The Experimental Study Of Pulsed Electromagnetic Fields On Sciatic Nerve Injury Repairing

Background:Peripheral nerve injury is a common disease which is a major reason for disability in clinical. The clinical performance and prognosis are different because of different reasons. Treatment methods include medication,physical therapy,surgical therapy and cell therapy. However, the functional recovery is not ideal. It is also an outstanding issue for nerve injury repairing in the clinical. How to promote the regeneration and functional recovery after nerve injury becomes a focus.Physical therapy is safe,non-invasion,convenient and effective ,which is favored by the clinical. A large number of studies suggest that pulsed electromagnetic fields can increase bone mineral density, and promote the fracture healing. It is often used in treating the osteoporosis. What's more, some reports said that pulsed electromagnetic fields can promote the peripheral nerve injury repairing, however, some do not support. Therefore, it is necessary to do the related experimental researches to make its effectiveness and the parameters clearly, also the mechanism. Providing the evidences in treating the peripheral nerve injury to realize the clinical values.Methods and materials:Experiment 1 According to the principle of randomized, 30 SD rats were divided into five groups: the normal control (group A), model control (group B), 0.3mT 2Hz (group C), 0.3mT 10Hz (group D), 0.3mT 40Hz (group E), each 6. Except the normal control group, the other rats were clamped into sciatic nerve injury model according to the literature. After finishing the model, we gave them location. C,D,E group accepted the treatment , the PEMF's field strength was 0.3mT, the frequency was 2Hz, 10Hz, 40Hz respectively. 2h/time, 2times/day, 30days altogether according the literature. the normal control group and model control group gave no intervention. Determined the sciatic nerve function index (SFI) and nerve conduction velocity(NCV) to all rats.Experiment 2 Select 30 SD rats, divided into 3 groups: model control(group A),normal control (group B)and treatment (group C), each 10. Except the normal control group, the other rats were received clamped sciatic nerve model according to the experiment 1. The treatment group were received 0.3mT 2Hz PEMF (according to the experiment 1's result),2h/time, 2times/day, model control group and normal control group were not given any treatment. Except the normal control group,we took 5 rats from the other two groups respectively,Then the nerves which was 5mm away from the clamped were sampled at the 1^st, 2^nd, 4^th week respectively, observed by electron microscope and immunohistoc-hemistry. Image pattern analysis of axon was done at the 4th week after operation to model control group and treatment group.Results:In the same strength and time, 2Hz group's SFI and NCV were higher than other frequency groups significantly (P<0.05). 2Hz PEMF make the course of Wallerian degeneration accelerated,schwann's cell proliferation increased significantly,regeneration of axon improved obviously. The NGFof the treatment group expressed more than the model control group (P<0.05).Conclusion:0.3mT 2Hz PEMF may be suitable for treating the sciatic nerve injury. one of the mechanism may be: PEMF accelerated the course of Wallerian degeneration,Schwann's cell proliferation,regeneration of axon, and the expression of NGF in nerve's fiber.