Effects Of Different Intensity Of Magnetic Field On Peripheral Nerve Scar Formation In Rats

Objective The experiment simulates SD rats’ sciatic nerve injuries, exerts different field intensities of the same magnetic field to intervene the SD rats. At the end of the experimental period, the observer surveys the index of the sciatic nerve function and the change of nerve injury in nerve scarring, and discusses the way of field interventions promoting nerve repair mechanisms and magnetic interference effects on neural scarring.Methods The study selects 80 developed clean female SD rats as the subject, which were purchased and reared by Department of Animal Experiment Center of Hebei University. All the 80 rats are applied abdominal cavity anesthesia, along with skin-backup, disinfection,incision on the right side of the glutes and with the right side of the sciatic nerve free and exposed. Choose a sciatic nerve at the ischial tuberosity distal and proximal sciatic nerve branch. Use micro vascular clamp this sciatic nerve, fit card 30 seconds, cause the sciatic nerve damage of entrapment. Mark the entrapment with nylon suture, clean and suture the wound layerly, prepare for experimental observation. The 80 rats are randomly divided into control group and 0.2 m T group, 0.6 m T and 1.5 m T group, each group with 20 rats. Operate no intervention to control group, but respectively give strength 0.2 m T, 0.6 m T and 1.5 m T, 2hz frequency magnetic field interference to the postoperative experimental group 60 minutes a day. 21 days later, survey sciatic nerve function index(SFI), I collagen type immunohistochemical staining and transmission electron microscope, image analysis, etc.Apply single factor analysis of variance, then operate LSD- t-test in Pairwise comparison. P< 0.05 is considered statistically significance.Results The investigator obtains the following results by collecting observational index of each group of rats after 21 days’ treatment. Sciatic nerve function index(SFI) measurement results: experimental group curative effect is better than the control group; 0.6 m T group is better than the 0.2 m T and 0.2 m T group is better than the 1.5 m T. Differences between groups are all statistically significant(P < 0.01). The results of I-type collagen immunohistochemical staining observed under light: after dyeing, I-type collagen fibers are stained yellowish-brown at the markd sciatic nerve under the microscope. Compared with the experimental group, the control group have more evident yellowish-brown collagenhyperplasia in entrapment markd place, and even a small mass of collagen clumps is forming there, with nerve fiber sparse and a large number of vacuoles degeneration between organizations. Whereas compared with control group, the experimental groups have less collagen fibers, widely distributed nerve fibers, neat permutation and fresh free bubble degeneration. And the above performances are significant in 0.6m T group, with 0.2m T group followed closely. But 1.5m T group and the control group perform closely. Observed under transmission electron microscope, markd sciatic nerve can be seen as the following results:compared with experimental group, the control group has more disordered arrangement of myelinated nerve fiber,less clear boundary line and significant collagen fiber hyperplasia.The surrounding myelin mostly swelling and deforming and a small number of newborn myelin becomes regenerated and degenerated, demyelination has even performed. Whereas compared with control group, the experimental groups have clearer myelinated nerve fiber boundaries, neat rows, good visible myelin layer plate structure, less interstitial collagen fiber content, few myelin deformation and demyelinating performance. And 0.6 m T group is better than the 0.2 m T and 0.2 m T group is better than the 1.5 m T. Image analysis results: Ⅰ type collagen fiber hyperplasia of control group is more then experimental groups, hyperplasia of1.5 m T group is more than 0.2 m T group and more better than 0.6 m T. Differences between groups were statistically significant(P < 0.01).Conclusions By observing peripheral nerve scar formation of the rats, and through the presence of magnetic field intervention, intervention of different intensity magnetic field, the experiment finds that the magnetic field interference can suppress the scar formation in different degrees and can help repairing nerve lesions to be more normal form. Through the comparison of sciatic nerve function index, it also can be found that the magnetic field intervention can obviously promote the recovery of neural function, which is inseparable with its suppression of nerve scar formation. Meanwhile, under the same magnetic field, the same frequency and duration and within a certain scope, the greater the magnetic field strength is,the more obvious the influence of scarring is. But beyond a certain range of intensity, for example, if the magnetic field strength is too large, the effect may be greatly weakened. This may indicate that impact scar magnetic field strength within a certain range, the best in this range remains to be further research.