| Objective: The brachial plexus merged blood vessel damage is a severe combined trauma, caused mainly by severe car accidents, machines extrusion, gun shots and sharp instruments. Because of its complex condition and the special anatomic position of the wound, at present treatment on this kind of patients focuses in treating the damaged brachial plexus, but neglecting the repair of damages to the blood vessel. Although the body still might survive, but whether the low blood current capacity would have the adverse effect to the nerve regeneration and the function restoration of the muscle that lost nerves are still unknown. This research intends to establish the big mouse experimental model, observe the impact of blood shortage on neuranagenesis after the brachial plexus repair, and discuss its function and the mechanism, thus provide the theoretical basis for the more reasonable and effective clinic treatment to the repair of brachial plexus damage.Methods: Select 36 healthy SD big mouse, body weight 400 ~ 450g, male or female, divide them into the experimental group and comparison group by random choice of body weight serial number, each group of 18. After being anaesthetized by abdomen injection of chloral hydrate, apply a declined cut under the right-side collarbone, snip the pectoralis major and pectoralis minor, exposes and separates the brachial plexus bundles and the axillary artery, then under the 10-time surgical microscope, snip it at the starting part of the outside bundle, then use 11-0 non- wound nylon line to suture the nerve ends. For the experimental group at the same time, the axillary artery is cut off at its staring part and then ligated. While nothing is done to the artery of the comparison group. Myo-elctrograph studies are carried out 4 weeks, 8 weeks, 12 weeks respectively after the operation to record the incubation period and the wave amplitude of the musculocutaneous nerve, then the samples of the muscle and the nerve are taken to conduct the light microscope and electric microscope observation, for muscle amyotrophy and nerve regeneration, then a statistics analysis is carried out on each group of data.Results:1 Myo-electrograph: due to the limited length of the samples taken in this experiment, the stimulating electrode is too close to the acceptive electrode, which will be easily influenced by the volume conduction, therefore, the incubation period data is taken to avoid the surface distance error, and the swing measurement can reflect the number of axons conducting the excitation. The result of the experiment shows there is a substantial difference between the experimental group and the control group, the incubation period and wave length of the experimental group is distinctively lower than those of the control group.2 Neuro-histological Examination: the light mirror observation on the experimental group of 4 weeks after operation shows a distinct lower number of myelinatel nerve fiber than that of the control group, and smaller in diameter, thinner in the thickness of myelin sheath, more irregular in form, more loosely disposed, and more connective tissue between bundles; whilst the control group shows slightly moremyelinatel nerve fiber, and the proportion of the bulky fibers is big, thicker myelin sheath, less myelin sheath resolution, less connective tissue between bundles. For the experimental group of 8 weeks after the operation, there are substantial increase of myelinated nerve fiber, but no substantial increase in the proportion of the bulky fibers, the myelin sheath is relatively thicker, the connective tissue between bundles are less; whilst for the control group, the bulky fibers are distinctly more, the thickness of myelin sheath is even, its outlook is complete, the distribution of the nerve fibers are even, form is regular, the no connective tissue hyperplasia is seen between bundles. And for the data after 12 weeks of the operation, the experimental group shows that number of moremyelinatel nerve fibers are substantially increased, the proportion of the bulky fibers is bigger, the myelin sheath gets thicker, few resolution of myelin sheath are seen, and the connective tissue between bundles are decreased. Whilst for the control group, the bulky fibers are distinctively more, the myelin sheath is thick, the outlook of axon is complete and clear, no connective tissue is seen between bundles, the nerve fiber has grown mature. Five visions are taken randomly on each sample under the 400-time light microscope, the number of myelinated nerve and the thickness of myelin sheath are measured, and their average value is taken and compared. The result shows that the number of myelinated nerve and the thickness of myelin sheath of the experimental group is distinctly lower than that of the control group.Under the electric microscope on the experimental group of 4 weeks after the operation, the residue of myelin sheath degeneration and axon fragment is still seen, there is only little amount of newly born fibers, the structure of myelin sheath is loose and irregular, the cell organ inside the axon is few; whilst for the control group, the newly born nerve fibers are relatively more than that of the experimental group, the structure of myelin sheath is loose and irregular, the cell organ inside the axon is few. For 8 weeks after the operation, the experimental group shows increase in the number of newly born nerve fibers, oedema on the myelin sheath is obvious, the structure is a bit more regular than before, and vacuole is seen between axon and myelin sheath. Whilst the control group shows an increase in the number of newly born nerve fibers, oedema on the myelin sheath is lighter and thicker, the structure is quite clear, and microfilament and microtubule in axon are clear. For 12 weeks after the operation, the experimental group shows more increase in the newly born nerve fibers, the myelin sheath has partial hyperplasia, which extrudes inward, even forms inner circle, the structure is clearer than before, but there is still some peeling-off. Whilst the control group shows there is more newly born fibers than that of the experimental group, the myelin sheath has partial hyperplasia, the structure is clear and regularly disposed, and the number of cell organ inside the axon is increased substantially.3 Muscular Histological Examination: biceps brachii sample from the right side is taken to measure the diameter of the cells, the cross sectional area of the muscular fiber and the remanet rate of the biceps brachii, the result shows the figures for the experimental group is lower than that of the control group, which is significant statistically.Conclusion: the results of this experiment illustrate: the nerve regeneration is closely related to the blood supply of the circumference, blood shortage not only delays the speed of the nerve regeneration, but also speed up the amyotrophy of the denervation muscle, it is harmful to the nerve regeneration and the function recovery. This is especially the case with the brachial plexus injury, because of its special anatomic feature, this kind of injury often comes with blood vessel injury, and leads to more handicap, thus it is especially important to heal the injured blood vessels as soon as possible and facilitate the nerve regeneration and function recovery.
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