| Brachial plexus injury is one of the most common deafness of the peripheral nerve injury,especially roots avulsion often cause upper limb movement,sensory dysfunction that seriously affect the quality of life of patients.How to reduce and improve the upper limb movement and sensory dysfunction of patients that is the focus of clinical research at home and abroad.At present the main measures to treatment of brachial plexus injury are surgical and drug treatment,these treatments can make the patient’s shoulder and elbow function partially restor but the patient forearm,wrist and hand symptoms are not significantly alleviated.The reason is that injury after a few minutes of injury,the body immediately programs a series of "waterfall" type of biochemical reactions,such as microvascular system damage,inflammatory response,free radical production,excitatory amino acid Release,lipid peroxidation(LP),nerve fiber demyelination and glial scar formation,in which the secondary injury caused by oxidative stress is one of the main factors that lead to poor recovery of motor and sensory function after limb root avulsion.Oxidative stress is an imbalance between oxidation and antioxidant systems in the internal environment that lead free radicals to increase and / or reduced ability of clearance.Too much oxygen free radicals(ROS)in tissues or cells that accumulate and initiate oxidative chain reactions,such as lead proteins,lipids and DNA loss of biological activity or degradate,inhibition of mitochondrial function,ion balance disorders and excitability toxicity etc.These eventually lead neuronal to death.At the same time,the body launched a variety of defense systems to resist oxidative stress.Nrf-2 is one of the transcription factors that regulates cells against oxidative stress in internal and external environment.In physiological state,most of the Nrf-2 binds to Keap1 which is inactive.After the stimulation oftrauma and inflammation Nrf-2 dissociates from Keap1 and transfers from cytoplasm to nucleus and regulates the expression of phase II detoxification enzyme,antioxidant enzyme,anti-inflammatory factor and calcium ion regulating protein etc.HO-1 is an inducible enzyme in the body,which can decompose heme and reduce its damage to cells and consume free oxygen in the body,thereby reducing the generation and accumulation of oxygen free radicals.Studies have shown that up-regulation of Nrf-2-ARE pathway can reduce free radicals in ischemia and hypoxia and accelerate the removal of free radicals and restore intracellular oxidation and steady state between antioxidant system and reduce the damage to body tissues and cells.Thus,activation of the Nrf-2 / ARE pathway may be a new target for the treatment of brachial plexus injury.In this study,HE staining was used to detect the survival rate of spinal anterior horn motor neurons after brachial plexus roots avulsion to determine the effect of brachial plexus roots avulsion to motor neurons in spinal anterior horn.The expressions of Nrf-2 and HO-1 in the anterior horn of the spinal cord were observed by q PCR and immunoblotting at different time points after brachial plexus root avulsion.To investigate the temporal significance of expression of Nrf-2-ARE pathway after brachial plexus root avulsion.It was expected to provide a new target and theoretical basis for clinical treatment of brachial plexus root avulsion by antioxidation.Objective:To observe the survival rate and the temporal changes of Nrf-2 and HO-1expression in the forearm motor neurons of the brachial plexus roots avulsion at different time points.It was expected that could provide a new target and theoretical basis to treatment of brachial plexus root avulsion.Method:1 Preparation of rat plexus roots avulsion modelThe rat model of brachial plexus roots avulsion was established by reference to Zheng Sheng Nai and others’ cervical approach.2 Determination of indicators and inspection methodsThe changes of morphological structure and survival rate of motor neurons in injured spinal cord anterior horn were observed by HE staining.Western blot and qPCR were used to detect the expression of Nrf-2 and HO-1in the injured spinal cord anterior horn of rats.Result:1 general observationAll the model rats were generally in good condition and all show partial paralysis of the upper right part of the limbs,left upper limb activity were normal,the animals did not appear lower limb paralysis or defecation disorders and other performance.2 The morphology and survival rate of motor neurons in spinal anterior horn of ratsThe morphological changes of motor neurons in spinal anterior horn of rats: the spinal cord tissue of the normal control group showed that the interface of the gray matter and white matter of the spinal cord anterior horn was clear,the structure was clear and the axon was arranged;no bleeding,edema,motor neuron was abundant and the cell morphology was normal,nissl was clearly visibled.Surgical avulsion of the spinal cord: At all time points after surgery on the side of the white matter obvious edema,a large number of vacuoles,axons twiste part of the fracture;the bleeding stove were visibled scatterely,spinal anterior horn motor neurons decreased or even missing,nucleus unclear,nucleus nissinia disappeared,cytoplasm concentration,staining deepened.In addition,telescopic motor neurons could be seen.The motor neuron count and survival rate in the spinal anterior horn of rats: the statistical analysis found that survival rate of spinal cord anterior horn motor neurons in each control group was not significantly different.In the control group,brachial plexus injury 1 h,3 h,6 h,12 h,24 h,2 d,3 d,The survival rate of motor neurons in the anterior horn of spinal cord was significantly different.There was no significant difference in the survival rate of spinal anterior horn motor neurons between the brachial plexus injury group and the control group at 1 h,3 h,6 h,12 h,24 h and 2 d.Compared with thecontrol group,the survival rate of brachial plexus injury group at 3 d,7 d was significantly lower,statistically significant.3 The changes of Nrf-2 and HO-1 in motor neurons of injured spinal cord anterior horn in ratsThe expression of Nrf-2 and HO-1 was observed at all time points after brachial plexus root avulsion,and the expression showed a certain gradient with the prolongation of injury time.The expression of Nrf-2 protein in the anterior horn was significantly decreased;The expression of Nrf-2nucleoprotein and HO-1 increased gradually after brachial plexus root avulsion injury,the expression of Nrf-2 nucleoprotein was the highest at 1 d after injury,decreased at 2 d,decreased significantly at 7 d,and the expression of HO-1 was the highest at 1-2 d after injury,decreased at 3 d,decreased significantly at 7 d.The expression of Nrf-2 mRNA and HO-1 mRNA in the anterior horn of the brachial plexus was similar to the protein,and the expression of Nrf-2 mRNA and HO-1 mRNA in the brachial plexus root increased gradually after injury,and reached the highest at 24 h and 1-2 d after injury,then decreased at 7 d.Conclusion:1 The rat model of brachial plexus roots avulsion was established by cervical and thoracic approach.2 The survival rate of the motor neurons in the anterior horn of the spinal cord gradually decreased with the prolongation of time.3 The expression of Nrf-2 and HO-1 after the brachial plexus root avulsion gradually increased and reaches the peak at 1 d and 1-2 d,and then decreased gradually.4 The involvement of Nrf-2-ARE pathway in spinal cord anterior horn after brachial plexus roots avulsion injury would will provide a new target and theoretical basis for the treatment of brachial plexus root avulsion by antioxidation. |
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