| Part I Making MCAo Rats Model by ElectrocoagulationObjective: To build the model of rats with middle cerebral artery occlusion(MACo),to observe and record the behavioral alteration in the model rats,and to confirm the infarction size by pathological examination.Methods: Twenty-four SD rats were randomly divided into experimental group and control group with 12 rats in each group.All rats began the behavioral training 3 days before the operation.The left middle cerebral arteries of all rats were exposed by Tamura method,but only rats in the experimental group had their arteries occluded between inferior cerebral vein and olfactory tract by electrocoagulation.All rats were graded for their behaviors,and the tests included rotating rod test,beam balance test and elevated body swing test.After that,the rats were executed to take out the brain tissue to conduct TTC stain.Results: In the experimental group,11 out of 12 rats were successfully made into models of MCAo with 9 getting 2 points of Longa evaluation and 2 getting 3 points,and 1 died of overdose anesthesia.None of the rats had complications of difficulty in eating or temporomandibular joint disturbance.No rats in the control group got neurological dysfunction or behavioral disorders.In the respect of the behavioral tests 24 hours after the operation,the roller residence time of control group(160.92±5.76s)was longer than the time of experimental group(32.64±4.30s).In the balance beam test,The score of control group(6.00±0.00 分)was higher than the score of experimental group(2.82±0.60 分).In the dangling rotation test,the mean percentage of deflection to the right for elevated body swing test of control group(50.83%±3.24%)was lower than experimental group(92.73%±5.79%).TTC stain showd that the infarction involved the dorsolateral cerebral cortex,including the motor cortex.Conclusion: The MCAo rat model by electrocoagulation has good homogeneity,low mortality and is more close to the clinical situation.PART II: The effect and mechanism of Motor cortex stimulation on the recovery of motor function in MCAo Rat modelObjective To observe the behavior changes and microtubule associated protein-2(MAP-2)expression of SD rats implanted stimulating electrode on the left side of the motor cortex.Methods 24 MCAo rats were randomly divided into stimulation group and control group,with 12 for each group.The rats in stimulation group were stimulated by electric(frequency 50 Hz,pulse width 200μs and current 100μA)1 hour per day for 2 weeks.Behavioral tests were conducted at the day1,day5,day10,and day15,the control group did not perform electrical stimulation.The expression of MAP-2 in the brain was explored by Immunofluorescence staining at day 15.Results(1)In the turn great tests,roller residence time was not statistically significant different between stimulation group(35.25±5.29s)and control group(35.33±4.85s)at day 1.The roller residence time of stimulation group at day 5(63.67±8.18s),day10(86.42±9.92s),and day 15(112.33±7.98s)were longer than the time of control group(respectively,45.33±5.69 s,67.25±5.79 s,84.75±8.47s).In the balance beam test,the score was not statistically significant different between stimulation group(2.58±0.67)and control group(2.75±0.62)at day 1.The score of stimulation group at day 5(3.75±0.62),day10(4.67±0.78),and day 15(5.17±0.18)were higher than the time of control group(respectively,3.08±0.67,3.58±0.79,4.33±0.89).Besides,in the dangling rotation test,the percent of right deflection was not statistically significant different between stimulation group(93.67%±2.53%)and control group(92.50%±2.75%)at day 1.The score of stimulation group at day 5(77.83±7.96%),day10(70.17%±5.89%),and day 15(59.92%±7.83%)were lower than the time of control group(respectively,85.50%±5.81%,77.58%±7.63%,71.42%±5.65%).(2Immunofluorescence staining indicated that the expression of MAP-2 in the stimulation group was 39.33%±2.96% which was higher than that in control group(14.00%±1.73%).Conclusion MCS might promote the recovery of motor function after stroke via the expression of MAP-2 which is likely to be related to change of synaptic substructure and increased synaptic plasticity. |
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