K.R. Byrnes 1, R.W. Waynant 2, I.K. Ilev 2, B. Johnson 1, Pollard H. 1, Srivastava M. 1, Eidelman O. 1, Huang, W. 1, J.J. Anders1
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, MD, USA;
- Center for Devices and Radiological Health, Food and Drug Administration, Rockville, MD, USA
Secondary injury in the spinal cord, which results in axonal degeneration, scar and cavity formation and cell death, occurs around the site of the initial trauma and is a primary cause for the lack of axonal regeneration observed after spinal cord injury (SCI). The immune response after SCI is under investigation as a potential mediator of secondary injury. Treatment of SCI with 810 nm light suppresses the immune response and improves axonal regeneration.
We hypothesize that these beneficial effects observed in the injured spinal cord are accompanied by alterations in gene expression within the spinal cord, particularly of those genes involved in secondary injury and the immune response. To test this hypothesis, a dorsal hemisection at vertebral level T9 was performed. The injured spinal cord from rat was then exposed to laser light (810nm, 150mW, 2,997 seconds, 0.3cm2 spot area, 1589 J/cm2) and spinal cord samples, including the injury site, were harvested at 6 and 48 hours and 4 days post-injury. Total RNA was extracted and purified from the lesioned spinal cord and cDNA copies were either labeled with [32P] for microarray analysis or amplified and analyzed with a polymerase chain reaction (PCR).
Microarray results revealed a suppression of genes involved in the immune response and excitotoxic cell death at 6 hours post-injury, as well as cell proliferation and scar formation at 48 hours post-injury in the light treated group. Analysis of the PCR products revealed that light treatment resulted in a significant suppression of expression of genes that normally peak between 6 and 24 hours post-injury, including the pro-inflammatory cytokine interleukin 6 (IL6), the chemokine monocyte chemoattractant protein 1 (MCP-1) and inducible nitric oxide synthase (iNOS; p<0.05). Genes expressed earlier than 6 hours post-injury, such as IL1b, tumor necrosis factor a (TNFa) and macrophage inflammatory protein 1a (MIP-1a) were not affected by light treatment.
Although the precise role some of these genes play in axonal regeneration after spinal cord injury is currently unclear, these data demonstrate that light therapy has an anti-inflammatory effect on the injured spinal cord, and may reduce secondary injury, thus providing a possible mechanism by which light therapy may result in axonal regeneration.
[World Association for Laser Therapy]
- Thermographic study of Low Level Laser Therapy for ACUTE-PHASE INJURY
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- The interauricular laser therapy of RHEUMATOID ARTHRITIS.
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- Diode Laser In CERVICAL MYOFASCIAL Pain: A Double-Blind Study Versus Placebo
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- Successful Management Of Female Office Workers With "REPETITIVE STRESS INJURY" Or "CARPAL TUNNEL SYNDROME" By A New Treatment Modality Application Of Low Level Laser
- The use of infrared laser therapy (LLLT) in the treatment of VENOUS ULCERATION
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- Low level laser therapy (LLLT) in ambulatory patients with VENOUS STASIS ULCERS
- The use of low energy photon therapy (LEPT) in VENOUS LEG ULCERS: a double blind, placebocontrolled study
- The effect of infr-ared laser irradiation (LLLT) on the duration and severity of POSTOPERATIVE PAIN: a double blind trial
- Effects of phototherapy (LLLT) on pressure ULCER HEALING in elderly patients after a falling trauma. A prospective, randomized, controlled study.
- The use of low intensity laser therapy (LLLT) for the TREATMENT OF OPEN WOUNDS in psychogeriatric patients: a pilot study.
- Can low reactive-level laser therapy (LLLT) be used in the treatment of NEUROGENIC FACIAL PAIN? A double-blind, placebo controlled investigation of patients with trigeminal neuralgia
- Clinical application of GaAlAs 830nm diode laser (LLLT) in treatment of RHEUMATOID ARTHRITIS