| Objective:Injuries of peripheral nerves have long been a common clinical problem. There is a important difference between the peripheral nerve and central nerve:The peripheral nerve can have a great degree functional recovery after surgical repair while the central nerve cannot. However, the functional recovery of injured nerve is unsatisfactory up to the present, for peripheral nerve regeneration involves a complex process of biochemical and cellular events and the microenvironment of the regenerating nerve influences its repairing results very much, and for its peculiar structure and function. Recent years, rehabilitation medicine has developed quickly and many studies about treating diseases with physical factors have been reported. Some experiments have showed that physical factor can improve the regeneration of injured peripheral nerve. But those experiments used to be using single physical factor, while doctors usually used combined physical factors to improve curative effects. This experiment made a nerve regeneration chamber model and simulated clinical therapy by using combined physical factors to improve the regeneration of injured peripheral nerve. One factor is decimeter wave and the other is electric stimulation. Its purpose was to probe into and reveal the mechanism of combined physical factors improving peripheral nerve regeneration, and then to provide theoretical basis for clinical applications. Methods : 60 Sprague-Dawley rats (200-250g) were randomly divided into 4 groups: group A, the electric stimulation group; group B, the decimeter wave group; group C, the combined physical factors group; group D, the control group. After anesthetized, the left sciatic nerve was exposed and was excised. Using a silicone tube to form a regeneration chamber bridged the two ends. A gap of 6mm was left between proximal and distal stumps. Then the rats of group A were fixed on a table prostrated and the left posterior thigh was stimulated by electric stimulation machine for 10 minutes every day from day 1 postoperation to the sacrifice day. The rats of group B were exposed to decimeter wave every day for 10 minutes from day 1 postoperation to the sacrifice day. The rats of group C were firstly exposed to decimeter wave for 10 minutes and then given electric stimulation machine for 10 minutes every day from day 1 postoperation to the sacrifice day. The rats of group D were not given any treatment. At the 1st, 2nd, 4th, 8th and 12th week postoperation, the left sciatic nerve were removed and anatomical, light and electron microscope observation, morphmetric analysis and S-100 protein immunochemical staining were performed. At the 12th week postoperation, electrophysiological assessment was conducted to measure the latency; nerve conduction velocity and amplitude of compoundmuscle action potentials and the SFI index were analyzed. All dates were analyzed statistically. Results:The anatomical observation: group B and C adhesion around repaired nerve were much looser then group A and D. The time of nerve stumps connecting together was shortest and the diameters were biggest in group C. Light microscope observation: the nerve's fiber and myelin sheath were the most in group C. More regenerating axons and myelin sheath formation were observed. The inflammatory cells infiltrating degree were lightest in group C. S-100 protein was most expressed in group C. The electron microscope observation: the nerve's morphous was the best in group C. The analysis of SFI: The SFI recovery rate in group C was significantly higher than that in group A, B, D. The SFI were 34.89±0.95 in group A, 35.33±0.38 in group B, 47.92±0.64 in group C, 24.67±0.49 in group D, respectively. (A-B P > 0.05, A -C P < 0.05, A-D P < 0.05,B-C P < 0.05, B-D P < 0.05,C-D P < 0.05). The electrophysiological assessment: the parameters [latency(ms), nerve conduction velocity(m/s) and amplitude (mv) of compound muscle action potentials] revealed a better trend in group C compared with that in group A , B, D. They were 2.44±0.16 m/s,35.40±0.75 m/s,4.97±0.16 mv in group A. 2.46±0.49 m/s,36.00±0.68 m/s,4.95±0.07 mv in group B. 1.74±0.44 m/s,45.30±1.41 m/s,6.53±0.07 mv in group C. 3.45±0.46 m/s,20.70±1.14 m/s,3.90±0.07 mv in group D. (A-B P > 0.05, A -C P < 0.05, A-D P < 0.05,B-C... |
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