Bibikova A, Oron U
Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel.
Anat Rec. 1995 Jan;241(1):123-8. doi: 10.1002/ar.1092410116.
It is known that while denervated skeletal muscles have the ability to regenerate, maturation of regenerated myofibres does not take place under these conditions. Denervation also causes elevation of "invasive" and satellite cells, but the role of these cells in the regeneration process after injury to the denervated muscle is still unknown. Low energy lasers have recently been found to modulate and accelerate physiological processes in cells. The aim of the present study was to compare regeneration in denervated and innervated amphibian muscles and to investigate whether this process in denervated muscles can be stimulated by low energy laser irradiation prior to injury in these muscles.
Denervated gastrocnemius muscles of toads were irradiated with He-Ne laser (6.0 mW, 31.2 J/cm2) 7 days postdenervation (control muscle received red light irradiation at the same wavelength). Nine days after denervation cold injury was performed on the site of irradiation of both groups of muscles. At 14 days postinjury all muscles were removed and processed for histology and histomorphometric analysis of mononucleated cells, myotubes, and young myofibres in the regenerated zone.
The volume fraction (percent of total injured zone) of the various histological structures in the injured zones 14 days after cold injury in the denervated (9 days prior to injury) muscles did not differ from innervated injured muscles at the same time interval postinjury. The mononucleated cells and myotubes in the laser irradiated muscles comprised 49 +/- 4% and 6 +/- 1% of the injured area, respectively, which was significantly lower than their volume fraction (67 +/- 2% and 11 +/- 2%, respectively) in the control muscles. The young myofibres populated 34 +/- 4% of the total injured area in the denervated and laser irradiated muscles which was significantly higher than their volume fraction (12 +/- 2%) in control denervated muscles.
It is concluded that initial stages of regeneration can also take place in skeletal denervated and injured muscles of amphibians. The kinetics of the regeneration process are identical in denervated and innervated muscles. The process of regeneration in denervated muscles can be markedly enhanced if the muscle is irradiated by low energy laser prior to injury, probably by activation (stimulation of proliferation and/or differentiation) cells in the muscles that are "recruited" and participate in the process of regeneration.
已知失神经支配的骨骼肌具有再生能力，但在这些条件下再生肌纤维不会成熟。去神经支配还会导致“侵入性”细胞和卫星细胞增加，但其在失神经支配肌肉损伤后再生过程中的作用仍不清楚。最近发现低能量激光可调节和加速细胞中的生理过程。本研究的目的是比较失神经支配和有神经支配的两栖类肌肉的再生情况，并研究在这些肌肉损伤前进行低能量激光照射是否能刺激失神经支配肌肉的再生过程。
蟾蜍失神经支配的腓肠肌在去神经支配7天后用氦氖激光（6.0 mW，31.2 J/cm²）照射（对照肌肉接受相同波长的红光照射）。去神经支配9天后，对两组肌肉的照射部位进行冷损伤。损伤后14天，取出所有肌肉并进行组织学处理，对再生区域的单核细胞、肌管和年轻肌纤维进行组织形态计量分析。
在失神经支配（损伤前9天）的肌肉冷损伤14天后，损伤区域各种组织结构的体积分数（占总损伤区域的百分比）与损伤后相同时间间隔的有神经支配的损伤肌肉无差异。激光照射肌肉中的单核细胞和肌管分别占损伤面积的49±4%和6±1%，显著低于对照肌肉中的体积分数（分别为67±2%和11±2%）。失神经支配且经激光照射的肌肉中年轻肌纤维占总损伤面积的34±4%，显著高于失神经支配对照肌肉中的体积分数（12±2%）。
得出结论，两栖类失神经支配和损伤的骨骼肌也能发生再生的初始阶段。失神经支配和有神经支配的肌肉再生过程的动力学相同。如果在损伤前用低能量激光照射肌肉，失神经支配肌肉的再生过程可能会显著增强，这可能是通过激活（刺激增殖和/或分化）被“募集”并参与再生过程的肌肉中的细胞来实现的。
