fixed in a specially made plastic fixed tank exposed rat dorsal mouse head, limbs, tail, rat tail fall naturally 15min after the beginning of the experiment. Rat thoracolumbar spine close to the edge of the disk, the start in a clockwise direction the magnetic field, the magnetic field reaches a predetermined speed, and start timing. The light heat measured pain instrument at a constant temperature of 40 ℃ 30min after stimulation of the rat tail on the third of the record TFL, followed by the completion of the group of 10 rats the TFL test and record the results. The MWT test method: fixed slot fixed rats, rats volts on the plexiglass without giving additional pressure, rotating magnetic field placed the rat above and close to the rat spinal. Pending rat in a plexiglass box adapt to the experimental operation, start in a clockwise direction the magnetic field, the magnetic field reaches a predetermined speed and start timing after 15min. With the vertical Von Frey filaments stimulation of rat left hindlimb plantar Central time 30min duration ≤ 4S projected 50% paw withdrawal threshold up-down method, followed by the completion of the group of 10 rats MWT tests and record the results. Results different speed constant speed magnetic field rats TFL (F = 13.591, P = 0.000). The results showed that each group compared with 6300r/min rats TFL mean there were significant differences (P lt; 0.05); each group compared with 6800r/min rats TFL mean were significant differences (P lt; 0.05 ). Constant speed of different speed of the magnetic field rats MWT different (F = 3.668, P = 0.021). 6300r/min respectively, compared with 7300r/min and 7800r/min between the two groups of MWT were significantly different (P lt; 0.05). Conclusion pain threshold is increased with the rise of the magnetic field rotational speed within a certain range. The third part of the mechanical rotation noise on the pain threshold of rats purposeful mechanical rotation of the impact of noise on the pain threshold of rats in the experiment. Methods 30 female SD rats were randomly divided into three groups, namely, the disk group, the the aluminum disk group and blank control group. The TFL test of the disk group: the test rats were fixed exposed rat dorsal rat head, limbs, tail, tail fall naturally after experimental 15mmin. Rat thoracolumbar spine close to the edge of the disk, the start in a clockwise direction the magnetic field, the magnetic field reaches 7300r/min, and start timing. The light heat measured pain instrument 30min after stimulation of the rat tail in the upper third of a constant temperature of 40 ℃, followed by the completion of the group of 10 rats the TFL test and record the results. TFL test of the aluminum disk group: aluminum disk group non-magnetic rotating aluminum disk with the same parameters treated rats thoracolumbar spinal cord, test practices the same disk group. Blank control group not treated in the experimental environment, 30min after test rats TFL. The fixed disk group rat the MWT test: disk rats, rats fell after 15min plexiglass panel to start the experiment. Magnetic field treated rats 30mmin with Von Frey filament the vertical stimulation of rat left hind leg plantar central test rats MWT and record the results. The aluminum plate rats MWT test: a non-magnetic aluminum plate treated rats, the same parameters and the same method of test rats the MWT and record the results. The blank control rats the MWT test: the rats fixed, placed in a laboratory environment without other treatment, 30min after test rats MWT and record the results. Magnetic field group compared with the other two groups. Rats TFL have significantly improved and the difference was statistically significant (F = 61.582, P = 0.000); compared to the other two groups, field rats also significantly improved MWT, statistical difference significance (F = 9.586, P = 0.002). Conclusion 7300r/min rotation constant magnetic field treated rats lumbar spine after 30 minutes, the pain threshold in rats significantly increased, the rat TFL and the MWT significantly longer than those in the other two groups. Different role in the direction of the fourth part of the magnetic field of the rat pain threshold the purposeful magnetic field treatment of the rat spinal rats TFL and MWT in a clockwise and counterclockwise, respectively. 20 female SD rats were randomly divided into two groups, divided into the magnetic field the clockwise group and magnetic field counterclockwise group. The clockwise group TFL test: the test rats were fixed exposed rat dorsal rat head, limbs, tail, tail fall naturally 15min after the beginning of the experiment. Rat thoracolumbar spine close to the edge of the disk, the start in a clockwise direction the magnetic field, the magnetic field reaches 7300r/min, and start timing. The light heat measured pain instrument 30min after stimulation of the rat tail in the upper third of a constant temperature of 40 ℃, followed by the completion of the group of 10 rats the TFL test and record the results. The counterclockwise group TFL test: the counterclockwise group to counterclockwise start magnetic field test rats TFL same way clockwise group and record the results. Clockwise group rat the MWT test: Disk group rats were fixed, the rat volts after 15min plexiglass panel to start the experiment. Magnetic field clockwise treated rats 30min with the vertical Von Frey filaments stimulation of rat left hindlimb plantar Central test rats MWT and record the results. Counterclockwise rats MWT test: before the experiment to prepare with the former, counterclockwise counterclockwise start magnetic field group, 30min after test rats MWT and record the results. Results of the magnetic field in different directions treated rats lumbar group rats TFL showed no significant differences, the difference was not statistically significant (t = -0.288, P = 0.777); the group between rats MWT comparison no significant difference The difference was not statistically significant (t = -0.830, P = 0.417). Conclusion handling rat spinal magnetic fields in different directions, both make the pain threshold in rats enhance, and no significant differences between the different directions. Clockwise or counterclockwise treated rats in the lumbar spine, can have the same effect.

Effects of Rotating Magnetic Field on Pain Threshold in Rats’spinal Cord: an Analysis from Processing Time and Angular Velocity

Abstract

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