Effectiveness Of Targeted Nerve Functional Replacement On Reconstructing Motor Function

Objective: To establish a rat model using Targeted Nerve Functional Replacement(TNFR),and use physiology,behavior,and histology to explore the effect and mechanism of TNFR technology to reconstruct motor function.Methods: In this study,30 SD rats were randomly divided into control group,denervation group.TNFR groups were divided into TNFR group,TNFR delayed 2 weeks group and TNFR delayed 4 weeks group according to the timing of nerve anastomosis.The right side of each group of rats was used as the surgical side,the right median nerve and the musculocutaneous nerve were anastomosed,and the recording electrode was implanted into the biceps;the left side was used as the control side,only the recording electrode was implanted,and the rest was not treated.TNFR technology was used to anastomosis the target nerve with the targeted nerve.Implanted electrode were used to collect the myoelectric signals during exercise.Time domain method,average rectified value(ARV)was used to analyze the results of myoelectric signals;the "Grooming Test" was used to evaluate the function of the forelimb;The muscle force analysis was used to detect the maximum single contractility and maximum tonic contraction;muscle wet weight maintenance rate(%)= right muscle weight / left muscle weight x 100% was used to evaluate muscle atrophy after 4 weeks of surgery;Gold chloride staining of skeletal muscle was used to assess the changes in motor endplates.Results: 1.The myoelectric signals of the rats were successfully recorded by the implanted electrode following the surgery.Rats in each group of TNFR obtained stable EMG signals at the first week.The ARV of rats in each group of TNFR showed an increasing trend in time series,and the fourth week was significantly greater than the first week(P <0.01);The ARV on the operative side of the TNFR group at week 1st and week 4th was greater than the ARV of the TNFR delayed 2 and 4 week groups(P <0.05);The ARV of the TNFR delayed 2 weeks group was stronger than that of the TNFR delayed 4 weeks group(P <0.05).The ARV of the biceps brachii on the left control side of each group of rats did not change significantly within 1st to 4th weeks,and there was no statistically signifi-cant difference between Week 1st and Week 4th(P> 0.05);2.The evaluation results of "Grooming Test" indicated that the surgical side of rats of control group were rated 5;the TNFR groups were rated 4 on the surgical side,the differences were sta-tistically significance on the surgical side compared with the control group(P <0.01);the evaluation result of the surgrical side of the denervated group was grade 1;3.The maximum single contractile force and maximum tonic contractile force of the biceps brachii on the surgical side of the control group were significantly greater than those of the TNFR groups,and there were significant differences between each group(P <0.01);the maximum single contraction force and maximum tonic contraction force of the TNFR group on the surgical side were significantly greater than those of the TNFR delayed 2 week group(P <0.01);the TNFR delayed 2 week group rats were stronger than those of TNFR delayed 4 week group(P <0.05);4.The wet weight maintenance rate(100%)of the biceps brachii muscle on the surgical side of the normal control group was significantly greater than the results of the other groups(P <0.01);the surgical side of the TNFR group was significantly greater than the results of the TNFR delayed 2 week group and the TNFR delayed 4 week group(P <0.01);the surgical side of TNFR delayed 4 weeks group was significantly greater than that of denervation group(P <0.01);5.Four weeks after the operation,the structurally complete motor endplates can be detected on the surgical side of each group of TNFR rats,and the structural integrity is significantly higher than the surgical side of the denervated group;the number is greater than the surgical side of the denervated group(P <0.05),but still smaller than the surgical side of the control group(P <0.05).Conclusion: TNFR technology can effectively use the neural network of the targeting nerve to reconstruct motor function of the target nerve,short the rehabilitation time following surgery,and enhance effect of rehabilitation of functional reconstruction after denervation,and provide a complete TNFR animal model.