Effect of Microwave on GAP-43 Expression in the Spinal Cord after Sciatic Nerve Lesions in Rats
|School||Dalian Medical University|
|Course||Rehabilitation Medicine and Physical Therapy|
|Keywords||Microwave Sciatic nerve lesions Rats GAP-43 SFI|
Objective: In order to investigate the mechanism of microwave effects on changing of GAP-43 expression in the spinal cord and promoting the regeneration of peripheral nerves, we set up the model of injured the right sciatic nerves of rats, studied the injured nerves histologically and functionally after irradiation. Peripheral injured nerve in patients with early stage of microwave treatment can improve the symptoms and the prognosis, and provide a theoretical basis.Methods: The right sciatic nerves of 64 male adult SD rats were crushed with forceps. They were randomly divided into 2 groups: the microwave treated group and the operative control group. Each groups divided into the 3th、7th、14th and 28th day postoperation groups. Then the rats of the microwave treated group were fixed on a table prostrated and the injured part were exposed to microwave at 6W for 6min each treatments, 5 days each weeks from 1 day after operation to the sacrifice day. The rats of the control group were also fixed on a table prostrated at same time, but were not exposed to microwave. We observed the general view of rats, analyzed the SFI index and the GAP-43 protein number by immunohistochemical staining and image analysis system. All dates were analyzed statistically.Results:1.General view: 5 rats had piece of ulcer at heel or toes in the control group, that none of rats had in the microwave treated group.2. The analysis of SFI: The SFI index in the microwave treated group rose obviously on 14th day postop, that in the control group rose on 21th day postop. The SFI index on 14th、21th and 28th day postoperation groups of the microwave treated group was significantly higher than that in the control group. (P<0.01).3. The immunohistochemical staining: The right sciatic nerves injured of rats is visible on the GAP-43 immune positive product in the damage side waist pulp crosscut slice of each groups, especially in the dorsalhorn substantia gelatinosa and abdominal, white matter in the most obvious horn dyeing light. GAP-43 immune positive cells of spinal cord showed polygons, triangular and performance, mainly in the neurons, renewable schwann cells and glial cells, in addition dyeing weight. GAP-43 protein expression on the 3th day immunological reaction strengthened, on the 7th day the immune positive cells reached the peak and on the 14th day slightly diminished, but still higher than the control group, on the 28th day the immune positive cells significantly reduced, immunological reaction dyeing weight. The control group on the 14th day the immune positive cells reached the peak, and on the 14th day slightly diminished. GAP-43 protein expression in the spinal cord increased after sciatic nerve injured. GAP-43 protein expression on 3th、7th and 14th day postoperation groups of the microwave treated group was significantly more than that in the control group((P<0.01,P<0.01,P<0.05).Conclusions: Microwave had obviously effects on the regeneration and functional recovery of the injured peripheral nerves after irradiation early. The mechanism included: 1. Microwave could improve the local blood circulation of the injured nerves in order to increasing the absorption of oedema and accelerating the metabolism. 2. Microwave could recovery the injured nerves and speed up the regeneration of tissue. 3. Microwave could enhance the early expression of GAP-43 protein and maintain its high level for long time in order to induce, stimulate and regulate axons growth and myelin sheath formation. It could also improve the speed of regeneration in the injured nerves.