| Spinal cord injury(SCI) is a common injury in the traumatology. SCI often causes quadriplegia and paraplegia, influences the people's life quality, and severely damages the human health. It is a great problem for the medical staffs to decrease the secondary SCI, accelerate the regeneration of spinal nerves, and regain the nervous function. The electric stimulation therapy has a long history, and gained very good effect. This test use the rat model, and the reverse transcription (RT) method to measure the expression of all kinds of nitricoxide synthase(NOS) mRNA.All the 30 rats are male, weighs between 210-260gs, randomly divided into 3 groups: electric stimulation(ES) group, model group, and control group. Electric stimulation and model group use the modified Allen's vertical hammer method with the strength of 5g×10cm to achieve moderate SCI(T10), injury diameter 2.5mm. After established the models, give the ESgroup pulse electric stimulation after 2hs, 30 minutes each time, one time per day. No treat to the model and control group. All the animals was put to death in strict aseptic condition when 1, 4, 24, and 48 hours posttrauma, cut out 1.5cm long spinal cord, making into homogenate, and then measure the expression of the NOS mRNA with RT-PCR. The results shows that there is expression of nNOS mRNA in normal condition, and the expression levels were all raised at 1,4, and 24 hours post SCI, the peak was at 1 hour, and decreased after that, returned to normal at 48 hours post SCI. The expression of all the ES groups except the 48h group was statistically less than that of the model groups. There is no statistically difference between the 24h and 48h ES groups and the control groups. There is no iNOS mRNA expression in 1 and 4 h post SCI and control groups, only little expression in 24h post SCI group, and increased expression in 48h post SCI group. There is no iNOS mRNA expression in 24h ES group, and the expression in 48h group was sharply decreased than that of the control group. There is no obvious influence of electric stimulation to theexpression of eNOS mRNA.NO is an unstable highly diffused free radical, and the biological function was mainly brought about by many chemical reactions, widely influencing the information conducting processes, energy metabolism and DNA synthesis. In physical condition, NO acts as the vasodilator, increasing the spinal cord blood flows, but the expression of NOS post SCI and the secondary elevation of NO take part in the pathological process of secondary SCI, and induce the elevation of glutamic acid and aspartic acid, aggravating the secondary SCI.The formation of NO in central nervous system is catalyzed by NOS. NOS is the only restriction enzyme. Since the half life of that was too short, NO was not easy to research directly, so it is usually to measure the activity of NOS to reflect the synthesis of NO. There are 2 kinds of NOS in central nervous system, cNOS and iNOS. The activity of cNOS depends on the Ca2+ and calcium modulating albumin (CMA), and reacts to the environmental stimulation rapidly, generating large amount of NO in short time, that may play an importantrole in the early stage after SCI. The function of cNOS in SCI is not clear. The cNOS includes nerve NOS (nNOS) and endothelium NOS (eNOS). There are great difference of the function of both of them in tissue injury. nNOS was considered to induce the neurotoxicity in early stage post CNS injury.Electric stimulation is a kind of therapy of SCI, and the mechanism is not clear. The mechanism of pulse stimulation to treat SCI may be: a, pulse stimulation lead to effective polarization of neurons, and reach the same effect as that of the direct current. Meanwhile, since the nerve fibers gain active moves, increase the enzyme activity of neurons, the transportation of axons, and the metabolism, and they are good to regeneration, b, the pulse stimulation can increase the growth and regeneration of nerve fibers post SCI, and change the function state of neurons, c, it can wake up the shock or dormant spinal cord post SCI.This test results show that: the early electric stimulation therapy can decrease the expression of nNOS mRNA, iNOS mRNA, the activity of NOS, and the generation of NO, but no...
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