ABSTRACT
BACKGROUND: Microscopic surgery or some adjuvant treatments can neither effectively delay nor treat denervated muscle atrophy by repairing damaged nerve cells. Studies have found that bone marrow mesenchymal stem cells have the potential for directional differentiation and repair damaged tissues under certain environmental factors. It is speculated that the cells can play a certain role in repairing denervated atrophic muscles. OBJECTIVE: To investigate whether transplantation of bone marrow mesenchymal stem cells can alleviate and retard atrophy of denervated muscles. METHODS: Primary bone marrow mesenchymal stem cells were isolated from Sprague-Dawley rats, and passage 3 cells were labeled by BrdU for cell transplantation. Thirty Sprague-Dawley rats were divided into three groups, 10 rats in each group. In the sham operation group, only the main trunk of the sciatic nerve was exposed but not clamped. In the treatment group, the main trunk of the sciatic nerve was clamped and bone marrow mesenchymal stem cell suspension was injected into the gastrocnemius muscle. In the control group, after the sciatic nerve trunk was clamped, the gastrocnemius muscle innervated by the sciatic nerve was injected with DMEM medium of equal volume (without cells and fetal bovine serum). Basso, Beattie and Bresnahan scores were used to evaluate the motor function of the rat’s left hindlimb at 1 and 2 weeks after cell transplantation. Changes in the gastrocnemius muscle fibers were observed by hematoxylin-eosin staining and BrdU immunohistochemical staining at 14 days after cell transplantation. RESULTS AND CONCLUSION: The passage 3 bone marrow mesenchymal stem cells were positive for BrdU. The labeled cells could survive in and repair the denervated muscle tissue in the treatment group. Compared with the model group, the denervated muscle fibers of the treatment group recovered from mutual fusion and re-arranged regularly. To conclude, transplantation of bone marrow mesenchymal stem cells can alleviate and retard atrophy of denervated muscles.
ABSTRACT
Objective To delay the atrophy of denervated skeletal muscle by baby-sitting in reverse end-to-side fashion and explore the feasibility of this operation to improve the recovery of denervated muscle in rats.Methods From July,2015 to March,2016,32 female SD rats were divided into 4 groups randomly and the tibial nerve of each rats was transected.In immediate repair group,the transected tibial nerve was sutured in situ.In unprotected group,the tibial nerve stump was putting-aside.The sural nerve was transected in other 2 groups.The proximal sural nerve was connected to the distal tibial nerve stump directly in end-to-end (ETE) protected group and to the side of the distal tibial nerve stump in end-to-side (ETS) protected group.After 3 months,connected the two ends of tibial nerve except immediate repair group.After another 3 months,the tibial nerve functional index,electrophysiological testing,histology and morphology were examined.Results The gastrocnemius muscle was atrophy obviously in unprotected group,while in other groups the muscle structure was well protected.The tibial nerve functional index (-39.54±24.32),motor nerve conduction velocity[(30.25±12.65)m/s],and muscle contraction [(0.98 ± 0.38)N)] indicated that the gastrocnemius muscle function in ETS protected group was statistically better recovery than in unprotected group [-75.65±32.13,(24.93±8.69)m/s and (0.64±0.20)N,respectively] and ETE protected group [-62.34± 21.65,(16.90±7.92)m/s and (0.75-±0.15)N,respectively](P＜0.05).The contractility of muscle were poor recovery in ETE protected group,which was similar to unprotected group(P＞0.05).Conclusion Sensory nerve baby-sitting in reverse end-to-side fashion is a effective method to improve the recovery of denervated muscle in rats.
ABSTRACT
Analysis of insertional activity is a routine part of the clinical electromyogrphic examination. It provides an information of muscle excitability but it's clinical significance has not perfectively accepted yet. This study was designed to evaluate clinical usefulness of insertional activity through quantitative analysis in the diagnostic field of pathology. Monopolar needle electrode was inserted briefly in the biceps brachii, paralumbar spinal and tibialis anterior muscles of the normal and denervated muscles. Total duration and spike duration of the insertional activity were measured 10 times in each muscle and averaged. Within spike duration we measured turns, mean amplitude, turns/amplitude, RMS, mean frequency and median frequency. The measured parameters of insertional activities were not significantly different according to the muscle in normal controls. In denervated muscles, the turns, mean amplitude, RMS, mean frequency and median frequency were decreased but turns/amplitude was increased compared to those of normal controls. But there were no difference in total duration and spike duration between normal and denervated muscles. In denervated muscles the muscle power was positively correlated with turns, mean amplitude, RMS, mean frequency and median frequency, and the grade of abnormal spontaneous activities was inversely correlated with turns, mean amplitude, RMS, mean frequency and median frequency. Therefore quantitative analysis of insertional activity could be a useful method for the diagnosis of neuromuscular disease.