Rosner M, Caplan M, Cohen S, Duvdevani R, Solomon A, Assia E, Belkin M, Schwartz M
Goldschleger Eye Research Institute, Sackler School of Medicine, Tel Aviv University, Tel Hashomer, Israel.
Lasers Surg Med. 1993;13(6):611-7. doi: 10.1002/lsm.1900130604.
Low-energy laser irradiation has been reported to postpone the degenerative processes in crushed optic nerves of rats, which are part of the nonregenerable mammalian central nervous system. In the present study, we evaluated the optimal irradiation parameters for this purpose. Optic nerves of 141 rats were subjected to crush injury and then irradiated through the eye, starting at different points of time before or after the injury, for different durations and periods, using various intensities of either helium-neon laser or noncoherent infrared light (904 nm). The effect was evaluated by measurements of the compound action potentials of the nerve segments between the site of injury and the optic chiasm. The compound action potential amplitude of the crushed nonirradiated nerves, as measured 2 weeks after the injury, was found to be 0.51 +/- 0.30 mV, in contrast to 3.10 +/- 1.03 mV measured in 232 normal nerves. Irradiation with a 10.5 mW helium-neon laser for 2 and 3 min once a day for 14 consecutive days resulted in maximal preservation of action potentials (1.78 +/- 0.72 and 1.95 +/- 0.71 mV, respectively). Irradiations beginning immediately prior to the injury were as effective as irradiations beginning soon after it. Irradiations for longer than 3 min or twice a day aggravated the damage. Noncoherent infrared light was ineffective or adversely affected the injured nerves. Our experiments suggest that optimal delay of posttraumatic optic nerve degeneration in rats is attainable with 10.5 mW helium-neon laser irradiations for 2 or 3 min once a day for 14 consecutive days.
据报道，低能量激光照射可延缓大鼠视神经挤压伤后的退行性变过程，而大鼠视神经属于不可再生的哺乳动物中枢神经系统的一部分。在本研究中，我们评估了实现此目的的最佳照射参数。对141只大鼠的视神经进行挤压损伤，然后通过眼睛进行照射，在损伤前或损伤后的不同时间点开始，使用不同强度的氦氖激光或非相干红外光（904 nm），照射不同的持续时间和周期。通过测量损伤部位与视交叉之间神经节段的复合动作电位来评估效果。损伤后2周测量发现，挤压但未照射的神经的复合动作电位幅度为0.51±0.30 mV，相比之下，232条正常神经测量值为3.10±1.03 mV。连续14天每天用10.5 mW氦氖激光照射2分钟和3分钟，可最大程度地保留动作电位（分别为1.78±0.72和1.95±0.71 mV）。在损伤前立即开始照射与损伤后不久开始照射效果相同。照射超过3分钟或每天照射两次会加重损伤。非相干红外光无效或对受损神经产生不利影响。我们的实验表明，连续14天每天用10.5 mW氦氖激光照射2分钟或3分钟，可实现大鼠创伤后视神经退变的最佳延迟。
