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Light-Emitting Diode Photobiomodulation After Cerebral Ischemia
摘要： Photobiomodulation (PBM) therapy is a promising therapeutic approach for several pathologies, including stroke. The biological effects of PBM for the treatment of cerebral ischemia have previously been explored as a neuroprotective strategy using different light sources, wavelengths, and incident light powers. However, the capability of PBM as a novel alternative therapy to stimulate the recovery of the injured neuronal tissue after ischemic stroke has been poorly explored. The aim of this study was to investigate the low-level light irradiation therapy by using Light Emitting Diodes (LEDs) as potential therapeutic strategy for stroke. The LED photobiomodulation (continuous wave, 830 nm, 0.2–0.6 J/cm2) was firstly evaluated at different energy densities in C17.2 immortalized mouse neural progenitor cell lines, in order to observe if this treatment had any effect on cells, in terms of proliferation and viability. Then, the PBM-LED effect (continuous wave, 830 nm, 0.28 J/cm2 at brain cortex) on long-term recovery (12 weeks) was analyzed in ischemic animal model by means lesion reduction, behavioral deficits, and functional magnetic resonance imaging (fMRI). Analysis of cellular proliferation after PBM was significantly increased (1 mW) in all different exposure times used; however, this effect could not be replicated in vivo experimental conditions, as PBM did not show an infarct reduction or functional recovery. Despite the promising therapeutic effect described for PBM, further preclinical studies are necessary to optimize the therapeutic window of this novel therapy, in terms of the mechanism associated to neurorecovery and to reduce the risk of failure in futures clinical trials.
关键词： magnetic resonance imaging,intracerebral hemorrhage,photobiomodulation therapy,ischemic stroke,functional recovery,animal model
更新于2025-09-12 10:27:22
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Optical Coherence Tomography Study of Retinal Changes in Normal Aging and After Ischemia
摘要： PURPOSE. Age-related thinning of the retinal ganglion cell axons in the nerve ?ber layer has been measured in humans using optical coherence tomography (OCT). In this study, we used OCT to measure inner retinal changes in 3-month-, 1-year-, and 2-year-old mice and after experimental anterior ischemic optic neuropathy (AION). METHODS. We used OCT to quantify retinal thickness in over 200 eyes at different ages before and after a photochemical thrombosis model of AION. The scans were manually or automatically segmented. RESULTS. In normal aging, there was 1.3-lm thinning of the ganglion cell complex (GCC) between 3 months and 1 year (P < 0.0001) and no further thinning at 2 years. In studying age-related inner retinal changes, measurement of the GCC (circular scan) was superior to that of the total retinal thickness (posterior pole scan) despite the need for manual segmentation because it was not contaminated by outer retinal changes. Three weeks after AION, there was 8.9-lm thinning of the GCC (circular scan; P < 0.0001), 50-lm thinning of the optic disc (posterior pole scan; P < 0.0001), and 17-lm thinning of the retina (posterior pole scan; P < 0.0001) in the 3-month-old group. Changes in the older eyes after AION were similar to those of the 3-month-old group. CONCLUSIONS. Optical coherence tomography imaging of a large number of eyes showed that, like humans, mice exhibited small, age-related inner retinal thinning. Measurement of the GCC was superior to total retinal thickness in quantifying age-related changes, and both circular and posterior pole scans were useful to track short-term changes after AION.
关键词： vision loss,optic neuropathy,aging,retinal ganglion cell,optical coherence tomography,animal model,anterior ischemic optic neuropathy
更新于2025-09-11 14:15:04
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Quantitative evaluation of osteogenesis through infrared light
摘要： Different methods are available to evaluate the degree of bone healing. A good choice involves employing optical techniques with infrared light to evaluate the progress of bone consolidation. Because infrared light is absorbed in liquids and reflected in solids, it is possible to assess bone consolidation progress using an incident light source and a coupled photo sensor. We used a 940-nm light source that is capable of reaching bone to determine the degree of bone consolidation. Five New Zealand White rabbits were used according to the NOM-062-ZOO99 standard. In each animal, a fracture was generated in the left tibia, and the fragments were fixed using an external fixator constructed with Kirschner nails and dental acrylic cement. Progress in bone consolidation was evaluated at days 7, 23, and 34 after surgery. A linear dependence was observed between the days elapsed and the reflection of the infrared light.
关键词： bone consolidation,laser diode,infrared light,animal model
更新于2025-09-11 14:15:04
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A NEW PHOTOBIOMODULATION TECHNIQUE PRODUCES A NEUROPROTECTIVE EFFECT ON AMYLOID Aβ25-35 PEPTIDE INDUCED TOXICITY IN MICE BY SYNERGISTIC MECHANISMS WHEN APPLIED BOTH ON THE HEAD AND ABDOMEN
摘要： In this work the effect of the weak combined MFs was studied in vivo in heritable animal model of AD: well characterized mice transgenic for mutant APPswe and mutant presenilin 1 (PS1dE9) that cause early onset familial Alzheimer’s disease (AD). Transgenic mice (Tg) and control C3H mice were exposed to the same MF at age of 8 months. Mice were also exposed by MF in two groups at the same time (Tg+MF and C3H+MF). A setup for generating a MF consisted of two pairs of coaxial Helmhollz coils oriented along the geomagnetic ?eld vector. A direct current was supplied to one of the pairs of coils to generate a constant component of MF with induction of 42 mcT. An alternating current signal produced by a programmable sinusoidal current generator was fed to other pair of coils to create a variable component of MF with induction of amplitude of 80 nT. The current signal was the sum of two signals with frequencies of 4.38 and 4.88 Hz. Estimation of amyloid plaque loads was performed by counting amyloid plaques, staining with thio?avine S, of the next brain areas: in the CA1 and CA3 ?elds of the hippocampus and temporal cortex of Tg mice. The effect of MFs on Ab deposits was revealed in Tg mice. That Tg+MF group showed the decreased density of plaques with small and middle sizes in the cortex and with large and middle size in the CA3, the ?eld of the hippocampus. In CA1 ?eld the tendency of the increase of small plaques was observed followed by a decrease of density of plaques with middle sizes. Thus, the data suggest that MFs can be applied for preventive purposes in a group of risk of AD.
关键词： animal model,weak combined magnetic fields,Alzheimer’s disease,amyloid-b
更新于2025-09-04 15:30:14