Low‐level light emitting diode therapy promotes long–term functional recovery after experimental stroke in mice

Abstract

We aimed to investigate the effects of low-level light emitting diode therapy (LED-T) on the long-term functional outcomes after cerebral ischemia, and the optimal timing of LED-T initiation for achieving suitable functional recovery. Focal cerebral ischemia was induced in mice via photothrombosis. These mice were assigned to a sham-operated (control), ischemic (vehicle), or LED-T group [initiation immediately (acute), 4 days (subacute) or 10 days (delayed) after ischemia, followed by once-daily treatment for 7 days]. Behavioral outcomes were assessed 21 and 28 days post-ischemia, and histopathological analysis was performed 28 days post-ischemia. The acute and subacute LED-T groups showed a significant improvement in motor function up to 28 days post-ischemia, although no brain atrophy recovery was noted. We observed proliferating cells (BrdU ) in the ischemic brain, and significant increases in BrdU /GFAP , BrdU /DCX , BrdU /NeuN , and CD31 cells in the subacute LED-T group. However, the BrdU /Iba-1 cell count was reduced in the subacute LED-T group. Furthermore, the brain-derived neurotrophic factor (BDNF) was significantly upregulated in the subacute LED-T group. We concluded that LED-T administered during the subacute stage had a positive impact on the long-term functional outcome, probably via neuron and astrocyte proliferation, blood vessel reconstruction, and increased BDNF expression. Picture: The rotarod test for motor coordination showed that acute and subacute LED-T improves long-term functional recovery after cerebral ischemia.

Light-emitting diode therapy protects against ventricular arrhythmias by neuro-immune modulation in myocardial ischemia and reperfusion rat model

“…Recently, phototherapy with light-emitting diode (LED) has been used for tissue repair with many protective effects, such as inhibiting inflammatory response and increasing collagen synthesis [9]. In an experimental ischemic stroke model, LED therapy attenuated neuroinflammatory responses and inhibited microglial activation, thus generating a smaller infarct size [10]. Therefore, we hypothesize that LED therapy might reduce VA inducibility by attenuating microglial and sympathetic activation after myocardial I/R.…”

Noninvasive light emitting diode therapy: A novel approach for postinfarction ventricular arrhythmias and neuroimmune modulation

“…PBM, including LED and low-level laser therapy, is the low power (1-500 mW) nonthermal delivery of photons that induces a beneficial biological response in cells and tissues, 40 such as stroke 16 and traumatic brain injury. 13 PBM has been increasingly used for treatment of neuroinflammation 15 and neurodegenerative diseases.…”

“…Recently, studies have shown that LED therapy might inhibit activation of microglia and increase the level of brainderived neurotrophic factor, thereby resulting in a smaller infarct size in experimental ischemic stroke. 16 Furthermore, LED therapy might attenuate inflammasomes and reduce the expression of the proinflammatory cytokines IL-1β and IL-18 in a brain ischemic stroke model. 15 In our study, we also found that LED therapy significantly attenuated inflammation, microglial activation, and AMI-induced LSG neural activation.…”

“…14 Previous studies have found LED therapy attenuates neuroinflammatory responses 15 and inhibits microglial activation in experimental ischemic stroke. 16 Therefore, we hypothesize that LED therapy might reduce microglial activation, which breaks the vicious cycle between the increase of SNA and microglial activation, ultimately alleviating AMI-induced VAs. In the present study, we explored the effect of LED exposure to the skull surface of hypothalamic PVN on AMI-induced VAs and neuroimmune activation.…”

Light Emitting Diode Therapy Protects against Myocardial Ischemia/Reperfusion Injury through Mitigating Neuroinflammation

“…Recently, previous studies have shown that both M2 microglia and BDNF exert antineuroinflammatory effects [ 11 – 14 ]. Furthermore, LED therapy has been widely used in neurological and brain injury treatment [ 15 , 16 ]. Moreover, studies have shown that LED therapy might increase M2 microglia and BDNF in the brain, thereby decreasing the ischemic stroke injury [ 17 , 18 ].…”