| Spinal nerve-related neuropathic pain is a one of the most big problems in clinical, and the current treatments to it are mainly concentrated on drugs, surgery and physical therapy, but the effect is often not satisfactory. The latest treatment in the foreign is implantable electrical stimulator, but its biggest drawback is that it need to be buried into the body through surgery and the cost of it is aslo very expensive, and those made it difficult to be used widely. The nature of neuropathic pain is the proliferation of a large number of ion channel proteins in axons and dorsal root ganglia of the ectopic excited foci. These proteins are opening and closing constantly and forming action potential and transmitting it to the hub. While electrical activities are always associated with the release of magnetic signals, so we can assume that:1. Ectopic nerve impulse generate its own electromagnetic signals, while the nerve cut magnetic field lines an induced electromotive force will be generated, when the induced electromotive force is in the opposite direction of the transmission of the nerve impulse it will block the nerve conduction, and that can made it an analgesic or even anesthetic effect.2. Through inhibiting the activity or translation of specific protein, both of injury and magnetic force can achieve that effect.In the early studies, we had the rotating magnetic field with a 60m/s line speed (6100r/min) acted on the lumbar of rats under anesthesia, and we fond that the withdraw reflex in rats was blocked, when we stopped the treatment the reflex recovered, and the withdraw reflex was blocked again when we repeated the experiment. Then the following experiments are based on the previous studies, and to avoid the influence of anesthetic we carried out the experiments with the rats awake. With the magnetic field lines cut the rats'thoracic spinal vertically we separate the whole experiment to fur steps to study the influence of noise, processing time, angular velocity and different directions of rotating machine on the tail flick latency (TFL) and mechanical withdrawal threshold (MWT) in rats.Part one Influence of processing time on the TFL and MWT in ratsObjective To observe the effects of rotating magnetic filed on the tail-flick latency (TFL) and mechanical withdrawal threshold (MWT) of rats and analyze it from processing time.Methods Eighty female SD rats were randomly assigned to 8 groups (n=10), which would be determined by 8 different time points (before treatment, treating for 10,20,30, and 60min,10,20,30min after treatment). The magnetic plate rotated near the lumbar of the rat at an angular of 7300r/min and the TFL and MWT were determined at each time point. The data were statistically analyzed.TFL test methods:Rats were fixed in a special fixed tank, with the back, head, limbs and tail of the rat exposed and the tail fall naturally, and the experiment would be started 15 minutes later. The TFL of the groups were recorded and determined using a light and heat pain measurement instrument stimulating the upper third of the tail with a constant temperature of 40℃, and all of the experimental parameters were unchanged.MWT Test Methods:During testing, rats were placed on a plexiglass platform which was placed on a wire mesh. The plexiglass platform is 30X30cm and is made of 3mm thick plexiglass. It contains 1.5mm diameter holes in a 5mm grid of perpendicular rows throughout the entire area of the platform. Make sure that the rats were stationary and standing on all four paws without additional pressure. The experiment would be started 15 min later. Placed the magnetic plate above the rats and make sure the fringe of plate close to the lumbar of the rats. The series of Von Frey hairs was applied from below the plexiglass platform to the central region of plantar surface of the left hind paw in ascending order beginning with the lowest hair (1.66g), and the test maintained for approximately 4s. A withdrawal response was considered valid only if the hind paw was completely removed from the platform or the appearance of vocalization from the rats. If withdrawal did not occur during the application of a particular hair, the nest larger hair in the series was applied in a similar manner. When the hind withdrawal occurred, an adjacent to the stimulus intensity level was given, until the appearance of a median 50% threshold by this up-down method and recorded the results. Repeated the test four times and a trial consisted of application of a Von Frey hair to the hind paw two times at 30s intervals.Results The effects of processing time on TFL and MWT of rats are different. Compared with that before treatment, TFL was statistically increased at treating for 10,20,30 and 60 min, and 10 and 20min after the treatment (P<0.05). TFL was statistically increased at treating for 10,20,30 and 60 min, and 10 after the treatment as compared with 30min after treatment (P<0.05). MWT increased significantly at treating for 30 and 60min, and 10 min after treatment as compared with that before treatment (P<0.05). And MWT was statistically increased at treating for 60 min as compared with treating for 10min and 30min after treatment, respectively (P<0.05).Conclusion Pain threshold can be increased by rotating magnetic field following the increase of the processing time, and the increa can last for a short time.Part two Influence of angular velocity on the TFL and MWT in ratsObjective To observe the effects of angular velocity on the TFL and MWT in rats.Methods Forty female SD rats were randomly assigned to 4 groups (n=10), and this part of experiment was carried out at an angular velocity of 6300,6800,7300 and 7800r/min respectively. According to the result of part one, all rats were treated for 30 min.TFL Test Methods:Rats were fixed in the special fixed tank, with the back, head, limbs and tail of the rat exposed and the tail fall naturally, and the experiment would be started 15 minutes later. Placed the fringe of magnetic plate close to the lumbar of the rats, and made the plate rotated clockwise. The TFL of the groups were recorded and determined using the light and heat pain measurement instrument stimulating the upper third of the tail with a constant temperature of 40℃30 min after each treatment.MWT Test Methods:Rats were fixed in the special fixed tank, and make sure that the rats were stationary and standing on all four paws without extra pressure. The experiment would be started 15 min later. Placed the fringe of magnetic plate close to the lumbar of the rats, and made the plate rotated clockwise.The Von Frey hairs are applied from below, through the platform to the plantar surface of the paw with up-down method to calculate the median 50% threshold 30 min after the treatment and recorded the results.Results Compared with the group of 6300r/min, TFL of other groups is significantly different (P<0.05). Compared with the group of 6800r/min, TFL of other groups is also significantly different (P<0.05). MWT of the 6300r/min group is significantly different compared with the 7300r/min and 7800r/min group, respectively (P<0.05).Conclusion Pain threshold can be increased by rotating magnetic field following the increase of angular velocity at a certain range.Part three Influence of noise on the TFL and MWT in ratsObjective To observe the Influence of noise of the rotating machine on the TFL and MWT in rats.Methods Thirty female SD rats were randomly assigned to 3 groups (n=10), which would be determined by 3 different treatments (treating with magnetic plate, aluminum plate and control group).TFL of magnetic plate group test method:Rats were fixed in the special fixed tank with the back, head, limbs and tail of the rat exposed and the tail fall naturally, and the experiment would be started 15 minutes later. Placed the fringe of magnetic plate close to the lumbar of the rats, and made the plate rotated clockwise at an angular velocity of 7300r/min. The TFL of this group were recorded and determined using the light and heat pain measurement instrument stimulating the upper third of the tail with a constant temperature of 40℃30 min after the treatment. Aluminum plate was not magnetic and TFL of this group were recorded and determined just as the magnetic plate group. TFL of control group were recorded 30 min after the rats were fixed without any treatment.MWT of magnetic plate group test method:Rats were fixed in the special fixed tank, and make sure that the rats were stationary and standing on all four paws, and the experiment would be started 15 min later. MWT of this group were determined and recorded with Von Frey hairs 30 min after the treatment. MWT of aluminum plate group were recorded and determined just as the magnetic plate group. MWT of control group were recorded 30 min after the rats were fixed without any treatment.Results Compared with other groups, TFL and MWT of magnetic plate group are statistically increased (P<0.05). Significant difference on TFL and MWT were not found between the control and aluminum plate group (P>0.05).Conclusion Pain threshold can be increased by rotating magnetic field at an angular velocity of 7300r/min and treating for 30min.Part four Influence of rotating machine in the opposite direction on the TFL and MWT in ratsObjective To observe the Influence of rotating machine in the opposite direction on the TFL and MWT in rats.Methods Twenty female SD rats were randomly assigned to 2 groups (n=10), which would be determined by 2 different treatments (treating with magnetic plate rotated clockwise, and rotated counterclockwise, respectively).TFL of clockwise group test method:Rats were fixed in the special fixed tank with the back, head, limbs and tail of the rat exposed and the tail fall naturally, and the experiment would be started 15 minutes later. Placed the fringe of magnetic plate close to the lumbar of the rats, and made the plate rotated clockwise at an angular velocity of 7300r/min. The TFL of this group were recorded and determined using the light and heat pain measurement instrument stimulating the upper third of the tail with a constant temperature of 40℃30 min after the treatment. TFL of counterclockwise group test method:This group were treated with magnetic plate rotated counterclockwise and TFL were recorded and determined just as the clockwise group.MWT of clockwise group test method:Rats were fixed in the special fixed tank, and make sure that the rats were stationary and standing on all four paws. The experiment would be started 15 min later. The MWT of this group were determined and recorded with Von Frey hairs 30 min after the treatment. MWT of counterclock-wise group were recorded and determined just as the magnetic plate group.Results Rats were treated with rotating magnetic plate in opposite directions and significant difference on TFL and MWT were not found between the groups(P> 0.05).Conclusion Pain threshold can be increased by magnetic field rotated both clockwise and counterclockwise. |
PDF Full Text Request