Muscle preservation in proximal nerve injuries: a current update.

Optimal recovery of muscle function after proximal nerve injuries remains a complex and challenging problem. After a nerve injury, alterations in the affected muscles lead to atrophy, and later degeneration and replacement by fat-fibrous tissues. At present, several different strategies for the preservation of skeletal muscle have been reported, including various sets of physical exercises, muscle massage, physical methods (e.g. electrical stimulation, magnetic field and laser stimulation, low-intensity pulsed ultrasound), medicines (e.g. nutrients, natural and chemical agents, anti-inflammatory and antioxidants, hormones, enzymes and enzyme inhibitors), regenerative medicine (e.g. growth factors, stem cells and microbiota) and surgical procedures (e.g. supercharge end-to-side neurotization). The present review will focus on methods that aimed to minimize the damage to muscles after denervation based on our present knowledge.

EFFECT OF BONE MARROW ASPIRATE IN DENERVATION-INDUCED SKELETAL MUSCLE ATROPHY.

OBJECTIVE: The aim: To evaluate muscle changes after sciatic nerve damage with the injection of bone marrow aspirate cells. PATIENTS AND METHODS: Materials and methods: 36 rabbits underwent sciatic nerve cross-section and neuroraphy, bone marrow aspirate cells were injected directly or 7 weeks after neuroraphy. Changes in skeletal muscle morphology (photomicrographs of histological sections were analyzed for morphometric analysis of collagen region, quantitative analysis of conducted collagen density and measurement of muscle fibers diameter) and biochemical parameters (catalase activity, superoxide dismutase and glutathione peroxidase measurements and level of TBARS was determined) at 8, 12, and 16 weeks were examined. RESULTS: Results: There is atrophy of muscle fibers in denervated muscles, and it has a negative tendency between 8 and 12 weeks. Delayed bone marrow aspirate cells injection into the muscles at 7 week - delayed atrophy and formation of TBA reactive substances. But bone marrow aspirate cells injection into the muscles directly after neuroraphy increased collagen formation, and development of fibrosis in areas of atrophy. CONCLUSION: Conclusions: Sciatic nerve injury results in atrophy of muscle tissue, which is partially delayed after delayed bone marrow aspirate cells injection at week 7. Muscle atrophy was characterized by a sharp increase in TBARS levels at 12 and 16 weeks and catalase activity at 12 weeks, and changes in biochemical parameters were partially normalized after the use of cell aspirates, to a greater extent with delayed injection.