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BACKGROUND:Previous studies have shown that traumatic brain injury can promote the regeneration of peripheral nerve by reducing scar collagen in nerve endings.OBJECTIVE:To investigate the effect of brain injury at different locations on the ipsilateral rat sciatic nerve regeneration.METHODS:Ninety-nine healthy male Sprague-Dawley rats were equivalently randomized into three groups:group A,right sciatic nerve transection;group B,right sciatic nerve transection combined with right brain injury;and group C,right sciatic nerve transection combined with left brain injury.All of transected nerves were sutured under microscope.Classical Feeney method was used to establish a model of traumatic brain injury.At 4,6,8,10 and 12 weeks after modeling,the sciatic functional index (SFI) was calculated by measuring footprint.At 4,8 and 12 weeks after modeling,the bilateral gastrocnemius were harvested for determining wet weight and calculate wet weight ratio,followed by acetylcholinesterase staining at the motor end plate to detect the absorbance values.At 4,8 and 12 weeks after modeling,fluoro-gold retrograde tracing was used to trace L4-5 vertebrae for 1 week,and the number of spinal cord anterior horn motor neurons positive for fluoro-gold was detected and calculated by fluorescence microscope.RESULTS AND CONCLUSION:The SFI value in each group was gradually improved with time.The SFI value was significantly higher in the groups B and C than the group A at 4 and 6 weeks after modeling (P ＜ 0.05),and was further improved in the group B at 8 weeks compared with the groups A and C (P ＜ 0.05).The wet weight ratio of gastrocnemius showed no significant difference among groups at 4 weeks after modeling (P ＞ 0.05),and the group B showed a significantly higher wet weight ratio than the other groups from the 8th week (P ＜ 0.05).Compared with the groups A and C,the absorbance values of motor endplate in group B appeared to be a significant increase at the beginning of the 8th week (P ＜ 0.05).At 4 and 6 weeks after modeling,the number of spinal cord anterior horn motor neurons positive for fluoro-gold was significantly nigher in the groups B and C than in the group A,and the number was significantly higher in the group B than the groups A and C at 12 weeks (all P ＜ 0.05).These finding manifest that brain injury can promote the repair of ipsilateral sciatic nerve injury,thus proving theoretical reference for unveiling the mechanism by which traumatic brain injury promotes peripheral nerve regeneration.
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This paper discussed the application of designing experiments from scientific research in Micro-biology courses and its effects on the teachers and students. The problems of the application of designing experiments in Microbiology courses were analyzed. The practice of the teaching reform showed that it give great advantages for the undergraduates with the enhancement of their ability on theory application and sci-entific innovation. This teaching reform could be widely popularized.